Author name code: hawley ADS astronomy entries on 2022-09-14 author:"Hawley, Suzanne L." ------------------------------------------------------------------------ Title: Llamaradas Estelares: Modeling the Morphology of White-light Flares Authors: Mendoza, Guadalupe Tovar; Davenport, James R. A.; Agol, Eric; Jackman, James A. G.; Hawley, Suzanne L. Bibcode: 2022AJ....164...17M Altcode: Stellar variability is a limiting factor for planet detection and characterization, particularly around active M-type stars. Here we revisit one of the most active stars from the Kepler mission, the M4 star GJ 1243, and use a sample of 414 flare events from 11 months of 1-minute cadence light curves to study the empirical morphology of white-light stellar flares. We use a Gaussian process detrending technique to account for the underlying starspots. We present an improved analytic, continuous flare template that is generated by stacking the flares onto a scaled time and amplitude and uses a Markov Chain Monte Carlo analysis to fit the model. Our model is defined using classical flare events but can also be used to model complex, multipeaked flare events. We demonstrate the utility of our model using TESS data at the 10-minute, 2-minute, and 20 s cadence modes. Our new flare model code is made publicly available on GitHub. 5 5 https://github.com/lupitatovar/Llamaradas-Estelares Title: Blue asymmetries in Balmer lines and possible mass ejections during mid M dwarf flares Authors: Notsu, Yuta; Shibata, Kazunari; Enoto, Teruaki; Hamaguchi, Kenji; Honda, Satoshi; Maehara, Hiroyuki; Nogami, Daisaku; Ikuta, Kai; Kowalski, Adam; Hawley, Suzanne; Davenport, James; Tristan, Isaiah; Namekata, Kosuke Bibcode: 2022cosp...44.1382N Altcode: Flares are releases of magnetic energy in the solar/stellar atmosphere, and they have strong emissions from radio to X-rays. During some M dwarf flares, chromospheric line profiles show blue asymmetries (Honda et al. 2018), although red asymmetries are more commonly observed in solar flares. Similar enhancements of the blue wings of Balmer lines may provide clues for investigating the early phases of stellar coronal mass ejections (CMEs) during flares (cf. Vida et al. 2016&2019), but this is still controversial. Thus, we need simultaneous spectroscopic and photometric observations of flares with high time resolution to understand the relationship between mass ejections and flaring events. We have conducted simultaneous spectroscopic and photometric observations of mid M dwarf flare stars (YZCMi, EVLac, ADLeo) using APO 3.5m/ARCES, SMARTS 1.5m/CHIRON, Nayuta 2m/MALLS (high-dispersion spectroscopy), TESS (space high-precision single-color photometry), ground-based 0.4-1m telescopes (ground-based photometry), and NICER (X-ray spectroscopy). During 34 nights of observations, we detected more than 46 flares in Balmer lines (e.g. H$\alpha$). Among them, at least 8 flare event showed clear blue asymmetries with velocities 100-200 km s$ ^{-1}$(Maehara et al. 2021 PASJ, Notsu et al. in prep). We found various correspondences in the durations of blue asymmetries and intensities of white light emissions. In most cases, while the blue asymmetries were not significant in the higher-order Balmer lines and other chromospheric lines such as the Ca II K/8542A line. As for one event, we succeeded in the simultaneous observation of the blue asymmetry and X-ray flare for the first time. These results might be a clue to investigate the formation processes of the blue-shifted components, and discuss how blue asymmteries are helpful for dicussing CME properties. By assuming that the blue asymmetries were caused by prominence eruptions, we estimate the mass and kinetic energy of the upward-moving material to be 10$ ^{15}$ — 10$ ^{18}$ g and 10$ ^{29}$ —10$ ^{32}$ erg, respectively. The estimated masses are comparable to expectations from the empirical relation between the flare X-ray energy and mass of upward-moving material for stellar flares and solar CMEs. In contrast, the estimated kinetic energies for these non-white-light flares are roughly 2-3 orders of magnitude smaller than that expected from the relation between flare X-ray energy and kinetic energy for solar CMEs. This could be understood by the difference in the velocity between CMEs and prominence eruptions. Title: Modeling Stellar Surface Features on a Subgiant Star with an M-dwarf Companion Authors: Schutte, Maria C.; Hebb, Leslie; Lowry, Simon; Wisniewski, John; Hawley, Suzanne L.; Mahadevan, Suvrath; Morris, Brett M.; Robertson, Paul; Rohn, Graeme; Stefansson, Gudmundur Bibcode: 2022AJ....164...14S Altcode: 2022arXiv220508620S Understanding magnetic activity on the surface of stars other than the Sun is important for exoplanet analyses to properly characterize an exoplanet's atmosphere and to further characterize stellar activity on a wide range of stars. Modeling stellar surface features of a variety of spectral types and rotation rates is key to understanding the magnetic activity of these stars. Using data from Kepler, we use the starspot modeling program STarSPot (STSP) to measure the position and size of spots for KOI-340, which is an eclipsing binary consisting of a subgiant star (T eff = 5593 ± 27 K, R ⋆ = 1.98 ± 0.05 R ⊙) with an M-dwarf companion (M ⋆ = 0.214 ± 0.006 M ⊙). STSP uses a novel technique to measure the spot positions and radii by using the transiting secondary to study and model individual active regions on the stellar surface using high-precision photometry. We find that the average size of spot features on KOI-340's primary is ~10% the radius of the star, i.e., two times larger than the mean size of solar-maximum sunspots. The spots on KOI-340 are present at every longitude and show possible signs of differential rotation. The minimum fractional spotted area of KOI-340's primary is ${2}_{-2}^{+12}{\rm{ \% }}$ , while the spotted area of the Sun is at most 0.2%. One transit of KOI-340 shows a signal in the transit consistent with a plage; this plage occurs right before a dark spot, indicating that the plage and spot might be colocated on the surface of the star. Title: Llamaradas Estelares: Modeling the Morphology of White-Light Flares Authors: Tovar Mendoza, Guadalupe; Davenport, James R. A.; Agol, Eric; Jackman, James A. G.; Hawley, Suzanne L. Bibcode: 2022arXiv220505706T Altcode: Stellar variability is a limiting factor for planet detection and characterization, particularly around active M-type stars. Here we revisit one of the most active stars from the Kepler mission, the M4 star GJ 1243, and use a sample of 414 flare events from 11 months of 1-minute cadence light curves to study the empirical morphology of white-light stellar flares. We use a Gaussian process detrending technique to account for the underlying starspots. We present an improved analytic, continuous flare template that is generated by stacking the flares onto a scaled time and amplitude and uses a Markov Chain Monte Carlo analysis to fit the model. Our model is defined using classical flare events, but can also be used to model complex, multi-peaked flare events. We demonstrate the utility of our model using TESS data at the 10-minute, 2-minute and 20-second cadence modes. Our new flare model code is made publicly available on GitHub. Title: Recent observations of stellar flares on G-, K-, and M-dwarf stars and possible mass ejections Authors: Notsu, Yuta; Kowalski, Adam; Maehara, Hiroyuki; Namekata, Kosuke; Tristan, Isaiah; Okamoto, Soshi; Ikuta, Kai; Hawley, Suzanne; Davenport, James; Enoto, Teruaki; Hamaguchi, Kenji; Nogami, Daisaku; Shibata, Kazunari Bibcode: 2021AGUFM.U43B..01N Altcode: Flares are frequent energetic explosions in the stellar atmosphere, and are thought to occur by impulsive releases of magnetic energy stored around starspots. Large flares (so called superflares) generate strong high energy emissions and coronal mass ejections (CMEs), which can greatly affect the planetary environment and habitability. Recent Kepler/TESS photometric data have revealed the statistical properties of superflares on G, K, M-type stars. Superflare stars are well characterized by the existence of large starspots on the surface, and their magnetic fluxes can explain well superflare energies. Flare frequency/energy depends on stellar rotation period and stellar temperature. Young rapidly-rotating stars and cooler stars tend to have frequent flares, which can be more hazardous for the habitable planets. However, we still do not know the emission mechanisms of superflares, and how large CMEs are associated with superflares on these active stars. Then recently, these active superflare stars have been investigated in more detail thorugh recent multi-wavelength surveys. For example, Hydrogen chromospheric lines during flares show blue-shifted profiles, which can give us some hints on dynamics or mass ejections during superflares. In the early part of this invited overview talk, I briefly overview the recent statistical results of superflares from Kepler/TESS data. Then in the latter part, I also briefly discuss the results of recent multi-wavelength campaign observations of superflares, and discuss possible detections of mass ejections (stellar CMEs). Title: VizieR Online Data Catalog: IRD and HPF spectra of TRAPPIST-1b,e and f (Krishnamurthy+, 2021) Authors: Krishnamurthy, V.; Hirano, T.; Stefansson, G.; Ninan, J. P.; Mahadevan, S.; Gaidos, E.; Kopparapu, R.; Sato, B.; Hori, Y.; Bender, C. F.; Canas, C. I.; Diddams, S. A.; Halverson, S.; Harakawa, H.; Hawley, S.; Hearty, F.; Hebb, L.; Hodapp, K.; Jacobson, S.; Kanodia, S.; Konishi, M.; Kotani, T.; Kowalski, A.; Kudo, T.; Kurokawa, T.; Kuzuhara, M.; Lin, A.; Maney, M.; Metcalf, A. J.; Morris, B.; Nishikawa, J.; Omiya, M.; Robertson, P.; Roy, A.; Schwab, C.; Serizawa, T.; Tamura, M.; Ueda, A.; Vievard, S.; Wisniewski, J. Bibcode: 2021yCat..51620082K Altcode: We observed a photometric transit of TRAPPIST-1b on the night of UT 2020 September 5 using the Astrophysical Research Consortium Telescope Imaging Camera (ARCTIC) on the 3.5m Astrophysical Research Consortium Telescope at Apache Point Observatory. We adopted the SDSS filter using an exposure time of 18s in the 4x4 binning fast-readout mode.

We observed the transit of TRAPPIST-1b on the night of UT 2020 September 17 using Infrared Doppler (IRD), which has a spectral resolution of ~70000 in the operating wavelength range of 0.95-1.75μm, mounted on the 8.2m Subaru Telescope on Maunakea, Hawaii.

Habitable Planet Finder (HPF) is a fiber-fed high-resolution (R=55000) spectrograph on the 10m Hobby-Eberly Telescope (HET) at McDonald Observatory in Texas. Using HPF, we obtained three transits on the nights of UT 2018 October 2, 2019 July 31, and 2020 September 5.

(3 data files). Title: A Search for Planetary Metastable Helium Absorption in the V1298 Tau System Authors: Vissapragada, Shreyas; Stefánsson, Gudmundur; Greklek-McKeon, Michael; Oklopčić, Antonija; Knutson, Heather A.; Ninan, Joe P.; Mahadevan, Suvrath; Cañas, Caleb I.; Chachan, Yayaati; Cochran, William D.; Collins, Karen A.; Dai, Fei; David, Trevor J.; Halverson, Samuel; Hawley, Suzanne L.; Hebb, Leslie; Kanodia, Shubham; Kowalski, Adam F.; Livingston, John H.; Maney, Marissa; Metcalf, Andrew J.; Morley, Caroline; Ramsey, Lawrence W.; Robertson, Paul; Roy, Arpita; Spake, Jessica; Schwab, Christian; Terrien, Ryan C.; Tinyanont, Samaporn; Vasisht, Gautam; Wisniewski, John Bibcode: 2021AJ....162..222V Altcode: 2021arXiv210805358V Early in their lives, planets endure extreme amounts of ionizing radiation from their host stars. For planets with primordial hydrogen and helium-rich envelopes, this can lead to substantial mass loss. Direct observations of atmospheric escape in young planetary systems can help elucidate this critical stage of planetary evolution. In this work, we search for metastable helium absorption-a tracer of tenuous gas in escaping atmospheres-during transits of three planets orbiting the young solar analog V1298 Tau. We characterize the stellar helium line using HET/HPF, and find that it evolves substantially on timescales of days to months. The line is stable on hour-long timescales except for one set of spectra taken during the decay phase of a stellar flare, where absoprtion increased with time. Utilizing a beam-shaping diffuser and a narrowband filter centered on the helium feature, we observe four transits with Palomar/WIRC: two partial transits of planet d (P = 12.4 days), one partial transit of planet b (P = 24.1 days), and one full transit of planet c (P = 8.2 days). We do not detect the transit of planet c, and we find no evidence of excess absorption for planet b, with ΔR b/R ⋆ < 0.019 in our bandpass. We find a tentative absorption signal for planet d with ΔR d/R ⋆ = 0.0205 ± 0.054, but the best-fit model requires a substantial (-100 ± 14 minutes) transit-timing offset on a two-month timescale. Nevertheless, our data suggest that V1298 Tau d may have a high present-day mass-loss rate, making it a priority target for follow-up observations. Title: TOI-532b: The Habitable-zone Planet Finder confirms a Large Super Neptune in the Neptune Desert orbiting a metal-rich M-dwarf host Authors: Kanodia, Shubham; Stefansson, Gudmundur; Cañas, Caleb I.; Maney, Marissa; Lin, Andrea S. J.; Ninan, Joe P.; Jones, Sinclaire; Monson, Andrew; Parker, Brock A.; Kobulnicky, Henry A.; Rothenberg, Jason; Beard, Corey; Lubin, Jack; Robertson, Paul; Gupta, Arvind F.; Mahadevan, Suvrath; Cochran, William D.; Bender, Chad F.; Diddams, Scott A.; Fredrick, Connor; Halverson, Samuel; Hawley, Suzanne; Hearty, Fred; Hebb, Leslie; Kopparapu, Ravi; Metcalf, Andrew J.; Ramsey, Lawrence W.; Roy, Arpita; Schwab, Christian; Schutte, Maria; Terrien, Ryan C.; Wisniewski, John; Wright, Jason T. Bibcode: 2021AJ....162..135K Altcode: 2021arXiv210713670K We confirm the planetary nature of TOI-532b, using a combination of precise near-infrared radial velocities with the Habitable-zone Planet Finder, Transiting Exoplanet Survey Satellite (TESS) light curves, ground-based photometric follow up, and high-contrast imaging. TOI-532 is a faint (J ~ 11.5) metal-rich M dwarf with Teff = 3957 ± 69 K and [Fe/H] = 0.38 ± 0.04; it hosts a transiting gaseous planet with a period of ~2.3 days. Joint fitting of the radial velocities with the TESS and ground-based transits reveal a planet with radius of 5.82 ± 0.19 R⊕, and a mass of ${61.5}_{-9.3}^{+9.7}$ M⊕. TOI-532b is the largest and most massive super Neptune detected around an M dwarf with both mass and radius measurements, and it bridges the gap between the Neptune-sized planets and the heavier Jovian planets known to orbit M dwarfs. It also follows the previously noted trend between gas giants and host-star metallicity for M-dwarf planets. In addition, it is situated at the edge of the Neptune desert in the Radius-Insolation plane, helping place constraints on the mechanisms responsible for sculpting this region of planetary parameter space. Title: Nondetection of Helium in the Upper Atmospheres of TRAPPIST-1b, e, and f Authors: Krishnamurthy, Vigneshwaran; Hirano, Teruyuki; Stefánsson, Gumundur; Ninan, Joe P.; Mahadevan, Suvrath; Gaidos, Eric; Kopparapu, Ravi; Sato, Bunei; Hori, Yasunori; Bender, Chad F.; Cañas, Caleb I.; Diddams, Scott A.; Halverson, Samuel; Harakawa, Hiroki; Hawley, Suzanne; Hearty, Fred; Hebb, Leslie; Hodapp, Klaus; Jacobson, Shane; Kanodia, Shubham; Konishi, Mihoko; Kotani, Takayuki; Kowalski, Adam; Kudo, Tomoyuki; Kurokawa, Takashi; Kuzuhara, Masayuki; Lin, Andrea; Maney, Marissa; Metcalf, Andrew J.; Morris, Brett; Nishikawa, Jun; Omiya, Masashi; Robertson, Paul; Roy, Arpita; Schwab, Christian; Serizawa, Takuma; Tamura, Motohide; Ueda, Akitoshi; Vievard, Sébastien; Wisniewski, John Bibcode: 2021AJ....162...82K Altcode: 2021arXiv210611444K We obtained high-resolution spectra of the ultracool M-dwarf TRAPPIST-1 during the transit of its planet "b" using two high-dispersion near-infrared spectrographs, the Infrared Doppler (IRD) instrument on the Subaru 8.2m telescope, and the Habitable Zone Planet Finder (HPF) instrument on the 10 m Hobby-Eberly Telescope. These spectroscopic observations are complemented by a photometric transit observation for planet "b" using the APO/ARCTIC, which assisted us in capturing the correct transit times for our transit spectroscopy. Using the data obtained by the new IRD and HPF observations, as well as the prior transit observations of planets "b," "e" and "f" from IRD, we attempt to constrain the atmospheric escape of the planet using the He I triplet 10830 Å absorption line. We do not detect evidence for any primordial extended H-He atmospheres in all three planets. To limit any planet-related absorption, we place an upper limit on the equivalent widths of <7.754 mÅ for planet "b," <10.458 mÅ for planet "e," <4.143 mÅ for planet "f" at 95% confidence from the IRD data, and <3.467 mÅ for planet "b" at 95% confidence from HPF data. Using these limits along with a solar-like composition isothermal Parker wind model, we attempt to constrain the mass-loss rates for the three planets. For TRAPPIST-1b, our models exclude the highest possible energy-limited rate for a wind temperature <5000 K. This nondetection of extended atmospheres with low mean-molecular weights in all three planets aids in further constraining their atmospheric composition by steering the focus toward the search of high-molecular-weight species in their atmospheres. *Based on data collected at Subaru Telescope, operated by the National Astronomical Observatory of Japan, Hobby-Eberly Telescope operated by The University of Texas McDonald Observatory, and ARC 3.5m Telescope at Apache Point Observatory. Title: Blue asymmetries in Balmer lines during mid M dwarf flares Authors: Notsu, Yuta; Kowalski, Adam F.; Maehara, Hiroyuki; Namekata, Kosuke; Honda, Satoshi; Enoto, Teruaki; Hamaguchi, Kenji; Tristan, Isaiah; Hawley, Suzanne L.; Davenport, James R. A.; Okamoto, Soshi; Ikuta, Kai; Nogami, Daisaku; Shibata, Kazunari Bibcode: 2021tsc2.confE.118N Altcode: Flares are releases of magnetic energy in the stellar atmosphere, and they have strong emissions from radio to X-rays. During some M dwarf flares, chromospheric line profiles show blue asymmetries, although red asymmetries are more commonly observed in solar flares. Similar enhancements of the blue wings of Balmer lines may provide clues for investigating the early phases of stellar coronal mass ejections (CMEs), but this is still controversial. Thus, we need more observations to understand the relationship between mass ejections and flares. We have conducted simultaneous spectroscopic and photometric observations of mid M dwarf flare stars using APO 3.5m/ARCES, SMARTS1.5m/CHIRON, TESS, and etc. During 34 night observations, we detected 48 flares in Balmer lines (e.g. Hα). At least 7 flares show clear blue asymmetries. Blue asymmetry durations are different among the 7 events (20min ~ 2hr). These results suggest upward flows of chromospheric plasma during flare events. By assuming that the blue asymmetries were caused by prominence eruptions, we estimated the mass and kinetic energy. The estimated masses are comparable to expectations from the empirical relation between the flare X-ray energy and mass of solar CMEs. Title: Modeling the Morphology of White-Light Flares Authors: Tovar Mendoza, Guadalupe; Davenport, James R. A.; Hawley, Suzanne L. Bibcode: 2021tsc2.confE.149T Altcode: Stellar variability is a limiting factor for planet detection and characterization, particularly around active stars. By understanding the light curve profile of flares on active M-dwarfs we can help improve exoplanet detection and characterization. Here we revisit one of the most active stars from the Kepler mission, the M4 dwarf GJ 1243, and use a sample of 303 stellar flares from 11 months of 1-minute cadence light curves to study the empirical morphology of stellar flares. We use a Gaussian process detrending technique to account for the underlying starspots. We present an improved analytic, continuous flare template that is generated by stacking the flares in a scaled time and amplitude and using Markov Chain Monte Carlo to fit the model. Our model is defined using classical flare events, but can also be used to model complex, multi-peaked flare events. We test our model using TESS data at both the 2-minute and 20-second cadence modes, showing the general utility of our empirical flare template. Title: The Mega-MUSCLES Spectral Energy Distribution of TRAPPIST-1 Authors: Wilson, David J.; Froning, Cynthia S.; Duvvuri, Girish M.; France, Kevin; Youngblood, Allison; Schneider, P. Christian; Berta-Thompson, Zachory; Brown, Alexander; Buccino, Andrea P.; Hawley, Suzanne; Irwin, Jonathan; Kaltenegger, Lisa; Kowalski, Adam; Linsky, Jeffrey; Parke Loyd, R. O.; Miguel, Yamila; Pineda, J. Sebastian; Redfield, Seth; Roberge, Aki; Rugheimer, Sarah; Tian, Feng; Vieytes, Mariela Bibcode: 2021ApJ...911...18W Altcode: 2021arXiv210211415W We present a 5 Å-100 μm spectral energy distribution (SED) of the ultracool dwarf star TRAPPIST-1, obtained as part of the Mega-MUSCLES Treasury Survey. The SED combines ultraviolet and blue-optical spectroscopy obtained with the Hubble Space Telescope, X-ray spectroscopy obtained with XMM-Newton, and models of the stellar photosphere, chromosphere, transition region, and corona. A new differential emission measure model of the unobserved extreme-ultraviolet spectrum is provided, improving on the Lyα-EUV relations often used to estimate the 100-911 Å flux from low-mass stars. We describe the observations and models used, as well as the recipe for combining them into an SED. We also provide a semiempirical, noise-free model of the stellar ultraviolet spectrum based on our observations for use in atmospheric modeling of the TRAPPIST-1 planets. Title: From Kepler to TESS: 10 Years of Flare Activity from Space Authors: Davenport, James; Tovar Mendoza, Guadalupe; Hawley, Suzanne Bibcode: 2021csss.confE..27D Altcode: We have carried out the first flare and starspot analysis of GJ 1243 from over 50 days of data from TESS Sectors 14 and 15. Using 133 flare events detected in the 2 minute cadence TESS data, we compare the cumulative flare frequency distributions, and find the flare activity for GJ 1243 is unchanged between the Kepler and TESS epochs. Two distinct starspot groups are found in the TESS data, with the primary spot having the same rotational period and phase as in Kepler. As expected for this highly active M4, the constant spot and flare activity reveal no sign of solar-like activity cycles over 10 yr. However, we highlight the unique ability for Kepler and TESS to use flare rates to detect activity cycles for many years to come. New 20-second cadence data from TESS will also allow us to test the widely used empirical flare profile created for GJ 1243 using Kepler 1-minute data. Title: Blue asymmetries in Balmer lines during mid M dwarf flares Authors: Notsu, Yuta; Kowalski, Adam F.; Maehara, Hiroyuki; Namekata, Kosuke; Honda, Satoshi; Enoto, Teruaki; Hamaguchi, Kenji; Tristan, Isaiah; Hawley, Suzanne L.; Davenport, James R. A.; Okamoto, Soshi; Ikuta, Kai; Nogami, Daisaku; Shibata, Kazunari Bibcode: 2021csss.confE.103N Altcode: Flares are releases of magnetic energy in the solar/stellar atmosphere, and they have strong emissions from radio to X-rays. During some M dwarf flares, chromospheric line profiles show blue asymmetries (Eason et al. 1992; Honda et al. 2018), although red asymmetries are more commonly observed in solar flares. Similar enhancements of the blue wings of Balmer lines may provide clues for investigating the early phases of stellar coronal mass ejections (CMEs) during flares (cf. Vida et al. 2016&2019), but this is still controversial. Thus, we need more flare spectroscopic observations with high time resolution to understand the relationship between mass ejections and flaring events. The latter is helpful for estimating the impact on planets from flares.We have conducted several simultaneous spectroscopic and photometric observations of mid M dwarf flare stars using APO 3.5m/ARCES, SMARTS 1.5m/CHIRON, TESS, and ground- based 0.4-1m photometric telescopes. During 34 nights of observations, we detected 48 flares in Balmer lines (e.g. H-alpha). Among them, at least 7 flare events show clear blue asymmetries. Blue asymmetry durations are different among the 7 events (20min ~ 2hr).These results suggest upward flows of chromospheric plasma during flare events. By assuming that the blue asymmetries were caused by prominence eruptions, we estimate the mass and kinetic energy of the upward-moving material to be 1015 - 1018 g and 1029 - 1032 erg, respectively. The estimated masses are comparable to expectations from the empirical relation between the flare X-ray energy and mass of upward-moving material for stellar flares and solar CMEs. In contrast, the estimated kinetic energies for these non-white-light flares are roughly 2-3 orders of magnitude smaller than that expected from the relation between flare X-ray energy and kinetic energy for solar CMEs. This could be understood by the difference in the velocity between CMEs and prominence eruptions. Title: Blue asymmetries in Balmer lines during mid M dwarf flares Authors: Notsu, Y.; Kowalski, A.; Maehara, H.; Namekata, K.; Honda, S.; Enoto, T.; Hamaguchi, K.; Tristan, I.; Hawley, S.; Davenport, J.; Okamoto, S.; Ikuta, K.; Nogami, D.; Shibata, K. Bibcode: 2021AAS...23751501N Altcode: Flares are releases of magnetic energy in the solar/stellar atmosphere, and they have strong emissions from radio to X-rays. During some M dwarf flares, chromospheric line profiles show blue asymmetries (Honda et al. 2018), although red asymmetries are more commonly observed in solar flares. Similar enhancements of the blue wings of Balmer lines may provide clues for investigating the early phases of stellar coronal mass ejections (CMEs) during flares (cf. Vida et al. 2016&2019), but this is still controversial. Thus, we need more flare spectroscopic observations with high time resolution to understand the relationship between mass ejections and flaring events. The latter is helpful for estimating the impact on planets from flares. We have conducted several simultaneous spectroscopic and photometric observations of mid M dwarf flare stars using APO 3.5m/ARCES, SMARTS 1.5m/CHIRON, Nayuta 2m/MALLS (high-dispersion spectroscopy), TESS (space high-precision single-color photometry), and ground-based 0.4-1m telescopes (ground-based photometry). During ~20 nights of observations, we detected more than 30 flares in Balmer lines (e.g. Hα). Among them, at least 6 flare events (including one already reported in Maehara et al. 2020) show clear blue asymmetries, but none show brightening in the continuum. Blue asymmetry durations are different among the 6 events (20min ~ 2hr). These results suggest upward flows of chromospheric plasma during "non-white light" flare events. By assuming that the blue asymmetries were caused by prominence eruptions, we estimate the mass and kinetic energy of the upward-moving material to be 1015-1018 g and 1029-1032 erg, respectively. The estimated masses are comparable to expectations from the empirical relation between the flare X-ray energy and mass of upward-moving material for stellar flares and solar CMEs. In contrast, the estimated kinetic energies for these non-white-light flares are roughly 2 orders of magnitude smaller than that expected from the relation between flare X-ray energy and kinetic energy for solar CMEs. This could be understood by the difference in the velocity between CMEs and prominence eruptions. Title: Superflares investigated with Kepler&TESS photometric data and recent multi-wavelength campaign observations Authors: Notsu, Yuta; Shibata, Kazunari; Enoto, Teruaki; Hamaguchi, Kenji; Honda, Satoshi; Maehara, Hiroyuki; Nogami, Daisaku; Namekata, Kosuke; Ikuta, Kai; Kowalski, Adam; Hawley, Suzanne; Davenport, James; Okamoto, Soshi; Notsu, Shota Bibcode: 2021cosp...43E1750N Altcode: Solar flares are frequent energetic explosions in the solar atmosphere, and are thought to occur by impulsive releases of magnetic energy stored around sunspots. Large solar flares sometimes can have large impacts on our Earth and society (e.g., magnetic storms). Stars other than the Sun also show flares. Many young stars, active M-dwarfs known as flare stars, and close binary stars have ``superflares'', which are flares that have a total energy 10--10$^{6}$ times larger than that of the largest solar flares on the Sun ($\sim$10$^{32}$ erg). These stars generally rotate very fast (Period $\sim$ 2--3 days). In contrast, the Sun slowly rotates (Period $\sim$25 days). Then it had been thought that superflares cannot occur on slowly-rotating G-type main-sequence stars like the Sun. Recently, more than 1000 superflares on solar-type stars (G-type main sequence stars) have been found using the photometric data of Kepler spece telescope (and also TESS satellite). Using these large number of data, it is now possible to do statistical studies of superflares on solar-type stars. First, superflare stars are well characterized by the existence of large starspots on the surface, and their magnetic fluxes can explain well superflare energies. Then, maximum superflare energy continuously decreases as the rotation period increases. Superflares with their energy $\le \sim$ 5$\times$10$^{34}$ erg (a few hundred times larger than the largest solar flares) would occur on old slowly-rotating Sun-like stars (Rotation Period $\sim$25 days) once every 2000-3000 years, while young rapidly-rotating stars with Rotation Period $\sim$ a few days have superflares up to 10$^{36}$ erg. These results presented in this work support that even slowly-rotating stars similar to the Sun can have superflares, considering long-term activity level changes. In addition to these photometric observation results of solar-type superflare stars, cool M-dwarf superflare stars have been investigated in more detail by recent multi-wavelength surveys. For example, Hydrogen chromospheric lines during flares show a lot of blue-shifted profiles, which can give us some hints on dynamics or mass ejections during superflares. In the main part of this review talk, I review the recent statistical results of superflares from Kepler\&TESS data. Then in the latter part, I also briefly discuss the results of recent multi-wavelength campaign observations of M-dwarf superflares, and finally show the future prospects of superflare studies, which are closely related with solar physics and studies of effects on planets. Title: 10 Years of Stellar Activity for GJ 1243 Authors: Davenport, James. R. A.; Mendoza, Guadalupe Tovar; Hawley, Suzanne L. Bibcode: 2020AJ....160...36D Altcode: 2020arXiv200510281D The flaring M4 dwarf GJ 1243 has become a benchmark for studying stellar flare and starspot activity thanks to the exceptional photometric monitoring archive from the Kepler mission. New light curves from the Transiting Exoplanet Survey Satellite (TESS) mission for this star allow precise stellar activity characterization over more than a decade timescale. We have carried out the first flare and starspot analysis of GJ 1243 from over 50 days of data from TESS Sectors 14 and 15. Using 133 flare events detected in the 2 minute cadence TESS data, we compare the cumulative flare frequency distributions, and find the flare activity for GJ 1243 is unchanged between the Kepler and TESS epochs. Two distinct starspot groups are found in the TESS data, with the primary spot having the same rotational period and phase as seen in Kepler. The phase of the secondary spot feature is consistent with the predicted location of the secondary starspot and measurement of weak differential rotation, suggesting this secondary spot may be long-lived and stable in both latitude and longitude. As expected for this highly active star, the constant spot and flare activity reveal no sign of solar-like activity cycles over 10 yr. However, we highlight the unique ability for Kepler and TESS to use flare rates to detect activity cycles. Title: The stellar variability noise floor for transiting exoplanet photometry with PLATO Authors: Morris, Brett M.; Bobra, Monica G.; Agol, Eric; Lee, Yu Jin; Hawley, Suzanne L. Bibcode: 2020MNRAS.493.5489M Altcode: 2020arXiv200208072M; 2020MNRAS.tmp..581M One of the main science motivations for the ESA PLAnetary Transit and Oscillations (PLATO) mission is to measure exoplanet transit radii with 3 per cent precision. In addition to flares and starspots, stellar oscillations and granulation will enforce fundamental noise floors for transiting exoplanet radius measurements. We simulate light curves of Earth-sized exoplanets transiting continuum intensity images of the Sun taken by the Helioseismic and Magnetic Imager (HMI) instrument aboard the Solar Dynamics Observatory (SDO) to investigate the uncertainties introduced on the exoplanet radius measurements by stellar granulation and oscillations. After modelling the solar variability with a Gaussian process, we find that the amplitude of solar oscillations and granulation is of order 100 ppm - similar to the depth of an Earth transit - and introduces a fractional uncertainty on the depth of transit of 0.73 per cent assuming four transits are observed over the mission duration. However, when we translate the depth measurement into a radius measurement of the planet, we find a much larger radius uncertainty of 3.6 per cent. This is due to a degeneracy between the transit radius ratio, the limb darkening, and the impact parameter caused by the inability to constrain the transit impact parameter in the presence of stellar variability. We find that surface brightness inhomogeneity due to photospheric granulation contributes a lower limit of only 2 ppm to the photometry in-transit. The radius uncertainty due to granulation and oscillations, combined with the degeneracy with the transit impact parameter, accounts for a significant fraction of the error budget of the PLATO mission, before detector or observational noise is introduced to the light curve. If it is possible to constrain the impact parameter or to obtain follow-up observations at longer wavelengths where limb darkening is less significant, this may enable higher precision radius measurements. Title: Temporal Evolution of Spatially Resolved Individual Star Spots on a Planet-hosting Solar-type Star: Kepler-17 Authors: Namekata, Kosuke; Davenport, James R. A.; Morris, Brett M.; Hawley, Suzanne L.; Maehara, Hiroyuki; Notsu, Yuta; Toriumi, Shin; Ikuta, Kai; Notsu, Shota; Honda, Satoshi; Nogami, Daisaku; Shibata, Kazunari Bibcode: 2020ApJ...891..103N Altcode: 2020arXiv200201086N Star spot evolution is visible evidence of the emergence/decay of the magnetic field on a stellar surface, and it is therefore important for the understanding of the underlying stellar dynamo and consequential stellar flares. In this paper, we report the temporal evolution of individual star spot areas on the hot-Jupiter-hosting, active solar-type star Kepler-17, whose transits occur every 1.5 days. The spot longitude and area evolution are estimated (1) from the stellar rotational modulations of Kepler data and (2) from the brightness enhancements during the exoplanet transits caused by existence of large star spots. As a result of the comparison, the number of spots, spot locations, and the temporal evolution derived from the rotational modulations are largely different from those of in-transit spots. We confirm that, although only two light-curve minima appear per rotation, there are clearly many spots present on the star. We find that the observed differential intensity changes are sometimes consistent with the spot pattern detected by transits, but at other times they do not match with each other. Although the temporal evolution derived from the rotational modulation differs from those of in-transit spots to a certain degree, the emergence/decay rates of in-transit spots are within an order of magnitude of those derived for sunspots as well as our previous research based only on rotational modulations. This supports the hypothesis that the emergence/decay of sunspots and extremely large star spots on solar-type stars occur through the same underlying processes. Title: Lifetimes and emergence/decay rates of star spots on solar-type stars estimated by Kepler data in comparison with those of sunspots Authors: Namekata, K.; Shibata, K.; Maehara, H.; Notsu, Y.; Nogami, D.; Toriumi, S.; Davenport, J.; Hawley, S.; Morris, B. Bibcode: 2020AAS...23514805N Altcode: Active solar-type stars show large quasi-periodic brightness variations caused by stellar rotations with large star spots, and the amplitude changes as the spots emerge and decay. Temporal evolution of star spots has been hardly measured because of its difficulty in measurement, especially on solar-type stars. The Kepler's long-term data are suitable for investigations on the emergence and decay processes of star spots, which are important to understand underlying stellar dynamo. In this talk, we report the measurements of temporal evolution of individual star-spot area on solar-type stars by using Kepler data. We estimated it (i) by tracing local minima of the Kepler light curves (Namekata et al. 2019) and (ii) by modeling the small brightness variation during exoplanet transit (c.f. Morris et al. 2017, Namekata et al. submitted to ApJ). We successfully obtained temporal evolution of individual star spots showing clear emergence and decay, and derived the statistical values of the lifetimes and emergence/decay rates of star spots. As a result, we found that lifetimes (T) of star spots are ranging from 10 to 350 days when spot areas (A) are 0.1-2.3% of a solar hemisphere (SH). The lifetimes of star spots are much shorter than those extrapolated from an empirical relation of sunspots, while being consistent with other researches on star spot lifetimes. The emerging and decay rates of star spots are typically 5×1020 Mx/h (8 MSH/h) with the area of 0.1-2.3% of SH and are mostly consistent with those expected from sunspots observations (Petrovay et al. 1997, Norton et al. 2017). This strongly supports a possibility that the emergence/decay mechanism of extremely large star spots (0.1-2.3% of SH) is same as that of smaller sunspots (< 0.5% of SH), which can constrain the stellar dynamo theory. Title: Blue asymmetries of Balmer lines during M-dwarf flares investigated with multi-wavelength observations Authors: Notsu, Y.; Kowalski, A.; Maehara, H.; Namekata, K.; Hawley, S.; Davenport, J.; Enoto, T.; Hamaguchi, K.; Honda, S.; Notsu, S.; Ikuta, K.; Nogami, D.; Shibata, K. Bibcode: 2020AAS...23528805N Altcode: Flares are magnetic energy release in the solar/stellar atmosphere, and they have strong emissions from radio to X-rays. During some M-dwarf superflares, chromospheric line profiles show blue asymmetries (Honda et al. 2018), though red asymmetries have been seen during many ordinary solar flares. it is also thought that similar enhancements of the blue wing of Balmer lines can provide clues for investigating mass ejections from flares (stellar CMEs) (cf. Vida et al. 2016&2019), but this is still very controversial. Thus, we need more flare spectroscopic observations with high time resolution for understanding how superflares occur and how large mass ejections occur during superflares occur. The latter is helpful for estimating the impacts on planets from superflares. We have conducted several simultaneous spectroscopic and photometric observations of M-dwarf flare stars. In 2019 January, we observed a M-dwarf flare star YZCMi using APO3.5m/ARCES (high-dispersion spectroscopy), APO/ARCSAT0.5m (multi-color photometry), TESS (space high-precision single-color photometry), and NICER (soft X-ray telescope on ISS). During the observation, we detected large enhancements of chromospheric lines lasting for longer than 3 hours (e.g., H- alpha and H-beta). H-alpha line profiles during this event show some blue asymmetries. In this event, we also detected soft X-ray intensity increases, but a bit strangely and a bit different from previous expectations, the photometric data (optical continuum white light data) show no clear flare-like brightness increases. This might suggest that these intensity increases of chromospheric lines (with possible blue asymmetries) and soft X-rays occurred as a "non white-light" flare events, which are often seen in the case of solar flares (e.g., Watanabe et al. 2017). We also observed another M-dwarf flare star AU Mic using CTIO/SMART1.5m/CHIRON (high-dispersion spectroscopy), LCO (U&V-band photometry), and XMM-Newton (soft X-ray), and detected several flares in Oct 2018. In contrast to the above "non-white light" events, these flares show enhancements in Balmer lines (e.g., H-alpha), optical continuum white light, and soft X-ray. Then this event is a so-called "white-light" flare. Moreover, this "white-light" event does not show clear blue asymmetries, which are different from the above YZCMi "non-white light" event. In this poster, we introduce ongoing results on the analyses of these two events. Title: Stellar Properties of Active G and K Stars: Exploring the Connection between Starspots and Chromospheric Activity Authors: Morris, Brett M.; Curtis, Jason L.; Sakari, Charli; Hawley, Suzanne L.; Agol, Eric Bibcode: 2019AJ....158..101M Altcode: 2019arXiv190700423M We gathered high resolution spectra for an ensemble of 55 bright active and inactive stars using the ARC 3.5 m Telescope Echelle Spectrograph at Apache Point Observatory (R ≈ 31,500). We measured spectroscopic effective temperatures, surface gravities, and metallicities for most stars in the sample with SME and MOOG. Our stellar property results are consistent with the photometric effective temperatures from the Gaia DR2 pipeline. We also measured their chromospheric S and {log}{R}HK}{\prime } indices to classify the stars as active or inactive and study the connection between chromospheric activity and starspots. We then inferred the starspot covering fractions on the active stars by modeling their spectra as a linear combination of hot and cool inactive stellar spectral templates. We find that it is critical to use precise colors of the stars to place stringent priors on the plausible spot covering fractions. The inferred spot covering fractions generally increase with the chromospheric activity indicator {log}{R}HK}{\prime }, though we are largely insensitive to spot coverages smaller than f S ≲ 20%. We find a dearth of stars with small {log}{R}HK}{\prime } and significant spot coverages. Title: Measurements of the Ultraviolet Spectral Characteristics of Low-mass Exoplanetary Systems (Mega-MUSCLES) Authors: Wilson, David John; Froning, Cynthia; France, Kevin; Youngblood, Allison; Duvvuri, Girish M.; Brown, Alexander; Schneider, P. Christian; Kowalski, Adam; Loyd, R. O. Parke; Berta-Thompson, Zachory Berta-; Pineda, J. Sebastian; Linsky, Jeffrey; Rugheimer, Sarah; Newton, Elizabeth; Miguel, Yamila; Roberge, Aki; Buccino, Andrea P.; Irwin, Jonathan; Kaltenegger, Lisa; Vieytes, Mariela; Mauas, Pablo; Redfield, Seth; Hawley, Suzanne; Tian, Feng Bibcode: 2019ESS.....431906W Altcode: M dwarf stars have emerged as ideal targets for exoplanet observations. Their small radii aids planetary discovery, their close-in habitable zones allow short observing campaigns, and their red spectra provide opportunities for transit spectroscopy with JWST. The potential of M dwarfs has been underlined by the discovery of remarkable systems such as the seven Earth-sized planets orbiting TRAPPIST-1 and the habitable-zone planet around the closest star to the Sun.

However, to accurately assess the conditions in these systems requires a firm understanding of how M dwarfs differ from the Sun, beyond just their smaller size and mass. Of particular importance are the time-variable, high-energy ultraviolet and x-ray regions of the M dwarf spectral energy distribution (SED), which can influence the chemistry and lifetime of exoplanet atmospheres, as well as their surface radiation environments.

The Measurements of the Ultraviolet Spectral Characteristics of Low-mass Exoplanetary Systems (Mega-MUSCLES) Treasury project, together with the precursor MUSCLES project, aims to produce full SEDs of a representative sample of M dwarfs, covering a wide range of stellar mass, age, and planetary system architecture. We have obtained x-ray and ultraviolet data for 13 stars using the Hubble, Chandra and XMM space telescopes, along with ground-based data in the optical and state-of-the-art DEM modelling to fill in the unobservable extreme ultraviolet regions. Our completed SEDs will be available as a community resource, with the aim that a close MUSCLES analogue should exist for most M dwarfs of interest.

In this presentation I will overview the Mega-MUSCLES project, describing our choice of targets, observation strategy and SED production methodology. I will also discuss notable targets such as the TRAPPIST-1 host star, comparing our observations with previous data and model predictions. Finally, I will present an exciting by-product of the Mega-MUSCLES project: time-resolved ultraviolet spectroscopy of stellar flares at multiple targets, spanning a range of stellar types, ages and flare energies. Title: The Mysterious Activity of TRAPPIST-1 Authors: Morris, Brett; Agol, Eric; Davenport, James; Hawley, Suzanne Bibcode: 2019ESS.....433311M Altcode: TRAPPIST-1 is one of the most tantalizing exoplanet systems discovered to date, with seven Earth-sized transiting exoplanets in a resonant chain orbiting an ultra-cool dwarf star. To make robust inferences about the properties of the exoplanets orbiting TRAPPIST-1, we must first identify any stellar surface inhomogeneities which will confound exoplanet transmission spectroscopy (Morris et al. 2018, Rackham et al. 2018, Ducrot et al. 2018). TRAPPIST-1 is the first M8V star to be scrutinized with long-term 1% precision photometry in multiple wavebands, and preliminary analyses of the surface features of the host star are full of surprises. There is no definitive evidence for coverage of the stellar surface by dark starspots, but there is photometric and spectroscopic evidence for bright, hot regions on the surface of the star. Furthermore, the occurence of flares seems to be correlated with the optical flux of the star, perhaps suggesting that the apparent rotational modulation of the star could instead be evolution of bright active regions. We will discuss the available evidence for activity and rotation of the host star, and conclude with a discussion of the implications for transmission spectroscopy of the exoplanets. Title: Do Kepler superflare stars really include slowly-rotating Sun-like stars ? - Results using APO 3.5m telescope spectroscopic observations and Gaia-DR2 data - Authors: Notsu, Yuta; Maehara, Hiroyuki; Honda, Satoshi; Hawley, Suzanne L.; Davenport, James R. A.; Namekata, Kosuke; Notsu, Shota; Ikuta, Kai; Nogami, Daisaku; Shibata, Kazunari Bibcode: 2019AAS...23412202N Altcode: Solar and stellar flares are the energetic explosions in the solar and stellar atmosphere, and superflares are very large flares that release total energy 10∼104 times greater than that of the biggest solar flares (∼1032 erg). Recent Kepler-space-telescope observations found more than 1000 superflares on a few hundred solar-type stars. We report the latest view of Kepler solar-type (G-type main-sequence) superflare stars, including recent updates with Apache Point Observatory (APO) 3.5m telescope spectroscopic observations and Gaia-DR2 data. First, more than half (43 stars) are confirmed to be "single" stars, among 64 superflare stars in total that have been spectroscopically investigated so far in this APO3.5m and our previous Subaru/HDS observations. The measurements of v sin i (projected rotational velocity) and chromospheric lines (Ca II H&K and Ca II 8542 A) support the brightness variation of superflare stars is caused by the rotation of a star with large starspots. Then, we investigated again the statistical properties of Kepler solar- type superflare stars by incorporating Gaia-DR2 stellar radius values. As a result, the maximum superflare energy continuously decreases as the rotation period Prot increases. Superflares with their energy < 5×1034 erg would occur on old slowly-rotating Sun-like stars (Prot ∼25 days) once every 2000-3000 years, while young rapidly- rotating stars with Prot ∼ a few days have superflares up to 1036 erg. The maximum starspot area does not depend on the rotation period when the star is young rapidly- rotating, but as the rotation slows down, it starts to steeply decrease at Prot 12 days for Sun-like stars. These two decreasing trends can be consistent since the magnetic energy stored around starspots explains the flare energy, but other factors like spot magnetic structure should be also considered. These results presented in this work support that even slowly-rotating stars similar to the Sun can have large starspots necessary for superflares, considering long-term (1,000-10,000 years) activity level changes. Title: Lifetimes and emergence/decay rates of star spots on solar-type stars estimated by Kepler data in comparison with those of sunspots Authors: Namekata, Kosuke; Maehara, H.; Davenport, J.; Morris, B.; Hawley, S.; Notsu, Y.; Toriumi, S.; Hayakawa, H.; Honda, S.; Notsu, S.; Ikuta, K.; Nogami, D.; Shibata, K. Bibcode: 2019shin.confE..42N Altcode: Active solar-type stars show large quasi-periodic brightness variations caused by stellar rotations with large star spots, and the amplitude change as the spots emerge and decay. Temporal evolution of star spots has been hardly measured because of its difficulty in measurement, especially on solar-type stars. The Kepler’s long-term data is suitable for investigations on the emergence and decay processes of star spots, which are important to understand underlying stellar dynamo. In this talk, we report the measurements of temporal evolution of individual star-spot area on solar-type stars by using Kepler data. We estimated it (i) by tracing local minima of the Kepler light curves (Namekata et al. 2019) and (ii) by modeling the small brightness variation during exoplanet transit (c.f. Morris et al. 2017, Namekata et al. in prep). We successfully obtained temporal evolution of individual star spots showing clear emergence and decay, and derived the statistical values of the lifetimes and emergence/decay rates of star spots. As a result, we found that lifetimes (T) of star spots are ranging from 10 to 350 days when spot areas (A) are 0.1-2.3% of a solar hemisphere (SH). The lifetimes of star spots are much shorter than those extrapolated from an empirical relation of sunspots, while being consistent with other researches on star spot lifetimes. The emerging and decay rates of star spots are typically 5×10^20 Mx/h (8 MSH/h) with the area of 0.1-2.3% of SH and are mostly consistent with those expected from sunspots observations (Petrovay et al. 1997, Norton et al. 2017). This strongly supports a possibility that the emergence/decay mechanism of extremely large star spots (0.1-2.3% of SH) is same as that of smaller sunspots (<0.5% of SH), which can constrain the stellar dynamo theory. Title: Do Kepler Superflare Stars Really Include Slowly Rotating Sun-like Stars?—Results Using APO 3.5 m Telescope Spectroscopic Observations and Gaia-DR2 Data Authors: Notsu, Yuta; Maehara, Hiroyuki; Honda, Satoshi; Hawley, Suzanne L.; Davenport, James R. A.; Namekata, Kosuke; Notsu, Shota; Ikuta, Kai; Nogami, Daisaku; Shibata, Kazunari Bibcode: 2019ApJ...876...58N Altcode: 2019arXiv190400142N We report the latest view of Kepler solar-type (G-type main-sequence) superflare stars, including recent updates with Apache Point Observatory (APO) 3.5 m telescope spectroscopic observations and Gaia-DR2 data. First, we newly conducted APO 3.5 m spectroscopic observations of 18 superflare stars found from Kepler 1-minute time-cadence data. More than half (43 stars) are confirmed to be “single” stars, among 64 superflare stars in total that have been spectroscopically investigated so far in this APO 3.5 m and our previous Subaru/HDS observations. The measurements of v sin i (projected rotational velocity) and chromospheric lines (Ca II H and K and Ca II λ8542) support that the brightness variation of superflare stars is caused by the rotation of a star with large starspots. We then investigated the statistical properties of Kepler solar-type superflare stars by incorporating Gaia-DR2 stellar radius estimates. As a result, the maximum superflare energy continuously decreases as the rotation period P rot increases. Superflares with energies ≲5 × 1034 erg occur on old, slowly rotating Sun-like stars (P rot ∼ 25 days) approximately once every 2000-3000 yr, while young, rapidly rotating stars with P rot ∼ a few days have superflares up to 1036 erg. The maximum starspot area does not depend on the rotation period when the star is young, but as the rotation slows down, it starts to steeply decrease at P rot ≳ 12 days for Sun-like stars. These two decreasing trends are consistent since the magnetic energy stored around starspots explains the flare energy, but other factors like spot magnetic structure should also be considered. Title: Do superflares really occur on slowly-rotating Sun-like stars in the long-term activity changes? -- Latest statistical results using Kepler and Gaia-DR2 data - Authors: Notsu, Yuta; Maehara, Hiroyuki; Honda, Satoshi; Hawley, Suzanne L.; Davenport, James R. A.; Namekata, Kosuke; Notsu, Shota; Ikuta, Kai; Nogami, Daisaku; Shibata, Kazunari Bibcode: 2019shin.confE..17N Altcode: Superflares are very large flares that release total energy 10-10^4 times greater than that of the biggest solar flares (?10^32 erg). Recent Kepler space telescope observations found more than 1000 superflares on a few hundred solar-type stars. Our previous statistical studies of these data suggested that superflares with energy up to 10^35 erg could occur on Sun-like slowly-rotating stars (Rotation period Prot ? 25 days) once in a few thousand years.

On the other hand, the recent Gaia-DR2 stellar radius data have suggested the possibility of severe contaminations of subgiant stars in the classification of Kepler solar-type (G-type main-sequence) stars used for the above previous studies.

Then in this new study (Notsu+2019, ApJ, 876, 58), we investigated again the statistical properties of Kepler solar-type superflare stars by incorporating Gaia-DR2 stellar radius values. More than 40% of the original solar-type superflare stars in our previous studies are now classified as subgiant stars and are rejected from the following statistical results. As a result, the maximum superflare energy continuously decreases as the Prot increases. Superflares with their energy 5 × 10^34 erg would occur on old slowly-rotating Sun-like stars (Prot ?25 days) once every 2000-3000 years. In contrast, superflares up to ?10^36 erg can occur on young rapidly-rotating stars (Prot ? a few days), and the flare frequency of such young rapidly-rotating stars is at least 100 times higher compared with the old slowly-rotating Sun-like stars. The maximum starspot area does not depend on the rotation period when the star is young rapidly-rotating, but as the rotation slows down, it starts to steeply decrease at Prot 12 days for Sun-like stars. These two decrease trends can be consistent since the magnetic energy stored around the starspots explains the flare energy, but other factors like spot magnetic structure should be also considered. Title: The solar benchmark: rotational modulation of the Sun reconstructed from archival sunspot records Authors: Morris, Brett M.; Davenport, James R. A.; Giles, Helen A. C.; Hebb, Leslie; Hawley, Suzanne L.; Angus, Ruth; Gilman, Peter A.; Agol, Eric Bibcode: 2019MNRAS.484.3244M Altcode: 2019arXiv190104557M; 2019MNRAS.tmp..205M We use archival daily spot coverage measurements from Howard et al. to study the rotational modulation of the Sun as though it were a distant star. A quasi-periodic Gaussian process measures the solar rotation period Prot = 26.3 ± 0.1 d, and activity cycle period Pcyc = 10.7 ± 0.3 yr. We attempt to search for evidence of differential rotation in variations of the apparent rotation period throughout the activity cycle and do not detect a clear signal of differential rotation, consistent with the null results of the hare-and-hounds exercise of Aigrain et al. The full reconstructed solar light curve is available online. Title: The Evolution of Flare Activity with Stellar Age Authors: Davenport, James R. A.; Covey, Kevin R.; Clarke, Riley W.; Boeck, Austin C.; Cornet, Jonathan; Hawley, Suzanne L. Bibcode: 2019ApJ...871..241D Altcode: 2019arXiv190100890D Using a recent census of flare stars from the Kepler survey, we have explored how flare activity evolves across stellar main-sequence lifetimes. We utilize a sample of 347 stars with robust flare activity detections and which have rotation periods measured via starspot modulations in their Kepler light curves. We consider three separate methods for quantifying flare activity from optical light curves and compare their utility for comparing flare activity between stars of differing ages and luminosities. These metrics include the fractional luminosity emitted in flares, the specific rate of flares emitted at a given energy, and a model for the entire flare frequency distribution (FFD). With all three approaches, we find that flare activity decreases for all low-mass stars as they spin down, and thus with age. Most striking is the evolution of the flare occurrence frequency distributions, which show no significant change in the power-law slope with age. Since our sample is preferentially constructed of younger, more active stars, our model overpredicts the superflare rate previously estimated for the Sun. Finally, we parameterize our best-fit model of the FFD for ease in predicting the rates of flares and their associated impacts on planet habitability and detection. Title: The Near-ultraviolet Continuum Radiation in the Impulsive Phase of HF/GF-type dMe Flares. I. Data Authors: Kowalski, Adam F.; Wisniewski, John P.; Hawley, Suzanne L.; Osten, Rachel A.; Brown, Alexander; Fariña, Cecilia; Valenti, Jeff A.; Brown, Stephen; Xilouris, Manolis; Schmidt, Sarah J.; Johns-Krull, Christopher Bibcode: 2019ApJ...871..167K Altcode: 2018arXiv181104021K We present near-UV (NUV) flare spectra from the Hubble Space Telescope (HST)/Cosmic Origins Spectrograph during two moderate-amplitude U-band flares on the dM4e star GJ 1243. These spectra are some of the first accurately flux-calibrated, NUV flare spectra obtained over the impulsive phase in M dwarf flares. We observed these flares with a fleet of nine ground-based telescopes simultaneously, which provided broadband photometry and low-resolution spectra at the Balmer jump. An increase in the broadband continuum occurred with a signal-to-noise ratio >20 in the HST spectra, while numerous Fe II lines and the Mg II lines also increased but with smaller flux enhancements than the continuum radiation. These two events produced the most prominent Balmer line radiation and the largest Balmer jumps that have been observed to date in dMe flare spectra. A T = 9000 K blackbody underestimates the NUV continuum flare flux by a factor of two and is a poor approximation to the white light in these types of flare events. Instead, our data suggest that the peak of the specific continuum flux density is constrained to U-band wavelengths near the Balmer series limit. A radiative-hydrodynamic simulation of a very high energy deposition rate averaged over times of impulsive heating and cooling better explains the properties of the λ > 2500 Å flare continuum. These two events sample only one end of the empirical color-color distribution for dMe flares, and more time-resolved flare spectra in the NUV, U band, and optical from 2000 to 4200 Å are needed during more impulsive and/or more energetic flares. Title: Towards space-quality photometry from the ground with beam-shaping diffusers for K2, TESS and Beyond. Authors: Stefansson, Gudmundur K.; Mahadevan, Suvrath; Wisniewski, John; Morris, Brett M.; Hebb, Leslie; Maney, Marissa; Li, Yiting; Monson, Andrew; Robertson, Paul; Huehnerhoff, Joseph; Hawley, Suzanne Bibcode: 2019AAS...23321512S Altcode: Precision ground-based photometry plays a key role in discovering and characterizing transiting exoplanet candidates. Using custom-fabricated beam-shaping diffusers, we demonstrate a path to achieving some of the highest differential photometric precisions from the ground. These diffusers are micro-structured optical components capable of molding the image of a star into a broad and stable top-hat shape, minimizing photometric errors due to non-uniform pixel response, atmospheric seeing effects, and telescope-induced variable aberrations seen in defocusing. I discuss our efforts in commissioning an optical diffuser on the ARC 3.5m Telescope at Apache Point Observatory demonstrating 62ppm precision in 30 minute bins—some of the highest photometric precisions from the ground. I will present our current results from our ongoing ground-based follow-up program to follow up K2 and soon-to-come TESS candidates. Being inexpensive and easily adaptable, I will highlight some of our ongoing efforts to install beam-shaping diffusers on other telescopes large and small. Title: Modeling Repeated M Dwarf Flaring at an Earth-like Planet in the Habitable Zone: Atmospheric Effects for an Unmagnetized Planet Authors: Tilley, Matt A.; Segura, Antígona; Meadows, Victoria; Hawley, Suzanne; Davenport, James Bibcode: 2019AsBio..19...64T Altcode: No abstract at ADS Title: Diffuser-assisted Photometric Follow-up Observations of the Neptune-sized Planets K2-28b and K2-100b Authors: Stefansson, Gudmundur; Li, Yiting; Mahadevan, Suvrath; Wisniewski, John; Hebb, Leslie; Morris, Brett; Huehnerhoff, Joseph; Hawley, Suzanne Bibcode: 2018AJ....156..266S Altcode: 2018arXiv180704420S We present precision transit observations of the Neptune-sized planets K2-28b and K2-100b using the Engineered Diffuser on the Astrophysical Research Council Telescope Imaging Camera (ARCTIC) imager on the ARC 3.5 m Telescope at Apache Point Observatory. K2-28b is a R p = 2.56 R ⊕ mini-Neptune transiting a bright (J = 11.7) metal-rich M4 dwarf offering compelling prospects for future atmospheric characterization. K2-100b is an R p = 3.45 R ⊕ Neptune in the Praesepe Cluster and is one of few planets known in a cluster transiting a host star bright enough (V = 10.5) for precision radial velocity observations. Using the precision photometric capabilities of the diffuser/ARCTIC system allows us to achieve a precision of 365 ppm and 70 ppm in 30-minute bins for K2-28b and K2-100b, respectively. Our joint-fits to the K2 and ground-based light curves give an order-of-magnitude improvement in the orbital ephemeris for both planets, yielding a timing precision of 2 minutes in the James Webb Space Telescope (JWST) era. Although we show that the currently available broad-band measurements of K2-28b’s radius are currently too imprecise to place useful constraints on K2-28b’s atmosphere, we demonstrate that JWST/NIRISS will be able to discern between a cloudy/clear atmosphere in a modest number of transit observations. Our light curve of K2-100b marks the first transit follow-up observation of this challenging-to-observe transit, where we obtain a transit depth of 822 ± 50 ppm in the SDSS i‧ band. We conclude that diffuser-assisted photometry can play an important role in the Transiting Exoplanet Survey Satellite (TESS) era to perform timely and precise follow-up of the expected bounty of TESS planet candidates. Title: Are Starspots and Plages Co-located on Active G and K Stars? Authors: Morris, Brett M.; Curtis, Jason L.; Douglas, Stephanie T.; Hawley, Suzanne L.; Agüeros, Marcel A.; Bobra, Monica G.; Agol, Eric Bibcode: 2018AJ....156..203M Altcode: 2018arXiv180904522M We explore the connection between starspots and plages of three main-sequence stars by studying the chromospheric and photospheric activity over several rotation periods. We present simultaneous photometry and high-resolution (R ∼ 31500) spectroscopy of KIC 9652680, a young, super-flare-producing G1 star with a rotation period of 1.4 days. Its Kepler light curve shows rotational modulation consistent with a bright hemisphere followed by a relatively dark hemisphere, generating photometric variability with a semi-amplitude of 4%. We find that KIC 9652680 is darkest when its S-index of Ca II H & K emission is at its maximum. We interpret this anti-correlation between flux and S to indicate that dark starspots in the photosphere are co-located with the bright plages in the chromosphere, as they are on the Sun. Moving to lower masses and slower rotators, we present K2 observations with simultaneous spectroscopy of EPIC 211928486 (K5V) and EPIC 211966629 (K4V), two active stars in the 650 Myr old open cluster Praesepe. The K2 photometry reveals that both stars have rotation periods of 11.7 days; while their flux varies by 1 and 2% respectively, their Ca II H & K S-indices seem to hold relatively constant as a function of rotational phase. This suggests that extended chromospheric networks of plages are not concentrated into regions of emission centered on the starspots that drive rotational modulation, unlike KIC 9652680. We also note that the Ca II emission of EPIC 211928486 dipped and recovered suddenly over the duration of one rotation, suggesting that the evolution timescale of plages may be of order the rotation period. Title: Robust Transiting Exoplanet Radii in the Presence of Starspots from Ingress and Egress Durations Authors: Morris, Brett M.; Agol, Eric; Hebb, Leslie; Hawley, Suzanne L. Bibcode: 2018AJ....156...91M Altcode: 2018arXiv180704886M We typically measure the radii of transiting exoplanets from the transit depth, which are given by the ratio of cross-sectional areas of the planet and star. However, if a star has dark starspots (or bright regions) distributed throughout the transit chord, the transit depth will be biased toward smaller (larger) values, and thus the inferred planet radius will be smaller (larger) if these are unaccounted for. We reparameterize the transit light curve to account for “self-contamination” by photospheric inhomogeneities by splitting the parameter R p /R ⋆ into two parameters: one for the radius ratio, which controls the duration of ingress and egress, and another which measures the possibly contaminated transit depth. We show that this is equivalent to the formulation for contamination by a second star (with positive or negative flux), and that it is sensitive to time-steady inhomogeneity of the stellar photosphere. We use synthetic light curves of spotted stars at high signal-to-noise to show that the radius recovered from measurement of the ingress/egress duration can recover the true radii of planets transiting spotted stars with axisymmetric spot distributions if the limb-darkening parameters are precisely known. We fit time-averaged high signal-to-noise transit light curves from Kepler and Spitzer of 10 planets to measure the planet radii and search for evidence of spot distributions. We find that this sample has a range of measured depths and ingress durations that are self-consistent, providing no strong evidence for contamination by spots. However, there is suggestive evidence for occultation of starspots on Kepler-17, and that relatively bright regions are occulted by the planets of Kepler-412 and HD 80606. Future observations with the James Webb Space Telescope may enable this technique to yield accurate planetary radii in the presence of stellar inhomogeneities. Title: VizieR Online Data Catalog: Kepler EB classifications and rotation periods (Lurie+, 2017) Authors: Lurie, J. C.; Vyhmeister, K.; Hawley, S. L.; Adilia, J.; Chen, A.; Davenport, J. R. A.; Juric, M.; Puig-Holzman, M.; Weisenburger, K. L. Bibcode: 2018yCat..51540250L Altcode: We began with the 2863 targets in the Kepler Eclipsing Binary Catalog (KEBC, http://keplerebs.villanova.edu, Prsa et al. 2011, J/AJ/141/83; Slawson et al. 2011, J/AJ/142/160; Kirk et al. 2016, J/AJ/151/68), downloaded on 2017 March 24. The KEBC includes orbital periods, ephemerides, and primary and secondary (when detected) eclipse depths, widths, and phase separations. After exclusions, there were 2278 EBs remaining that we analyzed. Our analysis involved two steps. First, we visually inspected the light curves to classify EBs with starspot modulations, as well as other types of EBs. Next, we measured rotation periods for the 816 EBs with starspot modulations using the following procedure. First, we linearly interpolated over eclipses, and then measured initial rotation periods using the autocorrelation function (ACF, see McQuillan et al. 2013, J/MNRAS/432/1203).

(1 data file). Title: Non-detection of Contamination by Stellar Activity in the Spitzer Transit Light Curves of TRAPPIST-1 Authors: Morris, Brett M.; Agol, Eric; Hebb, Leslie; Hawley, Suzanne L.; Gillon, Michaël; Ducrot, Elsa; Delrez, Laetitia; Ingalls, James; Demory, Brice-Olivier Bibcode: 2018ApJ...863L..32M Altcode: 2018arXiv180802808M We apply the transit light curve self-contamination technique of Morris et al. to search for the effect of stellar activity on the transits of the ultracool dwarf TRAPPIST-1 with 2018 Spitzer photometry. The self-contamination method fits the transit light curves of planets orbiting spotted stars, allowing the host star to be a source of contaminating positive or negative flux that influences the transit depths but not the ingress/egress durations. We find that none of the planets show statistically significant evidence for self-contamination by bright or dark regions of the stellar photosphere. However, we show that small-scale magnetic activity, analogous in size to the smallest sunspots, could still be lurking undetected in the transit photometry. Title: Spectroscopic observations of Kepler/TESS solar-type supeflare stars Authors: Notsu, Yuta; Maehara, Hiroyuki; Honda, Satoshi; Hawley, Suzanne; Davenport, James; Notsu, Shota; Namekata, Kosuke; Ikuta, Kai; Nogami, Daisaku; Shibata, Kazunari Bibcode: 2018csss.confE..14N Altcode: Recent Kepler-space-telescope observations found more than 1000 superflares on 300 solar-type stars (e.g., Maeahra+2012 Nature; Shibayama+2013 ApJS). Many of the superflare stars show quasi-periodic brightness variations with the typical period of 1-30 days and the typical amplitude of 0.1-10 percent. We conducted spectroscopic observations of these superflare stars using Subaru/HDS and APO 3.5m telescope (Notsu+2015a&b, 2018 in prep). The projected rotation velocity (v sin i) values are consistent with brightness variation period, and there is a good correlation between Kepler brightness variation amplitude and the intensity of Ca II lines (Ca II H&K, Ca II 8542Å). These results support that the above brightness variations are caused by stellar rotation with large starspots, and existence of large starspots should be a key to understand superflares.More detailed spectroscopic studies (e.g., activity cycle) of superflare stars are important, but Kepler target stars are faint and not appropriate for such detailed studies. TESS satellite, launched in April 2018, brings us a large sample of brighter (e.g., V < 12 mag) superflare stars. We have started spectroscopic monitoring observations of nearby active solar-type stars (superflare candidate stars) in the TESS field. These results can have good collaborations with multi-wavelength project observations (e.g., X-ray, UV, polarimetry) of young solar-type stars. Title: The Evolution of T = 10,000 K Blackbody-Like Continuum Radiation in the Impulsive Phase of dMe Flares Authors: Kowalski, Adam F.; Mathioudakis, Mihalis; Hawley, Suzanne L. Bibcode: 2018csss.confE..42K Altcode: 2018arXiv181007226K The near-ultraviolet and optical (white-light) continuum radiation in M dwarf flares exhibits a range of observed characteristics, suggesting that the amount of heating at large optical depth varies among impulsive-type and gradual-type flares. Specific flux ratios from high-time cadence spectra and narrowband continuum photometry have also shown that these characteristics vary from the peak to the gradual decay phases of flares. In these proceedings, we present the highest-time cadence ( 1 s), highest signal-to-noise ( 100) constraints on the optical color temperature evolution during the rise phase of a large, impulsive-type dMe flare event. The flare exhibits compelling evidence of a hot, color temperature (T 10,000 K), but the Balmer jump ratios show that the flare cannot be explained by isothermal slabs or blackbody surfaces at any time in the evolution. The new data analysis establish these properties as critical challenges for any flare model, and we discuss 1D radiative-hydrodynamic modeling that will be compared to the evolution of the flare colors in this intriguing event. Title: Structure in the Disk of epsilon Aurigae -- Analysis of ARCES and TripleSpec data from the 2010 eclipse Authors: Gibson, Justus; Stencel, Robert E.; ARCES Team; Ketzeback, W.; Barentine, J.; Bradley, A.; Coughlin, J.; Dembicky, J.; Hawley, S.; Huehnerhoff, J.; Leadbeater, R.; McMillan, R.; Saurage, G.; Schmidt, S.; Ule, N.; Wallerstein, G.; York, D. Bibcode: 2018AAS...23231501G Altcode: Worldwide interest in the recent eclipse of epsilon Aurigae resulted in the generation of several extensive data sets, including high resolution spectroscopic monitoring. This lead to the discovery, among other things, of the existence of a mass transfer stream, seen notably during third contact. We explored spectroscopic facets of the mass transfer stream during third contact, using high resolution spectra obtained with the ARCES and TripleSpec instruments at Apache Point Observatory. One hundred and sixteen epochs of data were obtained between 2009 and 2012, and equivalent widths and line velocities measured for high versus low eccentricity accretion disk lines. These datasets also enable greater detail to be measured of the mid-eclipse enhancement of the He I 10830A line, and the discovery of the P Cygni shape of the Pa-beta line at third contact. We found evidence of higher speed material, associated with the mass transfer stream, persisting between third and fourth eclipse contacts. We visualized the disk and stream interaction using SHAPE software, and used CLOUDY software to estimate that the source of the enhanced He I 10830A absorption arises from a region with log nH = 11 cm-3 and temperature of 20,000 K, consistent with a mid-B type central star. We thank the following for their contributions to this paper: William Ketzeback, John Barentine, Jeffrey Coughlin, Robin Leadbeater, Gabrelle Saurage, and others. This paper has been submitted to Monthly Notices. Title: Spotting stellar activity cycles in Gaia astrometry Authors: Morris, Brett M.; Agol, Eric; Davenport, James R. A.; Hawley, Suzanne L. Bibcode: 2018MNRAS.476.5408M Altcode: 2018MNRAS.tmp..549M; 2018arXiv180209943M Astrometry from Gaia will measure the positions of stellar photometric centroids to unprecedented precision. We show that the precision of Gaia astrometry is sufficient to detect starspot-induced centroid jitter for nearby stars in the Tycho-Gaia Astrometric Solution (TGAS) sample with magnetic activity similar to the young G-star KIC 7174505 or the active M4 dwarf GJ 1243, but is insufficient to measure centroid jitter for stars with Sun-like spot distributions. We simulate Gaia observations of stars with 10 year activity cycles to search for evidence of activity cycles, and find that Gaia astrometry alone likely cannot detect activity cycles for stars in the TGAS sample, even if they have spot distributions like KIC 7174505. We review the activity of the nearby low-mass stars in the TGAS sample for which we anticipate significant detections of spot-induced jitter. Title: Possible Bright Starspots on TRAPPIST-1 Authors: Morris, Brett M.; Agol, Eric; Davenport, James R. A.; Hawley, Suzanne L. Bibcode: 2018ApJ...857...39M Altcode: 2018arXiv180304543M The M8V star TRAPPIST-1 hosts seven roughly Earth-sized planets and is a promising target for exoplanet characterization. Kepler/K2 Campaign 12 observations of TRAPPIST-1 in the optical show an apparent rotational modulation with a 3.3-day period, though that rotational signal is not readily detected in the Spitzer light curve at 4.5 μm. If the rotational modulation is due to starspots, persistent dark spots can be excluded from the lack of photometric variability in the Spitzer light curve. We construct a photometric model for rotational modulation due to photospheric bright spots on TRAPPIST-1 that is consistent with both the Kepler and Spitzer light curves. The maximum-likelihood model with three spots has typical spot sizes of R spot/R ⋆ ≈ 0.004 at temperature T spot ≳ 5300 ± 200 K. We also find that large flares are observed more often when the brightest spot is facing the observer, suggesting a correlation between the position of the bright spots and flare events. In addition, these flares may occur preferentially when the spots are increasing in brightness, which suggests that the 3.3-day periodicity may not be a rotational signal, but rather a characteristic timescale of active regions. Title: The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the Extended Baryon Oscillation Spectroscopic Survey and from the Second Phase of the Apache Point Observatory Galactic Evolution Experiment Authors: Abolfathi, Bela; Aguado, D. S.; Aguilar, Gabriela; Allende Prieto, Carlos; Almeida, Andres; Ananna, Tonima Tasnim; Anders, Friedrich; Anderson, Scott F.; Andrews, Brett H.; Anguiano, Borja; Aragón-Salamanca, Alfonso; Argudo-Fernández, Maria; Armengaud, Eric; Ata, Metin; Aubourg, Eric; Avila-Reese, Vladimir; Badenes, Carles; Bailey, Stephen; Balland, Christophe; Barger, Kathleen A.; Barrera-Ballesteros, Jorge; Bartosz, Curtis; Bastien, Fabienne; Bates, Dominic; Baumgarten, Falk; Bautista, Julian; Beaton, Rachael; Beers, Timothy C.; Belfiore, Francesco; Bender, Chad F.; Bernardi, Mariangela; Bershady, Matthew A.; Beutler, Florian; Bird, Jonathan C.; Bizyaev, Dmitry; Blanc, Guillermo A.; Blanton, Michael R.; Blomqvist, Michael; Bolton, Adam S.; Boquien, Médéric; Borissova, Jura; Bovy, Jo; Bradna Diaz, Christian Andres; Brandt, William Nielsen; Brinkmann, Jonathan; Brownstein, Joel R.; Bundy, Kevin; Burgasser, Adam J.; Burtin, Etienne; Busca, Nicolás G.; Cañas, Caleb I.; Cano-Díaz, Mariana; Cappellari, Michele; Carrera, Ricardo; Casey, Andrew R.; Cervantes Sodi, Bernardo; Chen, Yanping; Cherinka, Brian; Chiappini, Cristina; Choi, Peter Doohyun; Chojnowski, Drew; Chuang, Chia-Hsun; Chung, Haeun; Clerc, Nicolas; Cohen, Roger E.; Comerford, Julia M.; Comparat, Johan; Correa do Nascimento, Janaina; da Costa, Luiz; Cousinou, Marie-Claude; Covey, Kevin; Crane, Jeffrey D.; Cruz-Gonzalez, Irene; Cunha, Katia; da Silva Ilha, Gabriele; Damke, Guillermo J.; Darling, Jeremy; Davidson, James W., Jr.; Dawson, Kyle; de Icaza Lizaola, Miguel Angel C.; de la Macorra, Axel; de la Torre, Sylvain; De Lee, Nathan; de Sainte Agathe, Victoria; Deconto Machado, Alice; Dell'Agli, Flavia; Delubac, Timothée; Diamond-Stanic, Aleksandar M.; Donor, John; Downes, Juan José; Drory, Niv; du Mas des Bourboux, Hélion; Duckworth, Christopher J.; Dwelly, Tom; Dyer, Jamie; Ebelke, Garrett; Davis Eigenbrot, Arthur; Eisenstein, Daniel J.; Elsworth, Yvonne P.; Emsellem, Eric; Eracleous, Michael; Erfanianfar, Ghazaleh; Escoffier, Stephanie; Fan, Xiaohui; Fernández Alvar, Emma; Fernandez-Trincado, J. G.; Fernando Cirolini, Rafael; Feuillet, Diane; Finoguenov, Alexis; Fleming, Scott W.; Font-Ribera, Andreu; Freischlad, Gordon; Frinchaboy, Peter; Fu, Hai; Gómez Maqueo Chew, Yilen; Galbany, Lluís; García Pérez, Ana E.; Garcia-Dias, R.; García-Hernández, D. A.; Garma Oehmichen, Luis Alberto; Gaulme, Patrick; Gelfand, Joseph; Gil-Marín, Héctor; Gillespie, Bruce A.; Goddard, Daniel; González Hernández, Jonay I.; Gonzalez-Perez, Violeta; Grabowski, Kathleen; Green, Paul J.; Grier, Catherine J.; Gueguen, Alain; Guo, Hong; Guy, Julien; Hagen, Alex; Hall, Patrick; Harding, Paul; Hasselquist, Sten; Hawley, Suzanne; Hayes, Christian R.; Hearty, Fred; Hekker, Saskia; Hernandez, Jesus; Hernandez Toledo, Hector; Hogg, David W.; Holley-Bockelmann, Kelly; Holtzman, Jon A.; Hou, Jiamin; Hsieh, Bau-Ching; Hunt, Jason A. S.; Hutchinson, Timothy A.; Hwang, Ho Seong; Jimenez Angel, Camilo Eduardo; Johnson, Jennifer A.; Jones, Amy; Jönsson, Henrik; Jullo, Eric; Khan, Fahim Sakil; Kinemuchi, Karen; Kirkby, David; Kirkpatrick, Charles C., IV; Kitaura, Francisco-Shu; Knapp, Gillian R.; Kneib, Jean-Paul; Kollmeier, Juna A.; Lacerna, Ivan; Lane, Richard R.; Lang, Dustin; Law, David R.; Le Goff, Jean-Marc; Lee, Young-Bae; Li, Hongyu; Li, Cheng; Lian, Jianhui; Liang, Yu; Lima, Marcos; Lin, Lihwai; Long, Dan; Lucatello, Sara; Lundgren, Britt; Mackereth, J. Ted; MacLeod, Chelsea L.; Mahadevan, Suvrath; Maia, Marcio Antonio Geimba; Majewski, Steven; Manchado, Arturo; Maraston, Claudia; Mariappan, Vivek; Marques-Chaves, Rui; Masseron, Thomas; Masters, Karen L.; McDermid, Richard M.; McGreer, Ian D.; Melendez, Matthew; Meneses-Goytia, Sofia; Merloni, Andrea; Merrifield, Michael R.; Meszaros, Szabolcs; Meza, Andres; Minchev, Ivan; Minniti, Dante; Mueller, Eva-Maria; Muller-Sanchez, Francisco; Muna, Demitri; Muñoz, Ricardo R.; Myers, Adam D.; Nair, Preethi; Nandra, Kirpal; Ness, Melissa; Newman, Jeffrey A.; Nichol, Robert C.; Nidever, David L.; Nitschelm, Christian; Noterdaeme, Pasquier; O'Connell, Julia; Oelkers, Ryan James; Oravetz, Audrey; Oravetz, Daniel; Ortíz, Erik Aquino; Osorio, Yeisson; Pace, Zach; Padilla, Nelson; Palanque-Delabrouille, Nathalie; Palicio, Pedro Alonso; Pan, Hsi-An; Pan, Kaike; Parikh, Taniya; Pâris, Isabelle; Park, Changbom; Peirani, Sebastien; Pellejero-Ibanez, Marcos; Penny, Samantha; Percival, Will J.; Perez-Fournon, Ismael; Petitjean, Patrick; Pieri, Matthew M.; Pinsonneault, Marc; Pisani, Alice; Prada, Francisco; Prakash, Abhishek; Queiroz, Anna Bárbara de Andrade; Raddick, M. Jordan; Raichoor, Anand; Barboza Rembold, Sandro; Richstein, Hannah; Riffel, Rogemar A.; Riffel, Rogério; Rix, Hans-Walter; Robin, Annie C.; Rodríguez Torres, Sergio; Román-Zúñiga, Carlos; Ross, Ashley J.; Rossi, Graziano; Ruan, John; Ruggeri, Rossana; Ruiz, Jose; Salvato, Mara; Sánchez, Ariel G.; Sánchez, Sebastián F.; Sanchez Almeida, Jorge; Sánchez-Gallego, José R.; Santana Rojas, Felipe Antonio; Santiago, Basílio Xavier; Schiavon, Ricardo P.; Schimoia, Jaderson S.; Schlafly, Edward; Schlegel, David; Schneider, Donald P.; Schuster, William J.; Schwope, Axel; Seo, Hee-Jong; Serenelli, Aldo; Shen, Shiyin; Shen, Yue; Shetrone, Matthew; Shull, Michael; Silva Aguirre, Víctor; Simon, Joshua D.; Skrutskie, Mike; Slosar, Anže; Smethurst, Rebecca; Smith, Verne; Sobeck, Jennifer; Somers, Garrett; Souter, Barbara J.; Souto, Diogo; Spindler, Ashley; Stark, David V.; Stassun, Keivan; Steinmetz, Matthias; Stello, Dennis; Storchi-Bergmann, Thaisa; Streblyanska, Alina; Stringfellow, Guy S.; Suárez, Genaro; Sun, Jing; Szigeti, Laszlo; Taghizadeh-Popp, Manuchehr; Talbot, Michael S.; Tang, Baitian; Tao, Charling; Tayar, Jamie; Tembe, Mita; Teske, Johanna; Thakar, Aniruddha R.; Thomas, Daniel; Tissera, Patricia; Tojeiro, Rita; Tremonti, Christy; Troup, Nicholas W.; Urry, Meg; Valenzuela, O.; van den Bosch, Remco; Vargas-González, Jaime; Vargas-Magaña, Mariana; Vazquez, Jose Alberto; Villanova, Sandro; Vogt, Nicole; Wake, David; Wang, Yuting; Weaver, Benjamin Alan; Weijmans, Anne-Marie; Weinberg, David H.; Westfall, Kyle B.; Whelan, David G.; Wilcots, Eric; Wild, Vivienne; Williams, Rob A.; Wilson, John; Wood-Vasey, W. M.; Wylezalek, Dominika; Xiao, Ting; Yan, Renbin; Yang, Meng; Ybarra, Jason E.; Yèche, Christophe; Zakamska, Nadia; Zamora, Olga; Zarrouk, Pauline; Zasowski, Gail; Zhang, Kai; Zhao, Cheng; Zhao, Gong-Bo; Zheng, Zheng; Zheng, Zheng; Zhou, Zhi-Min; Zhu, Guangtun; Zinn, Joel C.; Zou, Hu Bibcode: 2018ApJS..235...42A Altcode: 2017arXiv170709322A The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since 2014 July. This paper describes the second data release from this phase, and the 14th from SDSS overall (making this Data Release Fourteen or DR14). This release makes the data taken by SDSS-IV in its first two years of operation (2014-2016 July) public. Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey; the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data-driven machine-learning algorithm known as “The Cannon” and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from the SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS web site (www.sdss.org) has been updated for this release and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020 and will be followed by SDSS-V. Title: VizieR Online Data Catalog: MUSCLES Treasury Survey. IV. M dwarf UV fluxes (Youngblood+, 2017) Authors: Youngblood, A.; France, K.; Loyd, R. O. P.; Brown, A.; Mason, J. P.; Schneider, P. C.; Tilley, M. A.; Berta-Thompson, Z. K.; Buccino, A.; Froning, C. S.; Hawley, S. L.; Linsky, J.; Mauas, P. J. D.; Redfield, S.; Kowalski, A.; Miguel, Y.; Newton, E. R.; Rugheimer, S.; Segura, A.; Roberge, A.; Vieytes, M. Bibcode: 2018yCat..18430031Y Altcode: We selected stars with HST UV spectra and ground-based optical spectra either obtained directly by us or available in the VLT/XSHOOTER or Keck/HIRES public archives.

Several targets have spectroscopic data obtained with the Dual Imaging Spectrograph (DIS) on the ARC 3.5m telescope at Apache Point Observatory (APO), R~2500, or the REOSC echelle spectrograph on the 2.15m telescope at Complejo Astronomico El Leoncito (CASLEO), R~12000, within a day or two of the HST observations. We also gathered spectra of GJ1132, GJ1214, and Proxima Cen on the nights of 2016 March 7-9 using the MIKE echelle spectrograph on the Magellan Clay telescope.

(2 data files). Title: Large Starspot Groups on HAT-P-11 in Activity Cycle 1 Authors: Morris, Brett M.; Hawley, Suzanne L.; Hebb, Leslie Bibcode: 2018RNAAS...2...26M Altcode: 2018RNAAS...2a..26M; 2018arXiv180110076M HAT-P-11 is a planet-hosting K4V star in the Kepler field, with an activity cycle that bear similarities to the Sun's. The chromospheric activity of HAT-P-11 indicates that a new activity cycle is beginning. We report ground-based observations with holographic diffuser photometry to measure the starspots of HAT-P-11 in its second observed magnetic activity cycle (Cycle 1). We find the area coverage of starspots within the transit chord for UTC 2017-10-30 is 14% --- which makes this transit the most spotted HAT-P-11 transit observed to date. We suggest that we are likely observing occultations of large spot groups appearing at the beginning of Cycle 1. Title: Photometric Analysis and Transit Times of TRAPPIST-1 B and C Authors: Morris, Brett M.; Agol, Eric; Hawley, Suzanne L. Bibcode: 2018RNAAS...2...10M Altcode: 2018RNAAS...2a..10M; 2018arXiv180104460M TRAPPIST-1 hosts seven Earth-sized planets transiting an M8 star. We observed mid-transit times of each of the inner two planets with the Astrophysical Research Consortium (ARC) 3.5 m Telescope at Apache Point Observatory (APO) to help constrain the planet masses with transit timing variations, and we outline a procedure for analyzing transit observations of late-M stars with APO. The transit times of TRAPPIST-1 b and c are $\mathrm{BJD}_{\mathrm{TDB}} = 2457580.87634^{+0.00034}_{-0.00034}$ and $2457558.89477^{+0.00080}_{-0.00085}$, respectively, which will help constrain the planet masses. Title: The Time-domain Spectroscopic Survey: Target Selection for Repeat Spectroscopy Authors: MacLeod, Chelsea L.; Green, Paul J.; Anderson, Scott F.; Eracleous, Michael; Ruan, John J.; Runnoe, Jessie; Brandt, William Nielsen; Badenes, Carles; Greene, Jenny; Morganson, Eric; Schmidt, Sarah J.; Schwope, Axel; Shen, Yue; Amaro, Rachael; Lebleu, Amy; Filiz Ak, Nurten; Grier, Catherine J.; Hoover, Daniel; McGraw, Sean M.; Dawson, Kyle; Hall, Patrick B.; Hawley, Suzanne L.; Mariappan, Vivek; Myers, Adam D.; Pâris, Isabelle; Schneider, Donald P.; Stassun, Keivan G.; Bershady, Matthew A.; Blanton, Michael R.; Seo, Hee-Jong; Tinker, Jeremy; Fernández-Trincado, J. G.; Chambers, Kenneth; Kaiser, Nick; Kudritzki, R. -P.; Magnier, Eugene; Metcalfe, Nigel; Waters, Chris Z. Bibcode: 2018AJ....155....6M Altcode: 2017arXiv170604240M As astronomers increasingly exploit the information available in the time domain, spectroscopic variability in particular opens broad new channels of investigation. Here we describe the selection algorithms for all targets intended for repeat spectroscopy in the Time Domain Spectroscopic Survey (TDSS), part of the extended Baryon Oscillation Spectroscopic Survey within the Sloan Digital Sky Survey (SDSS)-IV. Also discussed are the scientific rationale and technical constraints leading to these target selections. The TDSS includes a large “repeat quasar spectroscopy” (RQS) program delivering ∼13,000 repeat spectra of confirmed SDSS quasars, and several smaller “few-epoch spectroscopy” (FES) programs targeting specific classes of quasars as well as stars. The RQS program aims to provide a large and diverse quasar data set for studying variations in quasar spectra on timescales of years, a comparison sample for the FES quasar programs, and an opportunity for discovering rare, serendipitous events. The FES programs cover a wide variety of phenomena in both quasars and stars. Quasar FES programs target broad absorption line quasars, high signal-to-noise ratio normal broad line quasars, quasars with double-peaked or very asymmetric broad emission line profiles, binary supermassive black hole candidates, and the most photometrically variable quasars. Strongly variable stars are also targeted for repeat spectroscopy, encompassing many types of eclipsing binary systems, and classical pulsators like RR Lyrae. Other stellar FES programs allow spectroscopic variability studies of active ultracool dwarf stars, dwarf carbon stars, and white dwarf/M dwarf spectroscopic binaries. We present example TDSS spectra and describe anticipated sample sizes and results. Title: FBEYE: Analyzing Kepler light curves and validating flares Authors: Johnson, Emily; Davenport, James R. A.; Hawley, Suzanne L. Bibcode: 2017ascl.soft12011J Altcode: FBEYE, the "Flares By-Eye" detection suite, is written in IDL and analyzes Kepler light curves and validates flares. It works on any 3-column light curve that contains time, flux, and error. The success of flare identification is highly dependent on the smoothing routine, which may not be suitable for all sources. Title: Tidal Synchronization and Differential Rotation of Kepler Eclipsing Binaries Authors: Lurie, John C.; Vyhmeister, Karl; Hawley, Suzanne L.; Adilia, Jamel; Chen, Andrea; Davenport, James R. A.; Jurić, Mario; Puig-Holzman, Michael; Weisenburger, Kolby L. Bibcode: 2017AJ....154..250L Altcode: 2017arXiv171007339L Few observational constraints exist for the tidal synchronization rate of late-type stars, despite its fundamental role in binary evolution. We visually inspected the light curves of 2278 eclipsing binaries (EBs) from the Kepler Eclipsing Binary Catalog to identify those with starspot modulations, as well as other types of out-of-eclipse variability. We report rotation periods for 816 EBs with starspot modulations, and find that 79% of EBs with orbital periods of less than 10 days are synchronized. However, a population of short-period EBs exists, with rotation periods typically 13% slower than synchronous, which we attribute to the differential rotation of high-latitude starspots. At 10 days, there is a transition from predominantly circular, synchronized EBs to predominantly eccentric, pseudosynchronized EBs. This transition period is in good agreement with the predicted and observed circularization period for Milky Way field binaries. At orbital periods greater than about 30 days, the amount of tidal synchronization decreases. We also report 12 previously unidentified candidate δ Scuti and γ Doradus pulsators, as well as a candidate RS CVn system with an evolved primary that exhibits starspot occultations. For short-period contact binaries, we observe a period-color relation and compare it to previous studies. As a whole, these results represent the largest homogeneous study of tidal synchronization of late-type stars. Title: The 13th Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-IV Survey Mapping Nearby Galaxies at Apache Point Observatory Authors: Albareti, Franco D.; Allende Prieto, Carlos; Almeida, Andres; Anders, Friedrich; Anderson, Scott; Andrews, Brett H.; Aragón-Salamanca, Alfonso; Argudo-Fernández, Maria; Armengaud, Eric; Aubourg, Eric; Avila-Reese, Vladimir; Badenes, Carles; Bailey, Stephen; Barbuy, Beatriz; Barger, Kat; Barrera-Ballesteros, Jorge; Bartosz, Curtis; Basu, Sarbani; Bates, Dominic; Battaglia, Giuseppina; Baumgarten, Falk; Baur, Julien; Bautista, Julian; Beers, Timothy C.; Belfiore, Francesco; Bershady, Matthew; Bertran de Lis, Sara; Bird, Jonathan C.; Bizyaev, Dmitry; Blanc, Guillermo A.; Blanton, Michael; Blomqvist, Michael; Bolton, Adam S.; Borissova, J.; Bovy, Jo; Brandt, William Nielsen; Brinkmann, Jonathan; Brownstein, Joel R.; Bundy, Kevin; Burtin, Etienne; Busca, Nicolás G.; Camacho Chavez, Hugo Orlando; Cano Díaz, M.; Cappellari, Michele; Carrera, Ricardo; Chen, Yanping; Cherinka, Brian; Cheung, Edmond; Chiappini, Cristina; Chojnowski, Drew; Chuang, Chia-Hsun; Chung, Haeun; Cirolini, Rafael Fernando; Clerc, Nicolas; Cohen, Roger E.; Comerford, Julia M.; Comparat, Johan; Correa do Nascimento, Janaina; Cousinou, Marie-Claude; Covey, Kevin; Crane, Jeffrey D.; Croft, Rupert; Cunha, Katia; Darling, Jeremy; Davidson, James W., Jr.; Dawson, Kyle; Da Costa, Luiz; Da Silva Ilha, Gabriele; Deconto Machado, Alice; Delubac, Timothée; De Lee, Nathan; De la Macorra, Axel; De la Torre, Sylvain; Diamond-Stanic, Aleksandar M.; Donor, John; Downes, Juan Jose; Drory, Niv; Du, Cheng; Du Mas des Bourboux, Hélion; Dwelly, Tom; Ebelke, Garrett; Eigenbrot, Arthur; Eisenstein, Daniel J.; Elsworth, Yvonne P.; Emsellem, Eric; Eracleous, Michael; Escoffier, Stephanie; Evans, Michael L.; Falcón-Barroso, Jesús; Fan, Xiaohui; Favole, Ginevra; Fernandez-Alvar, Emma; Fernandez-Trincado, J. G.; Feuillet, Diane; Fleming, Scott W.; Font-Ribera, Andreu; Freischlad, Gordon; Frinchaboy, Peter; Fu, Hai; Gao, Yang; Garcia, Rafael A.; Garcia-Dias, R.; Garcia-Hernández, D. A.; Garcia Pérez, Ana E.; Gaulme, Patrick; Ge, Junqiang; Geisler, Douglas; Gillespie, Bruce; Gil Marin, Hector; Girardi, Léo; Goddard, Daniel; Gomez Maqueo Chew, Yilen; Gonzalez-Perez, Violeta; Grabowski, Kathleen; Green, Paul; Grier, Catherine J.; Grier, Thomas; Guo, Hong; Guy, Julien; Hagen, Alex; Hall, Matt; Harding, Paul; Harley, R. E.; Hasselquist, Sten; Hawley, Suzanne; Hayes, Christian R.; Hearty, Fred; Hekker, Saskia; Hernandez Toledo, Hector; Ho, Shirley; Hogg, David W.; Holley-Bockelmann, Kelly; Holtzman, Jon A.; Holzer, Parker H.; Hu, Jian; Huber, Daniel; Hutchinson, Timothy Alan; Hwang, Ho Seong; Ibarra-Medel, Héctor J.; Ivans, Inese I.; Ivory, KeShawn; Jaehnig, Kurt; Jensen, Trey W.; Johnson, Jennifer A.; Jones, Amy; Jullo, Eric; Kallinger, T.; Kinemuchi, Karen; Kirkby, David; Klaene, Mark; Kneib, Jean-Paul; Kollmeier, Juna A.; Lacerna, Ivan; Lane, Richard R.; Lang, Dustin; Laurent, Pierre; Law, David R.; Leauthaud, Alexie; Le Goff, Jean-Marc; Li, Chen; Li, Cheng; Li, Niu; Li, Ran; Liang, Fu-Heng; Liang, Yu; Lima, Marcos; Lin, Lihwai; Lin, Lin; Lin, Yen-Ting; Liu, Chao; Long, Dan; Lucatello, Sara; MacDonald, Nicholas; MacLeod, Chelsea L.; Mackereth, J. Ted; Mahadevan, Suvrath; Maia, Marcio Antonio Geimba; Maiolino, Roberto; Majewski, Steven R.; Malanushenko, Olena; Malanushenko, Viktor; Mallmann, Nícolas Dullius; Manchado, Arturo; Maraston, Claudia; Marques-Chaves, Rui; Martinez Valpuesta, Inma; Masters, Karen L.; Mathur, Savita; McGreer, Ian D.; Merloni, Andrea; Merrifield, Michael R.; Mészáros, Szabolcs; Meza, Andres; Miglio, Andrea; Minchev, Ivan; Molaverdikhani, Karan; Montero-Dorta, Antonio D.; Mosser, Benoit; Muna, Demitri; Myers, Adam; Nair, Preethi; Nandra, Kirpal; Ness, Melissa; Newman, Jeffrey A.; Nichol, Robert C.; Nidever, David L.; Nitschelm, Christian; O'Connell, Julia; Oravetz, Audrey; Oravetz, Daniel J.; Pace, Zachary; Padilla, Nelson; Palanque-Delabrouille, Nathalie; Pan, Kaike; Parejko, John; Paris, Isabelle; Park, Changbom; Peacock, John A.; Peirani, Sebastien; Pellejero-Ibanez, Marcos; Penny, Samantha; Percival, Will J.; Percival, Jeffrey W.; Perez-Fournon, Ismael; Petitjean, Patrick; Pieri, Matthew; Pinsonneault, Marc H.; Pisani, Alice; Prada, Francisco; Prakash, Abhishek; Price-Jones, Natalie; Raddick, M. Jordan; Rahman, Mubdi; Raichoor, Anand; Barboza Rembold, Sandro; Reyna, A. M.; Rich, James; Richstein, Hannah; Ridl, Jethro; Riffel, Rogemar A.; Riffel, Rogério; Rix, Hans-Walter; Robin, Annie C.; Rockosi, Constance M.; Rodríguez-Torres, Sergio; Rodrigues, Thaíse S.; Roe, Natalie; Roman Lopes, A.; Román-Zúñiga, Carlos; Ross, Ashley J.; Rossi, Graziano; Ruan, John; Ruggeri, Rossana; Runnoe, Jessie C.; Salazar-Albornoz, Salvador; Salvato, Mara; Sanchez, Sebastian F.; Sanchez, Ariel G.; Sanchez-Gallego, José R.; Santiago, Basílio Xavier; Schiavon, Ricardo; Schimoia, Jaderson S.; Schlafly, Eddie; Schlegel, David J.; Schneider, Donald P.; Schönrich, Ralph; Schultheis, Mathias; Schwope, Axel; Seo, Hee-Jong; Serenelli, Aldo; Sesar, Branimir; Shao, Zhengyi; Shetrone, Matthew; Shull, Michael; Silva Aguirre, Victor; Skrutskie, M. F.; Slosar, Anže; Smith, Michael; Smith, Verne V.; Sobeck, Jennifer; Somers, Garrett; Souto, Diogo; Stark, David V.; Stassun, Keivan G.; Steinmetz, Matthias; Stello, Dennis; Storchi Bergmann, Thaisa; Strauss, Michael A.; Streblyanska, Alina; Stringfellow, Guy S.; Suarez, Genaro; Sun, Jing; Taghizadeh-Popp, Manuchehr; Tang, Baitian; Tao, Charling; Tayar, Jamie; Tembe, Mita; Thomas, Daniel; Tinker, Jeremy; Tojeiro, Rita; Tremonti, Christy; Troup, Nicholas; Trump, Jonathan R.; Unda-Sanzana, Eduardo; Valenzuela, O.; Van den Bosch, Remco; Vargas-Magaña, Mariana; Vazquez, Jose Alberto; Villanova, Sandro; Vivek, M.; Vogt, Nicole; Wake, David; Walterbos, Rene; Wang, Yuting; Wang, Enci; Weaver, Benjamin Alan; Weijmans, Anne-Marie; Weinberg, David H.; Westfall, Kyle B.; Whelan, David G.; Wilcots, Eric; Wild, Vivienne; Williams, Rob A.; Wilson, John; Wood-Vasey, W. M.; Wylezalek, Dominika; Xiao, Ting; Yan, Renbin; Yang, Meng; Ybarra, Jason E.; Yeche, Christophe; Yuan, Fang-Ting; Zakamska, Nadia; Zamora, Olga; Zasowski, Gail; Zhang, Kai; Zhao, Cheng; Zhao, Gong-Bo; Zheng, Zheng; Zheng, Zheng; Zhou, Zhi-Min; Zhu, Guangtun; Zinn, Joel C.; Zou, Hu Bibcode: 2017ApJS..233...25A Altcode: 2016arXiv160802013S The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) began observations in 2014 July. It pursues three core programs: the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2), Mapping Nearby Galaxies at APO (MaNGA), and the Extended Baryon Oscillation Spectroscopic Survey (eBOSS). As well as its core program, eBOSS contains two major subprograms: the Time Domain Spectroscopic Survey (TDSS) and the SPectroscopic IDentification of ERosita Sources (SPIDERS). This paper describes the first data release from SDSS-IV, Data Release 13 (DR13). DR13 makes publicly available the first 1390 spatially resolved integral field unit observations of nearby galaxies from MaNGA. It includes new observations from eBOSS, completing the Sloan Extended QUasar, Emission-line galaxy, Luminous red galaxy Survey (SEQUELS), which also targeted variability-selected objects and X-ray-selected objects. DR13 includes new reductions of the SDSS-III BOSS data, improving the spectrophotometric calibration and redshift classification, and new reductions of the SDSS-III APOGEE-1 data, improving stellar parameters for dwarf stars and cooler stars. DR13 provides more robust and precise photometric calibrations. Value-added target catalogs relevant for eBOSS, TDSS, and SPIDERS and an updated red-clump catalog for APOGEE are also available. This paper describes the location and format of the data and provides references to important technical papers. The SDSS web site, http://www.sdss.org, provides links to the data, tutorials, examples of data access, and extensive documentation of the reduction and analysis procedures. DR13 is the first of a scheduled set that will contain new data and analyses from the planned ∼6 yr operations of SDSS-IV. Title: The Recurrent Nova Candidate M31N 1966-08a = 1968-10c is a Galactic Flare Star Authors: Shafter, A. W.; Henze, M.; Darnley, M. J.; Ciardullo, R.; Davis, B. D.; Hawley, S. L. Bibcode: 2017RNAAS...1...44S Altcode: 2017arXiv171205023S; 2017RNAAS...1a..44S A spectrum of the quiescent counterpart of the Recurrent Nova candidate M31N 1966-08a (= M31N 1968-10c) obtained with LRS2 on the Hobby-Eberly Telescope reveals the object to be a foreground Galactic dMe flare star, and not a nova in M31. Title: Modeling Repeated M-dwarf Flaring at an Earth-like Planet in the Habitable Zone: I. Atmospheric Effects for an Unmagnetized Planet Authors: Tilley, Matt A.; Segura, Antigona; Meadows, Victoria S.; Hawley, Suzanne; Davenport, James Bibcode: 2017arXiv171108484T Altcode: Understanding the impact of active M-dwarf stars on the atmospheric equilibrium and surface conditions of a habitable zone Earth-like planet is key to assessing M dwarf planet habitability. Previous modeling of the impact of electromagnetic (EM) radiation and protons from a single large flare on an Earth-like atmosphere indicated that significant and long-term reductions in ozone were possible, but the atmosphere recovered. These stars more realistically exhibit frequent flaring with a power-law distribution of energies. Here we use a coupled 1D photochemical and radiative-convective model to investigate the effects of repeated flaring on the photochemistry and surface UV of an Earth-like planet unprotected by an intrinsic magnetic field. We use time-resolved flare spectra obtained for the dM3 star AD Leo, combined with flare occurrence frequencies and total energies (typically 10$^{30.5}$ to 10$^{34}$ erg) from the 4-year Kepler light curve for the dM4 flare star GJ1243. Our model results show repeated EM-only flares have little effect on the ozone column depth, but that multiple proton events can rapidly destroy the ozone column. Combining the realistic flare and proton event frequencies with nominal CME & SEP geometries, we find the ozone column for an Earth-like planet can be depleted by 94% in 10 years, with a downward trend that makes recovery unlikely and suggests further destruction. For more extreme stellar inputs O3 depletion allows a constant 0.1-1 W m$^{-2}$ of UV-C at the planet's surface, which is likely detrimental to organic complexity. Our results suggest that active M dwarf hosts may comprehensively destroy ozone shields and subject the surface of magnetically-unprotected Earth-like planets to long-term radiation that can damage complex organic structures. However, this does not preclude habitability, as a safe haven for life could still exist below an ocean surface. Title: Toward Space-like Photometric Precision from the Ground with Beam-shaping Diffusers Authors: Stefansson, Gudmundur; Mahadevan, Suvrath; Hebb, Leslie; Wisniewski, John; Huehnerhoff, Joseph; Morris, Brett; Halverson, Sam; Zhao, Ming; Wright, Jason; O'rourke, Joseph; Knutson, Heather; Hawley, Suzanne; Kanodia, Shubham; Li, Yiting; Hagen, Lea M. Z.; Liu, Leo J.; Beatty, Thomas; Bender, Chad; Robertson, Paul; Dembicky, Jack; Gray, Candace; Ketzeback, William; McMillan, Russet; Rudyk, Theodore Bibcode: 2017ApJ...848....9S Altcode: 2017arXiv171001790S We demonstrate a path to hitherto unachievable differential photometric precisions from the ground, both in the optical and near-infrared (NIR), using custom-fabricated beam-shaping diffusers produced using specialized nanofabrication techniques. Such diffusers mold the focal plane image of a star into a broad and stable top-hat shape, minimizing photometric errors due to non-uniform pixel response, atmospheric seeing effects, imperfect guiding, and telescope-induced variable aberrations seen in defocusing. This PSF reshaping significantly increases the achievable dynamic range of our observations, increasing our observing efficiency and thus better averages over scintillation. Diffusers work in both collimated and converging beams. We present diffuser-assisted optical observations demonstrating {62}-16+26 ppm precision in 30 minute bins on a nearby bright star 16 Cygni A (V = 5.95) using the ARC 3.5 m telescope—within a factor of ∼2 of Kepler's photometric precision on the same star. We also show a transit of WASP-85-Ab (V = 11.2) and TRES-3b (V = 12.4), where the residuals bin down to {180}-41+66 ppm in 30 minute bins for WASP-85-Ab—a factor of ∼4 of the precision achieved by the K2 mission on this target—and to 101 ppm for TRES-3b. In the NIR, where diffusers may provide even more significant improvements over the current state of the art, our preliminary tests demonstrated {137}-36+64 ppm precision for a K S = 10.8 star on the 200 inch Hale Telescope. These photometric precisions match or surpass the expected photometric precisions of TESS for the same magnitude range. This technology is inexpensive, scalable, easily adaptable, and can have an important and immediate impact on the observations of transits and secondary eclipses of exoplanets. Title: Chromospheric Activity of HAT-P-11: An Unusually Active Planet-hosting K Star Authors: Morris, Brett M.; Hawley, Suzanne L.; Hebb, Leslie; Sakari, Charli; Davenport, James. R. A.; Isaacson, Howard; Howard, Andrew W.; Montet, Benjamin T.; Agol, Eric Bibcode: 2017ApJ...848...58M Altcode: 2017arXiv170903913M Kepler photometry of the hot Neptune host star HAT-P-11 suggests that its spot latitude distribution is comparable to the Sun’s near solar maximum. We search for evidence of an activity cycle in the Ca II H & K chromospheric emission S-index with archival Keck/HIRES spectra and observations from the echelle spectrograph on the Astrophysical Research Consortium 3.5 m Telescope at Apache Point Observatory. The chromospheric emission of HAT-P-11 is consistent with an ≳ 10 year activity cycle, which plateaued near maximum during the Kepler mission. In the cycle that we observed, the star seemed to spend more time near active maximum than minimum. We compare the {log}{R}{HK}{\prime } normalized chromospheric emission index of HAT-P-11 with other stars. HAT-P-11 has unusually strong chromospheric emission compared to planet-hosting stars of similar effective temperature and rotation period, perhaps due to tides raised by its planet. Title: The Starspots of HAT-P-11: Evidence for a Solar-like Dynamo Authors: Morris, Brett M.; Hebb, Leslie; Davenport, James R. A.; Rohn, Graeme; Hawley, Suzanne L. Bibcode: 2017ApJ...846...99M Altcode: 2017arXiv170802583M We measure the starspot radii and latitude distribution on the K4 dwarf HAT-P-11 from Kepler short-cadence photometry. We take advantage of starspot occultations by HAT-P-11’s highly misaligned planet to compare the spot size and latitude distributions to those of sunspots. We find that HAT-P-11’s spots are distributed in latitude much like sunspots near the solar activity maximum, with a mean spot latitude of ≈16° ± 1°. The majority of HAT-P-11’s starspots have physical sizes that closely resemble the sizes of sunspots at solar maximum. We estimate the mean spotted area coverage on HAT-P-11 to be {3}-1+6 % , roughly two orders of magnitude greater than the typical solar spotted area. Title: First Detection of a Strong Magnetic Field on a Bursty Brown Dwarf: Puzzle Solved Authors: Berdyugina, S. V.; Harrington, D. M.; Kuzmychov, O.; Kuhn, J. R.; Hallinan, G.; Kowalski, A. F.; Hawley, S. L. Bibcode: 2017ApJ...847...61B Altcode: 2017arXiv170902861B We report the first direct detection of a strong, 5 kG magnetic field on the surface of an active brown dwarf. LSR J1835+3259 is an M8.5 dwarf exhibiting transient radio and optical emission bursts modulated by fast rotation. We have detected the surface magnetic field as circularly polarized signatures in the 819 nm sodium lines when an active emission region faced the Earth. Modeling Stokes profiles of these lines reveals the effective temperature of 2800 K and log gravity acceleration of 4.5. These parameters place LSR J1835+3259 on evolutionary tracks as a young brown dwarf with the mass of 55+/- 4{M}{{J}} and age of 22 ± 4 Myr. Its magnetic field is at least 5.1 kG and covers at least 11% of the visible hemisphere. The active region topology recovered using line profile inversions comprises hot plasma loops with a vertical stratification of optical and radio emission sources. These loops rotate with the dwarf in and out of view causing periodic emission bursts. The magnetic field is detected at the base of the loops. This is the first time that we can quantitatively associate brown dwarf non-thermal bursts with a strong, 5 kG surface magnetic field and solve the puzzle of their driving mechanism. This is also the coolest known dwarf with such a strong surface magnetic field. The young age of LSR J1835+3259 implies that it may still maintain a disk, which may facilitate bursts via magnetospheric accretion, like in higher-mass T Tau-type stars. Our results pave a path toward magnetic studies of brown dwarfs and hot Jupiters. Title: Science-Driven Optimization of the LSST Observing Strategy Authors: LSST Science Collaboration; Marshall, Phil; Anguita, Timo; Bianco, Federica B.; Bellm, Eric C.; Brandt, Niel; Clarkson, Will; Connolly, Andy; Gawiser, Eric; Ivezic, Zeljko; Jones, Lynne; Lochner, Michelle; Lund, Michael B.; Mahabal, Ashish; Nidever, David; Olsen, Knut; Ridgway, Stephen; Rhodes, Jason; Shemmer, Ohad; Trilling, David; Vivas, Kathy; Walkowicz, Lucianne; Willman, Beth; Yoachim, Peter; Anderson, Scott; Antilogus, Pierre; Angus, Ruth; Arcavi, Iair; Awan, Humna; Biswas, Rahul; Bell, Keaton J.; Bennett, David; Britt, Chris; Buzasi, Derek; Casetti-Dinescu, Dana I.; Chomiuk, Laura; Claver, Chuck; Cook, Kem; Davenport, James; Debattista, Victor; Digel, Seth; Doctor, Zoheyr; Firth, R. E.; Foley, Ryan; Fong, Wen-fai; Galbany, Lluis; Giampapa, Mark; Gizis, John E.; Graham, Melissa L.; Grillmair, Carl; Gris, Phillipe; Haiman, Zoltan; Hartigan, Patrick; Hawley, Suzanne; Hlozek, Renee; Jha, Saurabh W.; Johns-Krull, C.; Kanbur, Shashi; Kalogera, Vassiliki; Kashyap, Vinay; Kasliwal, Vishal; Kessler, Richard; Kim, Alex; Kurczynski, Peter; Lahav, Ofer; Liu, Michael C.; Malz, Alex; Margutti, Raffaella; Matheson, Tom; McEwen, Jason D.; McGehee, Peregrine; Meibom, Soren; Meyers, Josh; Monet, Dave; Neilsen, Eric; Newman, Jeffrey; O'Dowd, Matt; Peiris, Hiranya V.; Penny, Matthew T.; Peters, Christina; Poleski, Radoslaw; Ponder, Kara; Richards, Gordon; Rho, Jeonghee; Rubin, David; Schmidt, Samuel; Schuhmann, Robert L.; Shporer, Avi; Slater, Colin; Smith, Nathan; Soares-Santos, Marcelles; Stassun, Keivan; Strader, Jay; Strauss, Michael; Street, Rachel; Stubbs, Christopher; Sullivan, Mark; Szkody, Paula; Trimble, Virginia; Tyson, Tony; de Val-Borro, Miguel; Valenti, Stefano; Wagoner, Robert; Wood-Vasey, W. Michael; Zauderer, Bevin Ashley Bibcode: 2017arXiv170804058L Altcode: The Large Synoptic Survey Telescope is designed to provide an unprecedented optical imaging dataset that will support investigations of our Solar System, Galaxy and Universe, across half the sky and over ten years of repeated observation. However, exactly how the LSST observations will be taken (the observing strategy or "cadence") is not yet finalized. In this dynamically-evolving community white paper, we explore how the detailed performance of the anticipated science investigations is expected to depend on small changes to the LSST observing strategy. Using realistic simulations of the LSST schedule and observation properties, we design and compute diagnostic metrics and Figures of Merit that provide quantitative evaluations of different observing strategies, analyzing their impact on a wide range of proposed science projects. This is work in progress: we are using this white paper to communicate to each other the relative merits of the observing strategy choices that could be made, in an effort to maximize the scientific value of the survey. The investigation of some science cases leads to suggestions for new strategies that could be simulated and potentially adopted. Notably, we find motivation for exploring departures from a spatially uniform annual tiling of the sky: focusing instead on different parts of the survey area in different years in a "rolling cadence" is likely to have significant benefits for a number of time domain and moving object astronomy projects. The communal assembly of a suite of quantified and homogeneously coded metrics is the vital first step towards an automated, systematic, science-based assessment of any given cadence simulation, that will enable the scheduling of the LSST to be as well-informed as possible. Title: The MUSCLES Treasury Survey. IV. Scaling Relations for Ultraviolet, Ca II K, and Energetic Particle Fluxes from M Dwarfs Authors: Youngblood, Allison; France, Kevin; Loyd, R. O. Parke; Brown, Alexander; Mason, James P.; Schneider, P. Christian; Tilley, Matt A.; Berta-Thompson, Zachory K.; Buccino, Andrea; Froning, Cynthia S.; Hawley, Suzanne L.; Linsky, Jeffrey; Mauas, Pablo J. D.; Redfield, Seth; Kowalski, Adam; Miguel, Yamila; Newton, Elisabeth R.; Rugheimer, Sarah; Segura, Antígona; Roberge, Aki; Vieytes, Mariela Bibcode: 2017ApJ...843...31Y Altcode: 2017arXiv170504361Y Characterizing the UV spectral energy distribution (SED) of an exoplanet host star is critically important for assessing its planet’s potential habitability, particularly for M dwarfs, as they are prime targets for current and near-term exoplanet characterization efforts and atmospheric models predict that their UV radiation can produce photochemistry on habitable zone planets different from that on Earth. To derive ground-based proxies for UV emission for use when Hubble Space Telescope (HST) observations are unavailable, we have assembled a sample of 15 early to mid-M dwarfs observed by HST and compared their nonsimultaneous UV and optical spectra. We find that the equivalent width of the chromospheric Ca II K line at 3933 Å, when corrected for spectral type, can be used to estimate the stellar surface flux in ultraviolet emission lines, including H I Lyα. In addition, we address another potential driver of habitability: energetic particle fluxes associated with flares. We present a new technique for estimating soft X-ray and >10 MeV proton flux during far-UV emission line flares (Si IV and He II) by assuming solar-like energy partitions. We analyze several flares from the M4 dwarf GJ 876 observed with HST and Chandra as part of the MUSCLES Treasury Survey and find that habitable zone planets orbiting GJ 876 are impacted by large Carrington-like flares with peak soft X-ray fluxes ≥10-3 W m-2 and possible proton fluxes ∼102-103 pfu, approximately four orders of magnitude more frequently than modern-day Earth. Title: Sloan Digital Sky Survey IV: Mapping the Milky Way, Nearby Galaxies, and the Distant Universe Authors: Blanton, Michael R.; Bershady, Matthew A.; Abolfathi, Bela; Albareti, Franco D.; Allende Prieto, Carlos; Almeida, Andres; Alonso-García, Javier; Anders, Friedrich; Anderson, Scott F.; Andrews, Brett; Aquino-Ortíz, Erik; Aragón-Salamanca, Alfonso; Argudo-Fernández, Maria; Armengaud, Eric; Aubourg, Eric; Avila-Reese, Vladimir; Badenes, Carles; Bailey, Stephen; Barger, Kathleen A.; Barrera-Ballesteros, Jorge; Bartosz, Curtis; Bates, Dominic; Baumgarten, Falk; Bautista, Julian; Beaton, Rachael; Beers, Timothy C.; Belfiore, Francesco; Bender, Chad F.; Berlind, Andreas A.; Bernardi, Mariangela; Beutler, Florian; Bird, Jonathan C.; Bizyaev, Dmitry; Blanc, Guillermo A.; Blomqvist, Michael; Bolton, Adam S.; Boquien, Médéric; Borissova, Jura; van den Bosch, Remco; Bovy, Jo; Brandt, William N.; Brinkmann, Jonathan; Brownstein, Joel R.; Bundy, Kevin; Burgasser, Adam J.; Burtin, Etienne; Busca, Nicolás G.; Cappellari, Michele; Delgado Carigi, Maria Leticia; Carlberg, Joleen K.; Carnero Rosell, Aurelio; Carrera, Ricardo; Chanover, Nancy J.; Cherinka, Brian; Cheung, Edmond; Gómez Maqueo Chew, Yilen; Chiappini, Cristina; Choi, Peter Doohyun; Chojnowski, Drew; Chuang, Chia-Hsun; Chung, Haeun; Cirolini, Rafael Fernando; Clerc, Nicolas; Cohen, Roger E.; Comparat, Johan; da Costa, Luiz; Cousinou, Marie-Claude; Covey, Kevin; Crane, Jeffrey D.; Croft, Rupert A. C.; Cruz-Gonzalez, Irene; Garrido Cuadra, Daniel; Cunha, Katia; Damke, Guillermo J.; Darling, Jeremy; Davies, Roger; Dawson, Kyle; de la Macorra, Axel; Dell'Agli, Flavia; De Lee, Nathan; Delubac, Timothée; Di Mille, Francesco; Diamond-Stanic, Aleks; Cano-Díaz, Mariana; Donor, John; Downes, Juan José; Drory, Niv; du Mas des Bourboux, Hélion; Duckworth, Christopher J.; Dwelly, Tom; Dyer, Jamie; Ebelke, Garrett; Eigenbrot, Arthur D.; Eisenstein, Daniel J.; Emsellem, Eric; Eracleous, Mike; Escoffier, Stephanie; Evans, Michael L.; Fan, Xiaohui; Fernández-Alvar, Emma; Fernandez-Trincado, J. G.; Feuillet, Diane K.; Finoguenov, Alexis; Fleming, Scott W.; Font-Ribera, Andreu; Fredrickson, Alexander; Freischlad, Gordon; Frinchaboy, Peter M.; Fuentes, Carla E.; Galbany, Lluís; Garcia-Dias, R.; García-Hernández, D. A.; Gaulme, Patrick; Geisler, Doug; Gelfand, Joseph D.; Gil-Marín, Héctor; Gillespie, Bruce A.; Goddard, Daniel; Gonzalez-Perez, Violeta; Grabowski, Kathleen; Green, Paul J.; Grier, Catherine J.; Gunn, James E.; Guo, Hong; Guy, Julien; Hagen, Alex; Hahn, ChangHoon; Hall, Matthew; Harding, Paul; Hasselquist, Sten; Hawley, Suzanne L.; Hearty, Fred; Gonzalez Hernández, Jonay I.; Ho, Shirley; Hogg, David W.; Holley-Bockelmann, Kelly; Holtzman, Jon A.; Holzer, Parker H.; Huehnerhoff, Joseph; Hutchinson, Timothy A.; Hwang, Ho Seong; Ibarra-Medel, Héctor J.; da Silva Ilha, Gabriele; Ivans, Inese I.; Ivory, KeShawn; Jackson, Kelly; Jensen, Trey W.; Johnson, Jennifer A.; Jones, Amy; Jönsson, Henrik; Jullo, Eric; Kamble, Vikrant; Kinemuchi, Karen; Kirkby, David; Kitaura, Francisco-Shu; Klaene, Mark; Knapp, Gillian R.; Kneib, Jean-Paul; Kollmeier, Juna A.; Lacerna, Ivan; Lane, Richard R.; Lang, Dustin; Law, David R.; Lazarz, Daniel; Lee, Youngbae; Le Goff, Jean-Marc; Liang, Fu-Heng; Li, Cheng; Li, Hongyu; Lian, Jianhui; Lima, Marcos; Lin, Lihwai; Lin, Yen-Ting; Bertran de Lis, Sara; Liu, Chao; de Icaza Lizaola, Miguel Angel C.; Long, Dan; Lucatello, Sara; Lundgren, Britt; MacDonald, Nicholas K.; Deconto Machado, Alice; MacLeod, Chelsea L.; Mahadevan, Suvrath; Geimba Maia, Marcio Antonio; Maiolino, Roberto; Majewski, Steven R.; Malanushenko, Elena; Malanushenko, Viktor; Manchado, Arturo; Mao, Shude; Maraston, Claudia; Marques-Chaves, Rui; Masseron, Thomas; Masters, Karen L.; McBride, Cameron K.; McDermid, Richard M.; McGrath, Brianne; McGreer, Ian D.; Medina Peña, Nicolás; Melendez, Matthew; Merloni, Andrea; Merrifield, Michael R.; Meszaros, Szabolcs; Meza, Andres; Minchev, Ivan; Minniti, Dante; Miyaji, Takamitsu; More, Surhud; Mulchaey, John; Müller-Sánchez, Francisco; Muna, Demitri; Munoz, Ricardo R.; Myers, Adam D.; Nair, Preethi; Nandra, Kirpal; Correa do Nascimento, Janaina; Negrete, Alenka; Ness, Melissa; Newman, Jeffrey A.; Nichol, Robert C.; Nidever, David L.; Nitschelm, Christian; Ntelis, Pierros; O'Connell, Julia E.; Oelkers, Ryan J.; Oravetz, Audrey; Oravetz, Daniel; Pace, Zach; Padilla, Nelson; Palanque-Delabrouille, Nathalie; Alonso Palicio, Pedro; Pan, Kaike; Parejko, John K.; Parikh, Taniya; Pâris, Isabelle; Park, Changbom; Patten, Alim Y.; Peirani, Sebastien; Pellejero-Ibanez, Marcos; Penny, Samantha; Percival, Will J.; Perez-Fournon, Ismael; Petitjean, Patrick; Pieri, Matthew M.; Pinsonneault, Marc; Pisani, Alice; Poleski, Radosław; Prada, Francisco; Prakash, Abhishek; Queiroz, Anna Bárbara de Andrade; Raddick, M. Jordan; Raichoor, Anand; Barboza Rembold, Sandro; Richstein, Hannah; Riffel, Rogemar A.; Riffel, Rogério; Rix, Hans-Walter; Robin, Annie C.; Rockosi, Constance M.; Rodríguez-Torres, Sergio; Roman-Lopes, A.; Román-Zúñiga, Carlos; Rosado, Margarita; Ross, Ashley J.; Rossi, Graziano; Ruan, John; Ruggeri, Rossana; Rykoff, Eli S.; Salazar-Albornoz, Salvador; Salvato, Mara; Sánchez, Ariel G.; Aguado, D. S.; Sánchez-Gallego, José R.; Santana, Felipe A.; Santiago, Basílio Xavier; Sayres, Conor; Schiavon, Ricardo P.; da Silva Schimoia, Jaderson; Schlafly, Edward F.; Schlegel, David J.; Schneider, Donald P.; Schultheis, Mathias; Schuster, William J.; Schwope, Axel; Seo, Hee-Jong; Shao, Zhengyi; Shen, Shiyin; Shetrone, Matthew; Shull, Michael; Simon, Joshua D.; Skinner, Danielle; Skrutskie, M. F.; Slosar, Anže; Smith, Verne V.; Sobeck, Jennifer S.; Sobreira, Flavia; Somers, Garrett; Souto, Diogo; Stark, David V.; Stassun, Keivan; Stauffer, Fritz; Steinmetz, Matthias; Storchi-Bergmann, Thaisa; Streblyanska, Alina; Stringfellow, Guy S.; Suárez, Genaro; Sun, Jing; Suzuki, Nao; Szigeti, Laszlo; Taghizadeh-Popp, Manuchehr; Tang, Baitian; Tao, Charling; Tayar, Jamie; Tembe, Mita; Teske, Johanna; Thakar, Aniruddha R.; Thomas, Daniel; Thompson, Benjamin A.; Tinker, Jeremy L.; Tissera, Patricia; Tojeiro, Rita; Hernandez Toledo, Hector; de la Torre, Sylvain; Tremonti, Christy; Troup, Nicholas W.; Valenzuela, Octavio; Martinez Valpuesta, Inma; Vargas-González, Jaime; Vargas-Magaña, Mariana; Vazquez, Jose Alberto; Villanova, Sandro; Vivek, M.; Vogt, Nicole; Wake, David; Walterbos, Rene; Wang, Yuting; Weaver, Benjamin Alan; Weijmans, Anne-Marie; Weinberg, David H.; Westfall, Kyle B.; Whelan, David G.; Wild, Vivienne; Wilson, John; Wood-Vasey, W. M.; Wylezalek, Dominika; Xiao, Ting; Yan, Renbin; Yang, Meng; Ybarra, Jason E.; Yèche, Christophe; Zakamska, Nadia; Zamora, Olga; Zarrouk, Pauline; Zasowski, Gail; Zhang, Kai; Zhao, Gong-Bo; Zheng, Zheng; Zheng, Zheng; Zhou, Xu; Zhou, Zhi-Min; Zhu, Guangtun B.; Zoccali, Manuela; Zou, Hu Bibcode: 2017AJ....154...28B Altcode: 2017arXiv170300052B We describe the Sloan Digital Sky Survey IV (SDSS-IV), a project encompassing three major spectroscopic programs. The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is observing hundreds of thousands of Milky Way stars at high resolution and high signal-to-noise ratios in the near-infrared. The Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey is obtaining spatially resolved spectroscopy for thousands of nearby galaxies (median z∼ 0.03). The extended Baryon Oscillation Spectroscopic Survey (eBOSS) is mapping the galaxy, quasar, and neutral gas distributions between z∼ 0.6 and 3.5 to constrain cosmology using baryon acoustic oscillations, redshift space distortions, and the shape of the power spectrum. Within eBOSS, we are conducting two major subprograms: the SPectroscopic IDentification of eROSITA Sources (SPIDERS), investigating X-ray AGNs and galaxies in X-ray clusters, and the Time Domain Spectroscopic Survey (TDSS), obtaining spectra of variable sources. All programs use the 2.5 m Sloan Foundation Telescope at the Apache Point Observatory; observations there began in Summer 2014. APOGEE-2 also operates a second near-infrared spectrograph at the 2.5 m du Pont Telescope at Las Campanas Observatory, with observations beginning in early 2017. Observations at both facilities are scheduled to continue through 2020. In keeping with previous SDSS policy, SDSS-IV provides regularly scheduled public data releases; the first one, Data Release 13, was made available in 2016 July. Title: Hydrogen Balmer Line Broadening in Solar and Stellar Flares Authors: Kowalski, Adam F.; Allred, Joel C.; Uitenbroek, Han; Tremblay, Pier-Emmanuel; Brown, Stephen; Carlsson, Mats; Osten, Rachel A.; Wisniewski, John P.; Hawley, Suzanne L. Bibcode: 2017ApJ...837..125K Altcode: 2017arXiv170203321K The broadening of the hydrogen lines during flares is thought to result from increased charge (electron, proton) density in the flare chromosphere. However, disagreements between theory and modeling prescriptions have precluded an accurate diagnostic of the degree of ionization and compression resulting from flare heating in the chromosphere. To resolve this issue, we have incorporated the unified theory of electric pressure broadening of the hydrogen lines into the non-LTE radiative-transfer code RH. This broadening prescription produces a much more realistic spectrum of the quiescent, A0 star Vega compared to the analytic approximations used as a damping parameter in the Voigt profiles. We test recent radiative-hydrodynamic (RHD) simulations of the atmospheric response to high nonthermal electron beam fluxes with the new broadening prescription and find that the Balmer lines are overbroadened at the densest times in the simulations. Adding many simultaneously heated and cooling model loops as a “multithread” model improves the agreement with the observations. We revisit the three-component phenomenological flare model of the YZ CMi Megaflare using recent and new RHD models. The evolution of the broadening, line flux ratios, and continuum flux ratios are well-reproduced by a multithread model with high-flux nonthermal electron beam heating, an extended decay phase model, and a “hot spot” atmosphere heated by an ultrarelativistic electron beam with reasonable filling factors: ∼0.1%, 1%, and 0.1% of the visible stellar hemisphere, respectively. The new modeling motivates future work to understand the origin of the extended gradual phase emission. Title: The Active Latitudes of HAT-P-11 Authors: Morris, Brett; Hebb, Leslie; Davenport, James R. A.; Hawley, Suzanne L. Bibcode: 2017AAS...22923005M Altcode: Transiting planets map the brightness of their host stars, as the flux lost during exoplanet transits is proportional to the integrated flux occulted by the planet. We analyze four years of Kepler short-cadence photometry of HAT-P-11 - an active K4 dwarf with a 29 day rotation period, orbited by a hot-Neptune. Due to its highly-misaligned orbit, the planet occults most stellar latitudes during each transit, and the latitude distribution of spots is encoded in the transit light curves. We model each spot occultation in transit to create a spot map of HAT-P-11, which reveals two active latitudes near ±17 degrees. We investigate whether the spot distribution changes in time, and we compare the spot latitude distributions of HAT-P-11 and the Sun throughout the solar activity cycle. Title: VizieR Online Data Catalog: SDSS WD-M binary parameters (Raymond+, 2003) Authors: Raymond, S. N.; Szkody, P.; Hawley, S. L.; Anderson, S. F.; Brinkmann, J.; Covey, K. R.; McGehee, P. M.; Schneider, D. P.; West, A. A.; York, D. G. Bibcode: 2016yCat..51252621R Altcode: We have compiled a sample of 109 WD-M binaries from the first year of the Sloan Digital Sky Survey.

(1 data file). Title: Kepler Flares. IV. A Comprehensive Analysis of the Activity of the dM4e Star GJ 1243 Authors: Silverberg, Steven M.; Kowalski, Adam F.; Davenport, James R. A.; Wisniewski, John P.; Hawley, Suzanne L.; Hilton, Eric J. Bibcode: 2016ApJ...829..129S Altcode: 2016arXiv160703886S We present a comprehensive study of the active dM4e star GJ 1243. We use previous observations and ground-based echelle spectroscopy to determine that GJ 1243 is a member of the Argus association of field stars, suggesting it is ∼ 30{--}50 {{Myr}} old. We analyze 11 months of 1 minute cadence data from Kepler, presenting Kepler flare frequency distributions, as well as determining correlations between flare energy, amplitude, duration, and decay time. We find that the exponent α of the power-law flare energy distribution varies in time, primarily due to completeness of sample and the low frequency of high-energy flares. We also find a deviation from a single power law at high energy. We use ground-based spectroscopic observations that were simultaneous with the Kepler data to provide simultaneous photometric and spectroscopic analysis of three low-energy flares, the lowest-energy dMe flares with detailed spectral analysis to date on any star. The spectroscopic data from these flares extend constraints for radiative hydrodynamic flare models to a lower energy regime than has previously been studied. We use this simultaneous spectroscopy and Kepler photometry to develop approximate conversions from the Kepler bandpass to the traditional U and B bands. This conversion will be a critical factor in comparing any Kepler flare analyses to the canon of previous ground-based flare studies. Title: Maximizing Science in the Era of LSST: A Community-Based Study of Needed US Capabilities Authors: Najita, Joan; Willman, Beth; Finkbeiner, Douglas P.; Foley, Ryan J.; Hawley, Suzanne; Newman, Jeffrey A.; Rudnick, Gregory; Simon, Joshua D.; Trilling, David; Street, Rachel; Bolton, Adam; Angus, Ruth; Bell, Eric F.; Buzasi, Derek; Ciardi, David; Davenport, James R. A.; Dawson, Will; Dickinson, Mark; Drlica-Wagner, Alex; Elias, Jay; Erb, Dawn; Feaga, Lori; Fong, Wen-fai; Gawiser, Eric; Giampapa, Mark; Guhathakurta, Puragra; Hoffman, Jennifer L.; Hsieh, Henry; Jennings, Elise; Johnston, Kathryn V.; Kashyap, Vinay; Li, Ting S.; Linder, Eric; Mandelbaum, Rachel; Marshall, Phil; Matheson, Thomas; Meibom, Soren; Miller, Bryan W.; O'Meara, John; Reddy, Vishnu; Ridgway, Steve; Rockosi, Constance M.; Sand, David J.; Schafer, Chad; Schmidt, Sam; Sesar, Branimir; Sheppard, Scott S.; Thomas, Cristina A.; Tollerud, Erik J.; Trump, Jon; von der Linden, Anja Bibcode: 2016arXiv161001661N Altcode: The Large Synoptic Survey Telescope (LSST) will be a discovery machine for the astronomy and physics communities, revealing astrophysical phenomena from the Solar System to the outer reaches of the observable Universe. While many discoveries will be made using LSST data alone, taking full scientific advantage of LSST will require ground-based optical-infrared (OIR) supporting capabilities, e.g., observing time on telescopes, instrumentation, computing resources, and other infrastructure. This community-based study identifies, from a science-driven perspective, capabilities that are needed to maximize LSST science. Expanding on the initial steps taken in the 2015 OIR System Report, the study takes a detailed, quantitative look at the capabilities needed to accomplish six representative LSST-enabled science programs that connect closely with scientific priorities from the 2010 decadal surveys. The study prioritizes the resources needed to accomplish the science programs and highlights ways that existing, planned, and future resources could be positioned to accomplish the science goals. Title: Astrophysical Research Consortium Telescope Imaging Camera (ARCTIC) facility optical imager for the Apache Point Observatory 3.5m telescope Authors: Huehnerhoff, Joseph; Ketzeback, William; Bradley, Alaina; Dembicky, Jack; Doughty, Caitlin; Hawley, Suzanne; Johnson, Courtney; Klaene, Mark; Leon, Ed; McMillan, Russet; Owen, Russell; Sayres, Conor; Sheen, Tyler; Shugart, Alysha Bibcode: 2016SPIE.9908E..5HH Altcode: The Astrophysical Research Consortium Telescope Imaging Camera, ARCTIC, is a new optical imaging camera now in use at the Astrophysical Research Consortium (ARC) 3.5m telescope at Apache Point Observatory (APO). As a facility instrument, the design criteria broadly encompassed many current and future science opportunities, and the components were built for quick repair or replacement, to minimize down-time. Examples include a quick change shutter, filter drive components accessible from the exterior and redundant amplifiers on the detector. The detector is a Semiconductor Technology Associates (STA) device with several key properties (e.g. high quantum efficiency, low read-noise, quick readout, minimal fringing, operational bandpass 350-950nm). Focal reducing optics (f/10.3 to f/8.0) were built to control aberrations over a 7.8'x7.8' field, with a plate scale of 0.11" per 0.15 micron pixel. The instrument body and dewar were designed to be simple and robust with only two components to the structure forward of the dewar, which in turn has minimal feedthroughs and permeation areas and holds a vacuum <10-8 Torr. A custom shutter was also designed, using pneumatics as the driving force. This device provides exceptional performance and reduces heat near the optical path. Measured performance is repeatable at the 2ms level and offers field uniformity to the same level of precision. The ARCTIC facility imager will provide excellent science capability with robust operation and minimal maintenance for the next decade or more at APO. Title: Flares In Time-Domain Surveys Authors: Kowalski, Adam; Hawley, Suzanne; Davenport, James; Berlicki, Arkadiusz; Cauzzi, Gianna; Fletcher, Lyndsay; Heinzel, Petr; Notsu, Yuta; Loyd, Parke; Martinez Oliveros, Juan Carlos; Pugh, Chloe; Schmidt, Sarah Jane; Karmakar, Subhajeet; Pye, John; Flaccomio, Ettore Bibcode: 2016csss.confE.126K Altcode: Proceedings for the splinter session "Flares in Time-Domain Surveys" convened at Cool Stars 19 on June 07, 2016 in Uppsala, Sweden. Contains a two page summary of the splinter session, links to YouTube talks, and a PDF copy of the slides from the presenters. Title: Maximizing Science in the Era of LSST, Stars Study Group Report: Rotation and Magnetic Activity in the Galactic Field Population and in Open Star Clusters Authors: Hawley, Suzanne L.; Angus, Ruth; Buzasi, Derek; Davenport, James R. A.; Giampapa, Mark; Kashyap, Vinay; Meibom, Soren Bibcode: 2016arXiv160704302H Altcode: This is the stars chapter of the Kavli workshop report, which resulted from the community-based study of needed US OIR capabilities in the LSST era. The full report, which will include this chapter, is anticipated to be available in Fall 2016. See NOAO website (http://www.noao.edu/meetings/lsst-oir-study/) for more details. Title: The MUSCLES Treasury Survey. I. Motivation and Overview Authors: France, Kevin; Loyd, R. O. Parke; Youngblood, Allison; Brown, Alexander; Schneider, P. Christian; Hawley, Suzanne L.; Froning, Cynthia S.; Linsky, Jeffrey L.; Roberge, Aki; Buccino, Andrea P.; Davenport, James R. A.; Fontenla, Juan M.; Kaltenegger, Lisa; Kowalski, Adam F.; Mauas, Pablo J. D.; Miguel, Yamila; Redfield, Seth; Rugheimer, Sarah; Tian, Feng; Vieytes, Mariela C.; Walkowicz, Lucianne M.; Weisenburger, Kolby L. Bibcode: 2016ApJ...820...89F Altcode: 2016arXiv160209142F Ground- and space-based planet searches employing radial velocity techniques and transit photometry have detected thousands of planet-hosting stars in the Milky Way. With so many planets discovered, the next step toward identifying potentially habitable planets is atmospheric characterization. While the Sun-Earth system provides a good framework for understanding the atmospheric chemistry of Earth-like planets around solar-type stars, the observational and theoretical constraints on the atmospheres of rocky planets in the habitable zones (HZs) around low-mass stars (K and M dwarfs) are relatively few. The chemistry of these atmospheres is controlled by the shape and absolute flux of the stellar spectral energy distribution (SED), however, flux distributions of relatively inactive low-mass stars are poorly understood at present. To address this issue, we have executed a panchromatic (X-ray to mid-IR) study of the SEDs of 11 nearby planet-hosting stars, the Measurements of the Ultraviolet Spectral Characteristics of Low-mass Exoplanetary Systems (MUSCLES) Treasury Survey. The MUSCLES program consists visible observations from Hubble and ground-based observatories. Infrared and astrophysically inaccessible wavelengths (EUV and Lyα) are reconstructed using stellar model spectra to fill in gaps in the observational data. In this overview and the companion papers describing the MUSCLES survey, we show that energetic radiation (X-ray and ultraviolet) is present from magnetically active stellar atmospheres at all times for stars as late as M6. The emission line luminosities of C IV and Mg II are strongly correlated with band-integrated luminosities and we present empirical relations that can be used to estimate broadband FUV and XUV (≡X-ray + EUV) fluxes from individual stellar emission line measurements. We find that while the slope of the SED, FUV/NUV, increases by approximately two orders of magnitude form early K to late M dwarfs (≈0.01-1), the absolute FUV and XUV flux levels at their corresponding HZ distances are constant to within factors of a few, spanning the range 10-70 erg cm-2 s-1 in the HZ. Despite the lack of strong stellar activity indicators in their optical spectra, several of the M dwarfs in our sample show spectacular UV flare emission in their light curves. We present an example with flare/quiescent ultraviolet flux ratios of the order of 100:1 where the transition region energy output during the flare is comparable to the total quiescent luminosity of the star Eflare(UV) ∼ 0.3 L*Δt (Δt = 1 s). Finally, we interpret enhanced L(line)/LBol ratios for C IV and N v as tentative observational evidence for the interaction of planets with large planetary mass-to-orbital distance ratios (Mplan/aplan) with the transition regions of their host stars.

Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS 5-26555. Title: M Dwarf Flare Continuum Variations on One-second Timescales: Calibrating and Modeling of ULTRACAM Flare Color Indices Authors: Kowalski, Adam F.; Mathioudakis, Mihalis; Hawley, Suzanne L.; Wisniewski, John P.; Dhillon, Vik S.; Marsh, Tom R.; Hilton, Eric J.; Brown, Benjamin P. Bibcode: 2016ApJ...820...95K Altcode: 2016arXiv160204879K We present a large data set of high-cadence dMe flare light curves obtained with custom continuum filters on the triple-beam, high-speed camera system ULTRACAM. The measurements provide constraints for models of the near-ultraviolet (NUV) and optical continuum spectral evolution on timescales of ≈1 s. We provide a robust interpretation of the flare emission in the ULTRACAM filters using simultaneously obtained low-resolution spectra during two moderate-sized flares in the dM4.5e star YZ CMi. By avoiding the spectral complexity within the broadband Johnson filters, the ULTRACAM filters are shown to characterize bona fide continuum emission in the NUV, blue, and red wavelength regimes. The NUV/blue flux ratio in flares is equivalent to a Balmer jump ratio, and the blue/red flux ratio provides an estimate for the color temperature of the optical continuum emission. We present a new “color-color” relationship for these continuum flux ratios at the peaks of the flares. Using the RADYN and RH codes, we interpret the ULTRACAM filter emission using the dominant emission processes from a radiative-hydrodynamic flare model with a high nonthermal electron beam flux, which explains a hot, T ≈ 104 K, color temperature at blue-to-red optical wavelengths and a small Balmer jump ratio as observed in moderate-sized and large flares alike. We also discuss the high time resolution, high signal-to-noise continuum color variations observed in YZ CMi during a giant flare, which increased the NUV flux from this star by over a factor of 100.

Based on observations obtained with the Apache Point Observatory 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium, based on observations made with the William Herschel Telescope operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofsica de Canarias, and observations, and based on observations made with the ESO Telescopes at the La Silla Paranal Observatory under programme ID 085.D-0501(A). Title: Synergy between solar and stellar flares: challenges and perspectives Authors: Hawley, Suzanne L. Bibcode: 2016IAUS..320..419H Altcode: I will review the current status of stellar flare observations and models, highlight similarities and differences with solar flares, and plead for additional data and insight from the ``Sun as a Star''. Title: Examining the ages of M7-L8 dwarfs with the BOSS Ultracool Dwarf sample Authors: Schmidt, Sarah J.; Hawley, Suzanne L.; West, Andrew A.; Bochanski, John J. Bibcode: 2016AAS...22712103S Altcode: We present the latest results from the BOSS Ultracool Dwarfs (BUD) sample of 12998 M7-L8 dwarfs, identified from a combination of photometry and spectroscopy from the Sloan Digital Sky Survey (SDSS). Using a cross-match of the BUD sample to the Two Micron All-Sky Survey (2MASS) and the Wide-field Infrared Survey Explorer (WISE) catalogs, we measure both colors and proper motions for the majority of the sample. The proper motions, combined with radial velocities from SDSS spectra and updated distance estimates based on i-Ks colors, yield three-dimensional velocities for 9121 ultracool dwarfs. We usethese velocities as statistical proxies for age to identify and test other potential age indicators, including H<span style="line-height:20.8px">α</span> emission, atomic line strengths, molecular band depths, and broad-band colors. Title: Solar and Stellar Flares and their Effects on Planets Authors: Kosovichev, A. G.; Hawley, S. L.; Heinzel, P. Bibcode: 2016IAUS..320.....K Altcode: No abstract at ADS Title: New Insights into White-Light Flare Emission from Radiative-Hydrodynamic Modeling of a Chromospheric Condensation Authors: Kowalski, Adam F.; Hawley, S. L.; Carlsson, M.; Allred, J. C.; Uitenbroek, H.; Osten, R. A.; Holman, G. Bibcode: 2015SoPh..290.3487K Altcode: 2015SoPh..tmp...61K; 2015arXiv150307057K The heating mechanism at high densities during M-dwarf flares is poorly understood. Spectra of M-dwarf flares in the optical and near-ultraviolet wavelength regimes have revealed three continuum components during the impulsive phase: 1) an energetically dominant blackbody component with a color temperature of T ≈104K in the blue-optical, 2) a smaller amount of Balmer continuum emission in the near-ultraviolet at λ ≤3 646 Å, and 3) an apparent pseudo-continuum of blended high-order Balmer lines between λ =3 646 Å and λ ≈3 900 Å. These properties are not reproduced by models that employ a typical "solar-type" flare heating level of ≤1011ergcm−2s−1 in nonthermal electrons, and therefore our understanding of these spectra is limited to a phenomenological three-component interpretation. We present a new 1D radiative-hydrodynamic model of an M-dwarf flare from precipitating nonthermal electrons with a high energy flux of 1013ergcm−2s−1. The simulation produces bright near-ultraviolet and optical continuum emission from a dense (n >1015cm−3), hot (T ≈12 000 -13 500 K) chromospheric condensation. For the first time, the observed color temperature and Balmer jump ratio are produced self-consistently in a radiative-hydrodynamic flare model. We find that a T ≈104K blackbody-like continuum component and a low Balmer jump ratio result from optically thick Balmer (∞ →n =2 ) and Paschen recombination (∞ →n =3 ) radiation, and thus the properties of the flux spectrum are caused by blue (λ ≈4 300 Å) light escaping over a larger physical depth range than by red (λ ≈6 700 Å) and near-ultraviolet (λ ≈3 500 Å) light. To model the near-ultraviolet pseudo-continuum previously attributed to overlapping Balmer lines, we include the extra Balmer continuum opacity from Landau-Zener transitions that result from merged, high-order energy levels of hydrogen in a dense, partially ionized atmosphere. This reveals a new diagnostic of ambient charge density in the densest regions of the atmosphere that are heated during dMe and solar flares. Title: Using Transiting Exoplanets to Study Starspots with Kepler Authors: Davenport, James R. A.; Hebb, Leslie; Hawley, Suzanne Bibcode: 2015IAUGA..2257832D Altcode: Starspots are a fundamental manifestation of stellar dynamos that constrain the surface magnetic field strength and topology. Kepler has already produced the first ensemble studies of starspots, discovering rotation periods and rough spot properties for thousands of stars across the main sequence. Here we study the G dwarf Kepler 17, which hosts a transiting 2.5 Jupiter mass exoplanet on a 1.5 day orbit. Starspots are frequently occulted during transit, allowing us to probe smaller-scale starspot regions on the stellar surface along the projected path of the planet. These planet-spot occultations reveal the presence of at least 7 unique starspot groups on the stellar surface at any time. The spot crossings also give an empirical estimate of the starspot temperature contrast, which we find are consistent with the Solar umbra. Using over 4 years of data for Kepler 17, we observe changes in the starspot positions and sizes indicative of differential rotation and active region diffusion. Using an MCMC-based light curve modeling code, we determine the positions and sizes of each spot group over time. Our approach is novel in modeling both the in- and out-of transit features in the light curve, allowing us to break fundamental degeneracies between spot size, latitude, and contrast. This technique constrains key properties for understanding stellar dynamos, including the stellar rotation period, differential rotation rate, and spot diffusion timescales. Title: Properties of Flares on GKM Stars in Kepler Authors: Hawley, Suzanne; Davenport, James R. A.; Hebb, Leslie; Kowalski, Adam Francis; Wisniewski, John Bibcode: 2015IAUGA..2253855H Altcode: We analyze Kepler observations of G and K stars and determine flare properties, frequencies and energies from both long and short cadence data. We compare these with our previous results for M dwarfs and investigate correlations with rotation, starspot phase, differential rotation and starspot evolution. Title: Synergy Between Solar and Stellar Flares: Challenges and Perspectives Authors: Hawley, Suzanne Bibcode: 2015IAUGA..2250517H Altcode: I will review the current status of stellar flare observations and models, highlight similarities and differences with solar flares, and plead for additional data and insight from the "Sun as a Star". Title: The search for star-planet interactions in eccentric systems Authors: Hodgson, John, II; Christian, Damian; Hawley, Suzanne Bibcode: 2015IAUGA..2256241H Altcode: We have undertaken a study to determine if the orbital geometry of exoplanets affects the activity of their host stars by observing a sample of planetary systems known to contain massive planets on short period, highly elliptical orbits. While recent studies in the optical, UV, and X-Ray have shown enhanced chromospheric activity for stars hosting exoplanets with orbital semi-major axes less than 0.1 AU [1, 2, 3, 4], it is not yet clear whether this activity is driven by magnetic or tidal interactions. In this study, we are probing the dependence of star-planet interactions (SPI) on orbital geometry in a selection of eccentric systems by analyzing the Ca II H & K emission lines for variability phased with the planet's orbit. We have obtained high resolution spectra of this systems with the ARCES on the APO 3.5m from the Keck Observatory Archive. We shall describe our methodology and review our results on how the orbital geometry of the planet affects the activity of its host star.References[1] Krejcova, T., & Budaj, J., 2012, A&A, 540, A82[2] Shkolnik, E., 2013, ApJ pre-print from arXiv:1301.6192v1[3] Kashyap, V.L., Drake, J.J., & Saar, S.H., 2008, ApJ, 687, 1339[4] Poppenhaeger, K., Robrade, J., & Schmitt, J.H., 2010, A&A, 515, A98 Title: The Eleventh and Twelfth Data Releases of the Sloan Digital Sky Survey: Final Data from SDSS-III Authors: Alam, Shadab; Albareti, Franco D.; Allende Prieto, Carlos; Anders, F.; Anderson, Scott F.; Anderton, Timothy; Andrews, Brett H.; Armengaud, Eric; Aubourg, Éric; Bailey, Stephen; Basu, Sarbani; Bautista, Julian E.; Beaton, Rachael L.; Beers, Timothy C.; Bender, Chad F.; Berlind, Andreas A.; Beutler, Florian; Bhardwaj, Vaishali; Bird, Jonathan C.; Bizyaev, Dmitry; Blake, Cullen H.; Blanton, Michael R.; Blomqvist, Michael; Bochanski, John J.; Bolton, Adam S.; Bovy, Jo; Shelden Bradley, A.; Brandt, W. N.; Brauer, D. E.; Brinkmann, J.; Brown, Peter J.; Brownstein, Joel R.; Burden, Angela; Burtin, Etienne; Busca, Nicolás G.; Cai, Zheng; Capozzi, Diego; Carnero Rosell, Aurelio; Carr, Michael A.; Carrera, Ricardo; Chambers, K. C.; Chaplin, William James; Chen, Yen-Chi; Chiappini, Cristina; Chojnowski, S. Drew; Chuang, Chia-Hsun; Clerc, Nicolas; Comparat, Johan; Covey, Kevin; Croft, Rupert A. C.; Cuesta, Antonio J.; Cunha, Katia; da Costa, Luiz N.; Da Rio, Nicola; Davenport, James R. A.; Dawson, Kyle S.; De Lee, Nathan; Delubac, Timothée; Deshpande, Rohit; Dhital, Saurav; Dutra-Ferreira, Letícia; Dwelly, Tom; Ealet, Anne; Ebelke, Garrett L.; Edmondson, Edward M.; Eisenstein, Daniel J.; Ellsworth, Tristan; Elsworth, Yvonne; Epstein, Courtney R.; Eracleous, Michael; Escoffier, Stephanie; Esposito, Massimiliano; Evans, Michael L.; Fan, Xiaohui; Fernández-Alvar, Emma; Feuillet, Diane; Filiz Ak, Nurten; Finley, Hayley; Finoguenov, Alexis; Flaherty, Kevin; Fleming, Scott W.; Font-Ribera, Andreu; Foster, Jonathan; Frinchaboy, Peter M.; Galbraith-Frew, J. G.; García, Rafael A.; García-Hernández, D. A.; García Pérez, Ana E.; Gaulme, Patrick; Ge, Jian; Génova-Santos, R.; Georgakakis, A.; Ghezzi, Luan; Gillespie, Bruce A.; Girardi, Léo; Goddard, Daniel; Gontcho, Satya Gontcho A.; González Hernández, Jonay I.; Grebel, Eva K.; Green, Paul J.; Grieb, Jan Niklas; Grieves, Nolan; Gunn, James E.; Guo, Hong; Harding, Paul; Hasselquist, Sten; Hawley, Suzanne L.; Hayden, Michael; Hearty, Fred R.; Hekker, Saskia; Ho, Shirley; Hogg, David W.; Holley-Bockelmann, Kelly; Holtzman, Jon A.; Honscheid, Klaus; Huber, Daniel; Huehnerhoff, Joseph; Ivans, Inese I.; Jiang, Linhua; Johnson, Jennifer A.; Kinemuchi, Karen; Kirkby, David; Kitaura, Francisco; Klaene, Mark A.; Knapp, Gillian R.; Kneib, Jean-Paul; Koenig, Xavier P.; Lam, Charles R.; Lan, Ting-Wen; Lang, Dustin; Laurent, Pierre; Le Goff, Jean-Marc; Leauthaud, Alexie; Lee, Khee-Gan; Lee, Young Sun; Licquia, Timothy C.; Liu, Jian; Long, Daniel C.; López-Corredoira, Martín; Lorenzo-Oliveira, Diego; Lucatello, Sara; Lundgren, Britt; Lupton, Robert H.; Mack, Claude E., III; Mahadevan, Suvrath; Maia, Marcio A. G.; Majewski, Steven R.; Malanushenko, Elena; Malanushenko, Viktor; Manchado, A.; Manera, Marc; Mao, Qingqing; Maraston, Claudia; Marchwinski, Robert C.; Margala, Daniel; Martell, Sarah L.; Martig, Marie; Masters, Karen L.; Mathur, Savita; McBride, Cameron K.; McGehee, Peregrine M.; McGreer, Ian D.; McMahon, Richard G.; Ménard, Brice; Menzel, Marie-Luise; Merloni, Andrea; Mészáros, Szabolcs; Miller, Adam A.; Miralda-Escudé, Jordi; Miyatake, Hironao; Montero-Dorta, Antonio D.; More, Surhud; Morganson, Eric; Morice-Atkinson, Xan; Morrison, Heather L.; Mosser, Benôit; Muna, Demitri; Myers, Adam D.; Nandra, Kirpal; Newman, Jeffrey A.; Neyrinck, Mark; Nguyen, Duy Cuong; Nichol, Robert C.; Nidever, David L.; Noterdaeme, Pasquier; Nuza, Sebastián E.; O'Connell, Julia E.; O'Connell, Robert W.; O'Connell, Ross; Ogando, Ricardo L. C.; Olmstead, Matthew D.; Oravetz, Audrey E.; Oravetz, Daniel J.; Osumi, Keisuke; Owen, Russell; Padgett, Deborah L.; Padmanabhan, Nikhil; Paegert, Martin; Palanque-Delabrouille, Nathalie; Pan, Kaike; Parejko, John K.; Pâris, Isabelle; Park, Changbom; Pattarakijwanich, Petchara; Pellejero-Ibanez, M.; Pepper, Joshua; Percival, Will J.; Pérez-Fournon, Ismael; Pérez-Ràfols, Ignasi; Petitjean, Patrick; Pieri, Matthew M.; Pinsonneault, Marc H.; Porto de Mello, Gustavo F.; Prada, Francisco; Prakash, Abhishek; Price-Whelan, Adrian M.; Protopapas, Pavlos; Raddick, M. Jordan; Rahman, Mubdi; Reid, Beth A.; Rich, James; Rix, Hans-Walter; Robin, Annie C.; Rockosi, Constance M.; Rodrigues, Thaíse S.; Rodríguez-Torres, Sergio; Roe, Natalie A.; Ross, Ashley J.; Ross, Nicholas P.; Rossi, Graziano; Ruan, John J.; Rubiño-Martín, J. A.; Rykoff, Eli S.; Salazar-Albornoz, Salvador; Salvato, Mara; Samushia, Lado; Sánchez, Ariel G.; Santiago, Basílio; Sayres, Conor; Schiavon, Ricardo P.; Schlegel, David J.; Schmidt, Sarah J.; Schneider, Donald P.; Schultheis, Mathias; Schwope, Axel D.; Scóccola, C. G.; Scott, Caroline; Sellgren, Kris; Seo, Hee-Jong; Serenelli, Aldo; Shane, Neville; Shen, Yue; Shetrone, Matthew; Shu, Yiping; Silva Aguirre, V.; Sivarani, Thirupathi; Skrutskie, M. F.; Slosar, Anže; Smith, Verne V.; Sobreira, Flávia; Souto, Diogo; Stassun, Keivan G.; Steinmetz, Matthias; Stello, Dennis; Strauss, Michael A.; Streblyanska, Alina; Suzuki, Nao; Swanson, Molly E. C.; Tan, Jonathan C.; Tayar, Jamie; Terrien, Ryan C.; Thakar, Aniruddha R.; Thomas, Daniel; Thomas, Neil; Thompson, Benjamin A.; Tinker, Jeremy L.; Tojeiro, Rita; Troup, Nicholas W.; Vargas-Magaña, Mariana; Vazquez, Jose A.; Verde, Licia; Viel, Matteo; Vogt, Nicole P.; Wake, David A.; Wang, Ji; Weaver, Benjamin A.; Weinberg, David H.; Weiner, Benjamin J.; White, Martin; Wilson, John C.; Wisniewski, John P.; Wood-Vasey, W. M.; Ye`che, Christophe; York, Donald G.; Zakamska, Nadia L.; Zamora, O.; Zasowski, Gail; Zehavi, Idit; Zhao, Gong-Bo; Zheng, Zheng; Zhou, Xu; Zhou, Zhimin; Zou, Hu; Zhu, Guangtun Bibcode: 2015ApJS..219...12A Altcode: 2015arXiv150100963A The third generation of the Sloan Digital Sky Survey (SDSS-III) took data from 2008 to 2014 using the original SDSS wide-field imager, the original and an upgraded multi-object fiber-fed optical spectrograph, a new near-infrared high-resolution spectrograph, and a novel optical interferometer. All of the data from SDSS-III are now made public. In particular, this paper describes Data Release 11 (DR11) including all data acquired through 2013 July, and Data Release 12 (DR12) adding data acquired through 2014 July (including all data included in previous data releases), marking the end of SDSS-III observing. Relative to our previous public release (DR10), DR12 adds one million new spectra of galaxies and quasars from the Baryon Oscillation Spectroscopic Survey (BOSS) over an additional 3000 deg2 of sky, more than triples the number of H-band spectra of stars as part of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE), and includes repeated accurate radial velocity measurements of 5500 stars from the Multi-object APO Radial Velocity Exoplanet Large-area Survey (MARVELS). The APOGEE outputs now include the measured abundances of 15 different elements for each star. In total, SDSS-III added 5200 deg2 of ugriz imaging; 155,520 spectra of 138,099 stars as part of the Sloan Exploration of Galactic Understanding and Evolution 2 (SEGUE-2) survey; 2,497,484 BOSS spectra of 1,372,737 galaxies, 294,512 quasars, and 247,216 stars over 9376 deg2; 618,080 APOGEE spectra of 156,593 stars; and 197,040 MARVELS spectra of 5513 stars. Since its first light in 1998, SDSS has imaged over 1/3 of the Celestial sphere in five bands and obtained over five million astronomical spectra. Title: Detecting Differential Rotation and Starspot Evolution on the M Dwarf GJ 1243 with Kepler Authors: Davenport, James R. A.; Hebb, Leslie; Hawley, Suzanne L. Bibcode: 2015ApJ...806..212D Altcode: 2015arXiv150501524D We present an analysis of the starspots on the active M4 dwarf GJ 1243, using 4 years of time series photometry from Kepler. A rapid P = 0.592596 ± 0.00021 days rotation period is measured due to the ∼2.2% starspot-induced flux modulations in the light curve. We first use a light curve modeling approach, using a Monte Carlo Markov Chain sampler to solve for the longitudes and radii of the two spots within 5 day windows of data. Within each window of time the starspots are assumed to be unchanging. Only a weak constraint on the starspot latitudes can be implied from our modeling. The primary spot is found to be very stable over many years. A secondary spot feature is present in three portions of the light curve, decays on 100-500 day timescales, and moves in longitude over time. We interpret this longitude shearing as the signature of differential rotation. Using our models we measure an average shear between the starspots of 0.0047 rad day-1, which corresponds to a differential rotation rate of Δ{Ω } = 0.012 ± 0.002 rad day-1. We also fit this starspot phase evolution using a series of bivariate Gaussian functions, which provides a consistent shear measurement. This is among the slowest differential rotation shear measurements yet measured for a star in this temperature regime, and provides an important constraint for dynamo models of low-mass stars. Title: The Time Domain Spectroscopic Survey: Variable Selection and Anticipated Results Authors: Morganson, Eric; Green, Paul J.; Anderson, Scott F.; Ruan, John J.; Myers, Adam D.; Eracleous, Michael; Kelly, Brandon; Badenes, Carlos; Bañados, Eduardo; Blanton, Michael R.; Bershady, Matthew A.; Borissova, Jura; Brandt, William Nielsen; Burgett, William S.; Chambers, Kenneth; Draper, Peter W.; Davenport, James R. A.; Flewelling, Heather; Garnavich, Peter; Hawley, Suzanne L.; Hodapp, Klaus W.; Isler, Jedidah C.; Kaiser, Nick; Kinemuchi, Karen; Kudritzki, Rolf P.; Metcalfe, Nigel; Morgan, Jeffrey S.; Pâris, Isabelle; Parvizi, Mahmoud; Poleski, Radosław; Price, Paul A.; Salvato, Mara; Shanks, Tom; Schlafly, Eddie F.; Schneider, Donald P.; Shen, Yue; Stassun, Keivan; Tonry, John T.; Walter, Fabian; Waters, Chris Z. Bibcode: 2015ApJ...806..244M Altcode: 2015arXiv150500760M We present the selection algorithm and anticipated results for the Time Domain Spectroscopic Survey (TDSS). TDSS is an Sloan Digital Sky Survey (SDSS)-IV Extended Baryon Oscillation Spectroscopic Survey (eBOSS) subproject that will provide initial identification spectra of approximately 220,000 luminosity-variable objects (variable stars and active galactic nuclei across 7500 deg2 selected from a combination of SDSS and multi-epoch Pan-STARRS1 photometry. TDSS will be the largest spectroscopic survey to explicitly target variable objects, avoiding pre-selection on the basis of colors or detailed modeling of specific variability characteristics. Kernel Density Estimate analysis of our target population performed on SDSS Stripe 82 data suggests our target sample will be 95% pure (meaning 95% of objects we select have genuine luminosity variability of a few magnitudes or more). Our final spectroscopic sample will contain roughly 135,000 quasars and 85,000 stellar variables, approximately 4000 of which will be RR Lyrae stars which may be used as outer Milky Way probes. The variability-selected quasar population has a smoother redshift distribution than a color-selected sample, and variability measurements similar to those we develop here may be used to make more uniform quasar samples in large surveys. The stellar variable targets are distributed fairly uniformly across color space, indicating that TDSS will obtain spectra for a wide variety of stellar variables including pulsating variables, stars with significant chromospheric activity, cataclysmic variables, and eclipsing binaries. TDSS will serve as a pathfinder mission to identify and characterize the multitude of variable objects that will be detected photometrically in even larger variability surveys such as Large Synoptic Survey Telescope. Title: Characterizing the Habitable Zones of Exoplanetary Systems with a Large Ultraviolet/Visible/Near-IR Space Observatory Authors: France, Kevin; Shkolnik, Evgenya; Linsky, Jeffrey; Roberge, Aki; Ayres, Thomas; Barman, Travis; Brown, Alexander; Davenport, James; Desert, Jean-Michel; Domagal-Goldman, Shawn; Fleming, Brian; Fontenla, Juan; Fossati, Luca; Froning, Cynthia; Hallinan, Gregg; Hawley, Suzanne; Hu, Renyu; Kaltenegger, Lisa; Kasting, James; Kowlaski, Adam; Loyd, Parke; Mauas, Pablo; Miguel, Yamila; Osten, Rachel; Redfield, Seth; Rugheimer, Sarah; Schneider, Christian; Segura, Antigona; Stocke, John; Tian, Feng; Tumlinson, Jason; Vieytes, Mariela; Walkowicz, Lucianne; Wood, Brian; Youngblood, Allison Bibcode: 2015arXiv150501840F Altcode: Understanding the surface and atmospheric conditions of Earth-size, rocky planets in the habitable zones (HZs) of low-mass stars is currently one of the greatest astronomical endeavors. Knowledge of the planetary effective surface temperature alone is insufficient to accurately interpret biosignature gases when they are observed in the coming decades. The UV stellar spectrum drives and regulates the upper atmospheric heating and chemistry on Earth-like planets, is critical to the definition and interpretation of biosignature gases, and may even produce false-positives in our search for biologic activity. This white paper briefly describes the scientific motivation for panchromatic observations of exoplanetary systems as a whole (star and planet), argues that a future NASA UV/Vis/near-IR space observatory is well-suited to carry out this work, and describes technology development goals that can be achieved in the next decade to support the development of a UV/Vis/near-IR flagship mission in the 2020s. Title: BOSS Ultracool Dwarfs. I. Colors and Magnetic Activity of M and L Dwarfs Authors: Schmidt, Sarah J.; Hawley, Suzanne L.; West, Andrew A.; Bochanski, John J.; Davenport, James R. A.; Ge, Jian; Schneider, Donald P. Bibcode: 2015AJ....149..158S Altcode: 2014arXiv1410.0014S We present the colors and activity of ultracool (M7-L8) dwarfs from the Tenth Data Release of the Sloan Digital Sky Survey (SDSS). We combine previous samples of SDSS M and L dwarfs with new data obtained from the Baryon Oscillation Sky Survey (BOSS) to produce the BOSS Ultracool Dwarf (BUD) sample of 11820 M7-L8 dwarfs. By combining SDSS data with photometry from 2MASS and the Wide-field Infrared Sky Explorer (WISE) mission, we present ultracool dwarf colors from i-z to W2-W3 as a function of spectral type, and extend the SDSS-2MASS-WISE color locus to include ultracool dwarfs. The i-z, i-J, and z-J colors provide the best indication of spectral type for M7-L3 dwarfs. We also examine ultracool dwarf chromospheric activity through the presence and strength of Hα emission. The fraction of active dwarfs rises through the M spectral sequence until it reaches ∼90% at spectral type L0. The fraction of active dwarfs then declines to 50% at spectral type L5; no Hα emission is observed in the late-L dwarfs in the BUD sample. The fraction of active L0-L5 dwarfs is much higher than previously observed. The strength of activity declines with spectral type from M7 through L3, after which the data do not show a clear trend. Using one-dimensional chromosphere models, we explore the range of filling factors and chromospheric temperature structures that are consistent with Hα observations of M0-L7 dwarfs. M dwarf chromospheres have a similar, smoothly varying range of temperature and surface coverage, while L dwarf chromospheres are cooler and have smaller filling factors. Title: State-of-the-Art Observations and Modeling of Stellar Flares Authors: Kowalski, Adam F.; Hawley, Suzanne L. Bibcode: 2015HiA....16...99K Altcode: Flares are observed on a wide variety of stellar types, ranging from closely orbiting binary systems consisting of an evolved member (RS CVn's) and young, nearby super-active M dwarfs (dMe's). The timescales and energies of flares span many orders of magnitude and typically far exceed the scales of even the largest solar flares observed. In particular, the active M dwarfs produce an energetic signature in the near-UV and optical continuum, which is often referred to as the white-light continuum. White-light emission has been studied in Johnson UBVR filters during a few large-amplitude flares, and the best emission mechanism that fits the broadband color distribution is a T~104 K blackbody (Hawley & Fisher 1992). Time-resolved blue spectra have revealed a consistent picture, with little or no Balmer jump and a smoothly rising continuum toward the near-UV (Hawley & Pettersen 1991). However, the most recent self-consistent radiative-hydrodynamic (RHD) models, which use a solar-type flare heating function from accelerated, nonthermal electrons, do not reproduce this emission spectrum. Instead, these models predict that the white-light is dominated by Balmer continuum emission from Hydrogen recombination in the chromosphere (Allred et al. 2006). Moreover, Allred et al. (2006) showed that the Johnson colors of the model prediction exhibit a broadband distribution similar to a blackbody with T~9000 K. Title: Serendipitous Discovery of a Dwarf Nova in the Kepler Field Near the G Dwarf KIC 5438845 Authors: Brown, Alexander; Neff, James E.; Ayres, Thomas R.; Kowalski, Adam; Hawley, Suzanne; Berdyugina, Svetlana; Harper, Graham M.; Korhonen, Heidi; Piskunov, Nikolai; Saar, Steven; Walkowicz, Lucianne; Wells, Mark A. Bibcode: 2015AJ....149...67B Altcode: The Kepler satellite provides a unique window into stellar temporal variability by observing a wide variety of stars with multi-year, near-continuous, high precision, optical photometric time series. While most Kepler targets are faint stars with poorly known physical properties, many unexpected discoveries should result from a long photometric survey of such a large area of sky. During our Kepler Guest Observer programs that monitored late-type stars for starspot and flaring variability, we discovered a previously unknown dwarf nova that lies within a few arcseconds of the mid-G dwarf star KIC 5438845. This dwarf nova underwent nine outbursts over a 4 year time span. The two largest outbursts lasted ∼17-18 days and show strong modulations with a 110.8 minute period and a declining amplitude during the outburst decay phase. These properties are characteristic of an SU UMa-type cataclysmic variable. By analogy with other dwarf nova light curves, we associate the 110.8 minute (1.847 hr) period with the superhump period, close to but slightly longer than the orbital period of the binary. No precursor outbursts are seen before the super-outbursts and the overall super-outburst morphology corresponds to Osaki & Meyer “Case B” outbursts, which are initiated when the outer edge of the disk reaches the tidal truncation radius. “Case B” outbursts are rare within the Kepler light curves of dwarf novae. The dwarf nova is undergoing relatively slow mass transfer, as evidenced by the long intervals between outbursts, but the mass transfer rate appears to be steady, because the smaller “normal” outbursts show a strong correlation between the integrated outburst energy and the elapsed time since the previous outburst. At super-outburst maximum the system was at V ∼ 18, but in quiescence it is fainter than V ∼ 22, which will make any detailed quiescent follow-up of this system difficult. Title: Kepler Flares III: Stellar Activity on GJ 1245A and B Authors: Lurie, John C.; Davenport, James R. A.; Hawley, Suzanne L.; Wilkinson, Tessa D.; Wisniewski, John P.; Kowalski, Adam F.; Hebb, Leslie Bibcode: 2015ApJ...800...95L Altcode: 2014arXiv1412.6109L We present the flare occurrence rates and starspot evolution for GJ 1245A and B, two active M5 stars, based on nine months of Kepler short cadence observations, and four years of nearly continuous long cadence observations. The A component is separated from the B component by 7'', and the stars are not resolved in the Kepler pipeline processing due to Kepler's large plate scale of 4'' pixel-1. Analyzing the target pixel data, we have generated separate light curves for components A and B using the PyKE pixel response function modeling procedures, and note the effects of CCD saturation and nonlinear response to high-energy flares. In our sample, GJ 1245A and B exhibit an average of 3.0 and 2.6 flares per day, respectively. We introduce a new metric, Lfl /L Kp, to compare the flare rates between stars, and discuss this in the context of GJ 1245A and B. Both stars exhibit starspot features that evolve on long timescales, with the slower rotating B component showing evidence of differential rotation. Intriguingly, the angular separation between the A and B component photocenters decreases during the four years of observations in a manner consistent with a shift in the position of the A photocenter due to the orbit of its unseen M8 companion (GJ 1245C), which is ~94% less bright. Among the most detailed photometric studies of fully convective M dwarfs in a multiple system, these results provide an important constraint on stellar age-rotation-activity models. Title: Flare Rate and Statistics for the M Dwarf GJ 1243 With Kepler Authors: Johnson, Emily; Davenport, James R. A.; Hawley, Suzanne L. Bibcode: 2015AAS...22523902J Altcode: Light curve data taken from the Kepler space telescope have been used to detect stellar flares. These data are a valuable resource for the study of flare rates and morphology, but currently flare samples must be validated by hand. FBEye (Flares By Eye) is an interactive program created to detect and manually validate these flares, with the goal of removing the need for human input. As a first year undergraduate student, I participated in this project by analyzing Kepler light curves and vetting stellar flares. Using 11 months of one-minute cadence data from GJ 1243, an M dwarf star, we classified each flare by energy and morphology. This work has been used to refine the FBEye program, which will eventually be applied to the entire catalogue of Kepler data. It is also part of a research paper on GJ 1243, which is currently in the publication process. Title: Time-Resolved Near-Ultraviolet Flare Spectra with the Hubble Space Telescope / Cosmic Origins Spectrograph Authors: Kowalski, Adam F.; Hawley, Suzanne L.; Johns-Krull, Christopher M.; Schmidt, Sarah J.; Brown, Alexander; Wisniewski, John P.; Davenport, James R. A.; Farina, Cecilia; Pietro Gentile Fusillo, Nicola; Xilouris, Manolis; Mathioudakis, Mihalis; Osten, Rachel A.; Holtzman, Jon A.; Phan-Bao, Ngoc; Valenti, Jeff A.; Walkowicz, Lucianne Bibcode: 2015AAS...22544903K Altcode: A large amount of the radiated energy during solar and stellar flares is emitted as white-light continuum emission, extending through the ultraviolet and optical wavelength regimes. Broadband photometry and optical spectral observations of M dwarf flares suggest that the white-light peak is located in the near-ultraviolet wavelength regime similar to a blackbody with T ~ 10,000 K, whereas radiative-hydrodynamic models using a solar-type flare heating mechanism (nonthermal electrons with a flux ~ 1011 erg / s / cm2 accelerated in the corona) predict that the peak lies at redder wavelengths at the head of the Balmer continuum. We have completed a successful flare monitoring campaign on the dM4e star GJ 1243, in order to constrain the time-evolution of the peak of the white-light continuum. The campaign took place over 12 hours on Aug 31/Sept 1, 2014, and included optical monitoring from nine ground-based telescopes as the Hubble Space Telescope recorded time-tagged spectra in the near-ultraviolet (2450-2840 Å) with the Cosmic Origins Spectrograph. Two flares occurred during the HST observations, and we show preliminary results relating the continuum and line (Fe II and Mg II) emission to the simultaneous ground-based optical spectra and photometry. This dataset provides new constraints for radiative-hydrodynamic modeling of the lower flaring atmosphere in addition to input for models of the effects of flares on biomarkers and habitability around M dwarfs. Title: The Continued Optical to Mid-Infrared Evolution of V838 Monocerotis Authors: Loebman, S. R.; Wisniewski, J. P.; Schmidt, S. J.; Kowalski, A. F.; Barry, R. K.; Bjorkman, K. S.; Hammel, H. B.; Hawley, S. L.; Hebb, L.; Kasliwal, M. M.; Lynch, D. K.; Russell, R. W.; Sitko, M. L.; Szkody, P. Bibcode: 2015AJ....149...17L Altcode: 2014arXiv1409.2513L The eruptive variable V838 Monocerotis (V838 Mon) gained notoriety in 2002 when it brightened nine magnitudes in a series of three outbursts and then rapidly evolved into an extremely cool supergiant. We present optical, near-infrared (near-IR), and mid-IR spectroscopic and photometric observations of V838 Mon obtained between 2008 and 2012 at the Apache Point Observatory 3.5 m, NASA IRTF 3 m, and Gemini South 8 m telescopes. We contemporaneously analyze the optical and IR spectroscopic properties of V838 Mon to arrive at a revised spectral type L3 supergiant and effective temperature {{T}eff}∼ 2000-2200 K. Because there are no existing optical observational data for L supergiants, we speculate that V838 Mon may represent the prototype for L supergiants in this wavelength regime. We find a low level of Hα emission present in the system, consistent with interaction between V838 Mon and its B3V binary; however, we cannot rule out a stellar collision as the genesis event, which could result in the observed Hα activity. Based upon a two-component blackbody fit to all wavelengths of our data, we conclude that, as of 2009, a shell of ejecta surrounded V838 Mon at a radius of R=263+/- 10 AU with a temperature of T=285+/- 2 K. This result is consistent with IR interferometric observations from the same era and predictions from the Lynch et al. model of the expanding system, which provides a simple framework for understanding this complicated system.

This publication is partially based on observations obtained with the Apache Point Observatory 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium. Title: The Stellar Activity of an M Dwarf Binary from Deconvolved Kepler Light Curves Authors: Lurie, John C.; Davenport, James R. A.; Hawley, Suzanne L.; Wilkinson, Tessa D. Bibcode: 2015AAS...22522906L Altcode: The M5+M5 pair GJ 1245AB was monitored almost continuously by Kepler for four years, providing a unique opportunity to study the stellar activity of two coeval, nearly-equal mass M dwarfs that are fully convective. The stars are 7" apart on the sky, and separate light curves for each star cannot be generated via aperture photometry due to Kepler's large 4"/pixel plate scale. Instead, we generated separate light curves from the target pixel files using the PyKE pixel response function modeling procedures. Intriguingly, the angular separation of the two stars decreases over the four years of Kepler observations in a manner consistent with an astrometric perturbation from the much fainter, unseen M8 (GJ 1245C) companion to GJ 1245A. Analyzing the separated light curves, we observe long lived starspot features on both stars that evolve on multi-year timescales. Both stars flare at nearly the same rate, despite having rotation rates that differ by almost a factor of three. Consistent with recent studies of active M dwarf binaries, these results provide further insight into the roles of age and rotation rate in stellar activity. Title: The APOGEE Low-Mass Star Ancillary Project Authors: Blake, Cullen; Mahadevan, Suvrath; Deshpande, Rohit; Bender, Chad F.; Terrien, Ryan; Crepp, Justin R.; Carlberg, Joleen K.; Nidever, David L.; Stassun, Keivan; Hawley, Suzanne L.; Hearty, Fred; Allende-Prieto, Carlos Bibcode: 2015AAS...22530205B Altcode: As a high-resolution, near-infrared, fiber-fed instrument, APOGEE presents a unique opportunity to obtain multi-epoch radial velocity measurements of a large number of low-mass stars. These observations will reveal unseen companions, improving our understanding of stellar multiplicity at the bottom of the Main Sequence, and may even identify candidate sub-stellar companions. These same data contains an unprecedented wealth of information about the kinematics, rotation, and metallicities of these stars. I will describe the status of our Ancillary Science program, and ongoing efforts to get the best possible radial velocity precision from the APOGEE data. Title: Ground-based Data on Kepler Eclipsing Binaries Authors: Wilkinson, Tessa D.; Hawley, S. L.; Davenport, J. R. A.; Hebb, Leslie; Weisenburger, K. L.; Garofali, K.; Kruse, E.; Luger, R.; Lurie, J. C.; Morris, B. M.; Ruan, J. J.; Sanderbeck, P. U.; Suberlak, K.; Telford, O. G.; Windemuth, D. Bibcode: 2015AAS...22513830W Altcode: Kepler has provided precise photometry for more than 2500 eclipsing binaries, which may be used to obtain fundamental stellar parameters such as mass and radius. We report on the initial results of a new ground-based program at Apache Point Observatory and Manastash Ridge Observatory to obtain spectra and photometry of Kepler eclipsing binaries. We present multi-color light curves, radial velocites, and additional characterization of the stellar spectra. The new ground-based data will be used to inform modeling efforts for these objects (see companion poster by K. Weisenburger et al.). Title: Eclipsing the Need for Spectroscopy: Constraining Eclipsing Binary Parameters Using Only Kepler Photometry Authors: Weisenburger, Kolby L.; Windemuth, D.; Hawley, S.; Davenport, J. R. A.; Hebb, Leslie; Wilkinson, T. D.; Garofali, K.; Kruse, E.; Luger, R.; Lurie, J. C.; Morris, B. M.; Suberlak, K.; Telford, O.; Upton Sanderbeck, P. Bibcode: 2015AAS...22513829W Altcode: Eclipsing binary (EB) stars provide accurate measurements of stellar mass and radius and therefore play a critical role in constraining stellar evolution models. Despite their utility in understanding the distribution of stellar properties, previous studies have been limited by the observational challenges inherent to identifying and characterizing EBs, namely, the need for both high-cadence, continuous photometric monitoring and follow-up spectroscopy for radial velocity (RV) measurements. Fortunately, the time-resolved data from the Kepler mission offer a new opportunity to assemble large samples of EBs, as well as place preliminary constraints on their masses and radii without the need for additional observations. While current EB models (e.g., JKTEBOP) and Kepler photometric data alone can be used to produce estimates of stellar parameters, we investigate the accuracy of this method by solving for orbital solutions with and without additional ground-based data (multi-color photometry and RVs). Here we present three Kepler EBs that have ground-based data from a new monitoring program recently initiated at Apache Point Observatory and Manastash Ridge Observatory (see corresponding poster by T. Wilkinson et al.), and use these systems to investigate any discrepancies between the two approaches. Considering the observational costs to targeting all Kepler EBs (> 2500) for ground-based follow-up, using select EBs such as these as test cases may allow for the development of a reliable method to determine stellar radii and temperatures exclusively from photometric data and thereby provide a useful tool for streamlining future EB analyses. Title: Using Transiting Planets to Model Starspot Evolution with Kepler Authors: Davenport, James R. A.; Hebb, Leslie; Hawley, Suzanne L. Bibcode: 2015AAS...22522907D Altcode: Photometry from Kepler has revealed the presence of cool starspots on the surfaces of thousands of stars, presenting a wide range of spot morphologies and lifetimes. Understanding the lifetime and evolution of starspots across the main sequence reveals critical information about the strength and nature of stellar dynamos. We probe the dynamo by modeling starspot features observed in Kepler light curves, using an MCMC-based light curve modeling code. We study planetary systems like Kepler 17, where spot-occulting transits probe smaller-scale starspot regions on the stellar surface along a fixed latitude region. Our approach is novel in modeling both the in- and out-of transit features in the light curve, allowing us to break fundamental degeneracies between spot size, latitude, and contrast. With continuous monitoring from Kepler we are able to observe small changes in the positions and sizes of spots from many transits, spanning 4 years of data. Additionally, for stars without transiting planets like GJ 1243, we are able to recover subtle, long term changes in spot sizes and longitudes, leading to the slowest differential rotation rate yet measured for a low mass star. These studies constrain properties that are key to understanding the stellar dynamo, including rotation period, differential rotation, and spot diffusion timescales. Title: Using Transiting Planets to Model Starspot Evolution Authors: Davenport, James R. A.; Hebb, Leslie; Hawley, Suzanne L. Bibcode: 2015csss...18..399D Altcode: 2014arXiv1408.5201D Photometry from Kepler has revealed the presence of cool starspots on the surfaces of thousands of stars, presenting a wide range of spot morphologies and lifetimes . Understanding the lifetime and evolution of starspots across the main sequence reveals critical information about the strength and nature of stellar dynamos. We probe the dynamo by modeling the starspot properties over time using Kepler light curves. In particular, we use planetary systems like Kepler 17 that show in-transit starspot crossing features. Spot-occulting transits probe smaller-scale starspot features on the stellar surface along a fixed latitude region. Our approach is novel in modeling both the in- and out-of transit light curve features, allowing us to break fundamental degeneracies between spot size, latitude, and contrast. With continuous monitoring from Kepler we are able to observe small changes in the positions and sizes of spots from many transits, spanning 4 years of data. Additionally, for stars without transiting planets like GJ 1243 we are able to recover subtle, long term changes in spot sizes and longitudes, leading to some of the slowest differential rotation rates yet measured. These studies constrain key physical parameters including rotation period, differential rotation, and diffusion timescales, and open the door to ensemble studies of detailed spot evolution in the future. Title: Hα Emission From Active Equal-Mass, Wide M Dwarf Binaries Authors: Gunning, Heather C.; Schmidt, Sarah J.; Davenport, James R. A.; Dhital, Saurav; Hawley, Suzanne L.; West, Andrew A. Bibcode: 2014PASP..126.1081G Altcode: 2014arXiv1410.1514G Not Available

This publication is partially based on observations obtained with the Apache Point Observatory 3.5-meter telescope, which is owned and operated by the Astrophysical Research Consortium. Title: Kepler Flares. II. The Temporal Morphology of White-light Flares on GJ 1243 Authors: Davenport, James R. A.; Hawley, Suzanne L.; Hebb, Leslie; Wisniewski, John P.; Kowalski, Adam F.; Johnson, Emily C.; Malatesta, Michael; Peraza, Jesus; Keil, Marcus; Silverberg, Steven M.; Jansen, Tiffany C.; Scheffler, Matthew S.; Berdis, Jodi R.; Larsen, Daniel M.; Hilton, Eric J. Bibcode: 2014ApJ...797..122D Altcode: 2014arXiv1411.3723D We present the largest sample of flares ever compiled for a single M dwarf, the active M4 star GJ 1243. Over 6100 individual flare events, with energies ranging from 1029 to 1033 erg, are found in 11 months of 1 minute cadence data from Kepler. This sample is unique for its completeness and dynamic range. We have developed automated tools for finding flares in short-cadence Kepler light curves, and performed extensive validation and classification of the sample by eye. From this pristine sample of flares we generate a median flare template. This template shows that two exponential cooling phases are present during the white-light flare decay, providing fundamental constraints for models of flare physics. The template is also used as a basis function to decompose complex multi-peaked flares, allowing us to study the energy distribution of these events. Only a small number of flare events are not well fit by our template. We find that complex, multi-peaked flares occur in over 80% of flares with a duration of 50 minutes or greater. The underlying distribution of flare durations for events 10 minutes and longer appears to follow a broken power law. Our results support the idea that sympathetic flaring may be responsible for some complex flare events. Title: Kepler Flares. I. Active and Inactive M Dwarfs Authors: Hawley, Suzanne L.; Davenport, James R. A.; Kowalski, Adam F.; Wisniewski, John P.; Hebb, Leslie; Deitrick, Russell; Hilton, Eric J. Bibcode: 2014ApJ...797..121H Altcode: 2014arXiv1410.7779H We analyzed Kepler short-cadence M dwarf observations. Spectra from the Astrophysical Research Consortium 3.5 m telescope identify magnetically active (Hα in emission) stars. The active stars are of mid-M spectral type, have numerous flares, and have well-defined rotational modulation due to starspots. The inactive stars are of early M type, exhibit less starspot signature, and have fewer flares. A Kepler to U-band energy scaling allows comparison of the Kepler flare frequency distributions with previous ground-based data. M dwarfs span a large range of flare frequency and energy, blurring the distinction between active and inactive stars designated solely by the presence of Hα. We analyzed classical and complex (multiple peak) flares on GJ 1243, finding strong correlations between flare energy, amplitude, duration, and decay time, with only a weak dependence on rise time. Complex flares last longer and have higher energy at the same amplitude, and higher energy flares are more likely to be complex. A power law fits the energy distribution for flares with log EK_p \gt 31 erg, but the predicted number of low-energy flares far exceeds the number observed, at energies where flares are still easily detectable, indicating that the power-law distribution may flatten at low energy. There is no correlation of flare occurrence or energy with starspot phase, the flare waiting time distribution is consistent with flares occurring randomly in time, and the energies of consecutive flares are uncorrelated. These observations support a scenario where many independent active regions on the stellar surface are contributing to the observed flare rate. Title: Calibrating Ultracool Dwarfs: Optical Template Spectra, Bolometric Corrections, and χ Values Authors: Schmidt, Sarah J.; West, Andrew A.; Bochanski, John J.; Hawley, Suzanne L.; Kielty, Collin Bibcode: 2014PASP..126..642S Altcode: 2014arXiv1406.1228S Not Available

This publication is partially based on observations obtained with the Apache Point Observatory 3.5 meter telescope, which is owned and operated by the Astrophysical Research Consortium. Title: The Hammer: An IDL Spectral Typing Suite Authors: Covey, Kevin R.; West, Andrew A.; Bochanski, John J.; Hawley, Suzanne L. Bibcode: 2014ascl.soft05003C Altcode: The Hammer can classify spectra in a variety of formats with targets spanning the MK spectral sequence. It processes a list of input spectra by automatically estimating each object's spectral type and measuring activity and metallicity tracers in late type stars. Once automatic processing is complete, an interactive interface allows the user to manually tweak the final assigned spectral type through visual comparison with a set of templates. Title: The Tenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Apache Point Observatory Galactic Evolution Experiment Authors: Ahn, Christopher P.; Alexandroff, Rachael; Allende Prieto, Carlos; Anders, Friedrich; Anderson, Scott F.; Anderton, Timothy; Andrews, Brett H.; Aubourg, Éric; Bailey, Stephen; Bastien, Fabienne A.; Bautista, Julian E.; Beers, Timothy C.; Beifiori, Alessandra; Bender, Chad F.; Berlind, Andreas A.; Beutler, Florian; Bhardwaj, Vaishali; Bird, Jonathan C.; Bizyaev, Dmitry; Blake, Cullen H.; Blanton, Michael R.; Blomqvist, Michael; Bochanski, John J.; Bolton, Adam S.; Borde, Arnaud; Bovy, Jo; Shelden Bradley, Alaina; Brandt, W. N.; Brauer, Dorothée; Brinkmann, J.; Brownstein, Joel R.; Busca, Nicolás G.; Carithers, William; Carlberg, Joleen K.; Carnero, Aurelio R.; Carr, Michael A.; Chiappini, Cristina; Chojnowski, S. Drew; Chuang, Chia-Hsun; Comparat, Johan; Crepp, Justin R.; Cristiani, Stefano; Croft, Rupert A. C.; Cuesta, Antonio J.; Cunha, Katia; da Costa, Luiz N.; Dawson, Kyle S.; De Lee, Nathan; Dean, Janice D. R.; Delubac, Timothée; Deshpande, Rohit; Dhital, Saurav; Ealet, Anne; Ebelke, Garrett L.; Edmondson, Edward M.; Eisenstein, Daniel J.; Epstein, Courtney R.; Escoffier, Stephanie; Esposito, Massimiliano; Evans, Michael L.; Fabbian, D.; Fan, Xiaohui; Favole, Ginevra; Femenía Castellá, Bruno; Fernández Alvar, Emma; Feuillet, Diane; Filiz Ak, Nurten; Finley, Hayley; Fleming, Scott W.; Font-Ribera, Andreu; Frinchaboy, Peter M.; Galbraith-Frew, J. G.; García-Hernández, D. A.; García Pérez, Ana E.; Ge, Jian; Génova-Santos, R.; Gillespie, Bruce A.; Girardi, Léo; González Hernández, Jonay I.; Gott, J. Richard, III; Gunn, James E.; Guo, Hong; Halverson, Samuel; Harding, Paul; Harris, David W.; Hasselquist, Sten; Hawley, Suzanne L.; Hayden, Michael; Hearty, Frederick R.; Herrero Davó, Artemio; Ho, Shirley; Hogg, David W.; Holtzman, Jon A.; Honscheid, Klaus; Huehnerhoff, Joseph; Ivans, Inese I.; Jackson, Kelly M.; Jiang, Peng; Johnson, Jennifer A.; Kinemuchi, K.; Kirkby, David; Klaene, Mark A.; Kneib, Jean-Paul; Koesterke, Lars; Lan, Ting-Wen; Lang, Dustin; Le Goff, Jean-Marc; Leauthaud, Alexie; Lee, Khee-Gan; Lee, Young Sun; Long, Daniel C.; Loomis, Craig P.; Lucatello, Sara; Lupton, Robert H.; Ma, Bo; Mack, Claude E., III; Mahadevan, Suvrath; Maia, Marcio A. G.; Majewski, Steven R.; Malanushenko, Elena; Malanushenko, Viktor; Manchado, A.; Manera, Marc; Maraston, Claudia; Margala, Daniel; Martell, Sarah L.; Masters, Karen L.; McBride, Cameron K.; McGreer, Ian D.; McMahon, Richard G.; Ménard, Brice; Mészáros, Sz.; Miralda-Escudé, Jordi; Miyatake, Hironao; Montero-Dorta, Antonio D.; Montesano, Francesco; More, Surhud; Morrison, Heather L.; Muna, Demitri; Munn, Jeffrey A.; Myers, Adam D.; Nguyen, Duy Cuong; Nichol, Robert C.; Nidever, David L.; Noterdaeme, Pasquier; Nuza, Sebastián E.; O'Connell, Julia E.; O'Connell, Robert W.; O'Connell, Ross; Olmstead, Matthew D.; Oravetz, Daniel J.; Owen, Russell; Padmanabhan, Nikhil; Palanque-Delabrouille, Nathalie; Pan, Kaike; Parejko, John K.; Parihar, Prachi; Pâris, Isabelle; Pepper, Joshua; Percival, Will J.; Pérez-Ràfols, Ignasi; Dotto Perottoni, Hélio; Petitjean, Patrick; Pieri, Matthew M.; Pinsonneault, M. H.; Prada, Francisco; Price-Whelan, Adrian M.; Raddick, M. Jordan; Rahman, Mubdi; Rebolo, Rafael; Reid, Beth A.; Richards, Jonathan C.; Riffel, Rogério; Robin, Annie C.; Rocha-Pinto, H. J.; Rockosi, Constance M.; Roe, Natalie A.; Ross, Ashley J.; Ross, Nicholas P.; Rossi, Graziano; Roy, Arpita; Rubiño-Martin, J. A.; Sabiu, Cristiano G.; Sánchez, Ariel G.; Santiago, Basílio; Sayres, Conor; Schiavon, Ricardo P.; Schlegel, David J.; Schlesinger, Katharine J.; Schmidt, Sarah J.; Schneider, Donald P.; Schultheis, Mathias; Sellgren, Kris; Seo, Hee-Jong; Shen, Yue; Shetrone, Matthew; Shu, Yiping; Simmons, Audrey E.; Skrutskie, M. F.; Slosar, Anže; Smith, Verne V.; Snedden, Stephanie A.; Sobeck, Jennifer S.; Sobreira, Flavia; Stassun, Keivan G.; Steinmetz, Matthias; Strauss, Michael A.; Streblyanska, Alina; Suzuki, Nao; Swanson, Molly E. C.; Terrien, Ryan C.; Thakar, Aniruddha R.; Thomas, Daniel; Thompson, Benjamin A.; Tinker, Jeremy L.; Tojeiro, Rita; Troup, Nicholas W.; Vandenberg, Jan; Vargas Magaña, Mariana; Viel, Matteo; Vogt, Nicole P.; Wake, David A.; Weaver, Benjamin A.; Weinberg, David H.; Weiner, Benjamin J.; White, Martin; White, Simon D. M.; Wilson, John C.; Wisniewski, John P.; Wood-Vasey, W. M.; Yèche, Christophe; York, Donald G.; Zamora, O.; Zasowski, Gail; Zehavi, Idit; Zhao, Gong-Bo; Zheng, Zheng; Zhu, Guangtun Bibcode: 2014ApJS..211...17A Altcode: 2013arXiv1307.7735A The Sloan Digital Sky Survey (SDSS) has been in operation since 2000 April. This paper presents the Tenth Public Data Release (DR10) from its current incarnation, SDSS-III. This data release includes the first spectroscopic data from the Apache Point Observatory Galaxy Evolution Experiment (APOGEE), along with spectroscopic data from the Baryon Oscillation Spectroscopic Survey (BOSS) taken through 2012 July. The APOGEE instrument is a near-infrared R ~ 22,500 300 fiber spectrograph covering 1.514-1.696 μm. The APOGEE survey is studying the chemical abundances and radial velocities of roughly 100,000 red giant star candidates in the bulge, bar, disk, and halo of the Milky Way. DR10 includes 178,397 spectra of 57,454 stars, each typically observed three or more times, from APOGEE. Derived quantities from these spectra (radial velocities, effective temperatures, surface gravities, and metallicities) are also included. DR10 also roughly doubles the number of BOSS spectra over those included in the Ninth Data Release. DR10 includes a total of 1,507,954 BOSS spectra comprising 927,844 galaxy spectra, 182,009 quasar spectra, and 159,327 stellar spectra selected over 6373.2 deg2. Title: Mapping small-scale starspots on Kepler transiting planet host stars Authors: Hebb, Leslie; Davenport, J. R.; Hawley, S. L.; Jardine, M. M.; Llama, J. Bibcode: 2014AAS...22344135H Altcode: High precision, near-continuous time series photometry of large numbers of transiting planet host stars is now available from the Kepler satellite archive. Using short cadence light curves of transiting planet host stars with sub-millimag photometric precision we are now, for the first time, able to map relative brightness variations due to small-scale starspots on the surfaces of stars other than the Sun. Here, we present a new project whose goal is to derive the detailed time evolution of the starspot distribution on the surface of tens of stars with a range of masses and rotation rates. We have developed an eclipse mapping code which we are using to determine the lifetime of individual starspots and starspot groups by identifying and modeling brightness variations during planetary transits caused by the planet crossing in front of a starspot on the stellar surface. In order to reduce the degeneracy of the light curve inversion problem, we are using precise knowledge of the planet's position and comprehensively modeling the in- and out- of transit data to strengthen the constraints on the positions of the surface spots. Here, we describe our overall project, explain our eclipse mapping technique in detail, and present preliminary results on the transiting planet host star, Kepler-17. Preliminary results on the spot evolution of additional systems (Kepler-17, Kepler-63, HAT-P-11, and GJ1243) are presented in a corresponding presentation by J.R.A. Davenport. Title: Double the Lightcurves, Double the Fun: Stellar Activity on the M Dwarfs GJ 1245 A and B with Kepler Authors: Lurie, John C.; Davenport, J. R.; Hawley, S. L. Bibcode: 2014AAS...22344140L Altcode: GJ 1245ABC is a nearby triple system comprised of two M5 components (A and B) and a very low mass stellar companion (C) to A. As a Kepler target, this system presents a unique opportunity to study the stellar activity of two coeval, nearly-equal mass M dwarfs. Components AC and B are separated by 7". Given Kepler's large plate scale of 4"/pixel, this system is not resolved in the Kepler pipeline processing. Time series analysis reveals two strong periodic signals due to starspots on components A and B, which have different rotation periods. The C component is ~3 magnitudes fainter than A, and as such does not contribute significantly to the flux from A. Examining the Kepler pixel files directly, we are able to use these periodic signals to disentangle the A and B components. Here we demonstrate this novel technique, and present preliminary separated lightcurves for GJ 1245 A and B. Ultimately, we will determine the individual flare occurrence rates for A and B, providing an important test for stellar age-activity-rotation models. Title: The Atmospheric Response to High Fluxes of Nonthermal Electrons during M Dwarf Flares Authors: Kowalski, Adam; Allred, J. C.; Carlsson, M.; Hawley, S. L.; Holman, G. D.; Mathioudakis, M.; Osten, R. A.; Uitenbroek, H. Bibcode: 2014AAS...22315117K Altcode: Flares are thought to be the result of magnetic fields in the stellar corona that undergo reconnection and accelerate charged particles into the lower atmosphere. Spectra of M dwarf flares in the optical and near-ultraviolet wavelength regimes can be used to constrain the heating mechanism of the lower stellar atmosphere. These observations show several ubiquitous properties of the continuum emission, which is not reproduced by models that use typical “solar-type” heating functions. We present results from a grid of new flare models using the RADYN code, which simultaneously calculates the radiative transfer and hydrodynamics on short timescales. We explore the atmospheric response to a short ~2 second burst of a very high heating rate from nonthermal electrons using a solar-type heating function, and we propose a new “M dwarf-type” heating variation that explains a range of observed spectral properties, such as ~10,000 K blackbody emission and a smooth continuum across the Balmer jump wavelength (3646A). Title: Using exoplanet systems with highly elliptical orbits to search for star-planet interactions Authors: Hodgson, John R.; Christian, Damian J.; Bodewits, Dennis; Hawley, Suzanne Bibcode: 2014IAUS..299..291H Altcode: We are investigating if the orbital geometry of exoplanets affects the activity of their host star by studying a sample of planetary systems known to contain massive planets on short period, highly elliptical orbits. While recent studies in the optical, UV, and X-Ray have shown enhanced chromospheric activity for stars hosting exoplanets with orbital semi-major axes less than 0.1 AU (Krejcova 2012, Shkolnik 2013, Kashyap 2008, Poppenhaeger 2010), it is not yet clear whether this activity is driven by magnetic or tidal interactions. We are probing the dependence of star-planet interactions (SPI) on the orbital geometry of the planetary systems by analyzing chromospheric lines (such as Ca II H & K) for variability phased with the exoplanet's orbit. We have obtained high resolution spectra of several systems with the McDonald 2.1-m Sandiford echelle spectrograph, ARCES on the APO 3.5-m, and for HIRES on Keck I from the Keck Observatory Archive. We describe our methodology and review how our results will use orbital geometry to deduce how planets may affect the activity of their host stars. Title: Tracing Detailed Starspot Evolution with Kepler Authors: Davenport, James R.; Hebb, L.; Hawley, S. L. Bibcode: 2014AAS...22331503D Altcode: Modeling sinusoidal flux variations in high precision photometry due to starspots, and their evolution over time, reveals critical information about the strength and nature of stellar magnetic fields. Photometry from the Kepler mission has discovered the presence of cool starspots on the surfaces of thousands of main sequence stars. Here we show preliminary results from our campaign to model the detailed time evolution of starspots on four stars. The rapidly rotating M4 star, GJ 1243, exhibits a remarkably stable polar starspot spanning three years of observation. A secondary polar spot is also seen, with an evolution timescale of hundreds of days. Three G/K stars with a wide range of rotation periods have also been studied, KOI-63, Kepler 17, and HAT-P-11. These systems all have planetary transits in their light curves, which we exploit to break degeneracies between spot surface coverage area and spot latitude. These transits can also probe smaller-scale starspot features on the stellar surface along a fixed latitude. By modeling the in- and out-of-eclipse light curves (see corresponding poster by L. Hebb) we are able to trace the detailed starspot evolution for several years in each system. This will help to constrain key physical parameters, such as mean rotation period, differential rotation, and diffusion timescales. Title: The properties of flare kernels observed by the Dunn Solar Telescope Authors: Fletcher, Lyndsay; Kowalski, A.; Cauzzi, G.; Hawley, S. L.; Hudson, H. S. Bibcode: 2013SPD....44...67F Altcode: We report on a campaign at the Dunn Solar Telescope which resulted in successful imaging and spectroscopic observations of a C1.1 solar flare on 18th August 2011. This flare exhibited ribbons with complicated fine structure at the resolution of the DST/IBIS instrument, and a number of bright kernels with sizes comparable to the smallest scales sampled by IBIS, around 2-4 pixels (0."3-0."6) FWHM. We focus on these bright kernels, describing their spatial characteristics in the core and wing of H alpha and Ca II 8542, and in the UV and EUV with SDO. We also show preliminary broad-band spectroscopy of the kernels which may demonstrate the presence of an optical continuum in this small flare. Title: Time-resolved Properties and Global Trends in dMe Flares from Simultaneous Photometry and Spectra Authors: Kowalski, Adam F.; Hawley, Suzanne L.; Wisniewski, John P.; Osten, Rachel A.; Hilton, Eric J.; Holtzman, Jon A.; Schmidt, Sarah J.; Davenport, James R. A. Bibcode: 2013ApJS..207...15K Altcode: 2013arXiv1307.2099K We present a homogeneous analysis of line and continuum emission from simultaneous high-cadence spectra and photometry covering near-ultraviolet and optical wavelengths for 20 M dwarf flares. These data were obtained to study the white-light continuum components at bluer and redder wavelengths than the Balmer jump. Our goals were to break the degeneracy between emission mechanisms that have been fit to broadband colors of flares and to provide constraints for radiative-hydrodynamic (RHD) flare models that seek to reproduce the white-light flare emission. The main results from the analysis are the following: (1) the detection of Balmer continuum (in emission) that is present during all flares and with a wide range of relative contributions to the continuum flux at bluer wavelengths than the Balmer jump; (2) a blue continuum at flare maximum that is linearly decreasing with wavelength from λ = 4000-4800 Å, indicative of hot, blackbody emission with typical temperatures of T BB ~ 9000-14, 000 K (3) a redder continuum apparent at wavelengths longer than Hβ (λ >~ 4900 Å) which becomes relatively more important to the energy budget during the late gradual phase. The hot blackbody component and redder continuum component have been detected in previous studies of flares. However, we have found that although the hot blackbody emission component is relatively well-represented by a featureless, single-temperature Planck function, this component includes absorption features and has a continuum shape strikingly similar to the spectrum of an A-type star as directly observed in our flare spectra. New model constraints are presented for the time evolution among the hydrogen Balmer lines and between Ca II K and the blackbody continuum emission. We calculate Balmer jump flux ratios and compare to the solar-type flare heating predictions from RHD models. The model ratios are too large and the blue-optical (λ = 4000-4800 Å) slopes are too red in both the impulsive and gradual decay phases of all 20 flares. This discrepancy implies that further work is needed to understand the heating at high column mass during dMe flares.

Based on observations obtained with the Apache Point Observatory 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium. Title: WIYN Observatory: Partnerships Authors: Hawley, Suzanne L.; Walterbos, R. A.; Gillespie, B. A. Bibcode: 2013AAS...22220404H Altcode: As part of its "meeting-in-a-meeting" highlighting the scientific contributions and the new instrumentation available at WIYN, the Observatory partners are providing a forum for discussion of potential partnership arrangements for national 4-meter class telescopes. In this session, WIYN and other operators of 4-meter class telescopes will join in a panel discussion that features their plans for the future, possible strategies for broadening the user base from the community, and potential synergies and partnerships with existing and planned large survey projects and facilities. This session is intended to facilitate a conversation within the national community that explores potential future partnership arrangements to provide stable operational models for moderate aperture facilities that currently serve a large user base in the US. Title: VizieR Online Data Catalog: M dwarf flare spectra (Kowalski+, 2013) Authors: Kowalski, A. F.; Hawley, S. L.; Wisniewski, J. P.; Osten, R. A.; Hilton, E. J.; Holtzman, J. A.; Schmidt, S. J.; Davenport, J. R. A. Bibcode: 2013yCat..22070015K Altcode: The spectral data are contained in FITS files (to be read into IDL with mrdfits.pro), and the photometry data are contained in two column .dat files.

Spectra were obtained with the Dual-Imaging Spectrograph (DIS) on the ARC 3.5m telescope at the Apache Point Observatory (APO) in low-resolution. The observing log for each target star is given in Table 2.

(5 data files). Title: The Very Short Period M Dwarf Binary SDSS J001641-000925 Authors: Davenport, James R. A.; Becker, Andrew C.; West, Andrew A.; Bochanski, John J.; Hawley, Suzanne L.; Holtzman, Jon; Gunning, Heather C.; Hilton, Eric J.; Munshi, Ferah A.; Albright, Meagan Bibcode: 2013ApJ...764...62D Altcode: 2012arXiv1206.6056D We present follow-up observations and analysis of the recently discovered short period low-mass eclipsing binary, SDSS J001641-000925. With an orbital period of 0.19856 days, this system has one of the shortest known periods for an M dwarf binary system. Medium-resolution spectroscopy and multi-band photometry for the system are presented. Markov Chain Monte Carlo modeling of the light curves and radial velocities yields estimated masses for the stars of M 1 = 0.54 ± 0.07 M ⊙ and M 2 = 0.34 ± 0.04 M ⊙, and radii of R 1 = 0.68 ± 0.03 R ⊙ and R 2 = 0.58 ± 0.03 R ⊙, respectively. This solution places both components above the critical Roche overfill limit, providing strong evidence that SDSS J001641-000925 is the first verified M-dwarf contact binary system. Within the follow-up spectroscopy we find signatures of non-solid body rotation velocities, which we interpret as evidence for mass transfer or loss within the system. In addition, our photometry samples the system over nine years, and we find strong evidence for period decay at the rate of \dot{P}\sim 8 s yr-1. Both of these signatures raise the intriguing possibility that the system is in over-contact, and actively losing angular momentum, likely through mass loss. This places SDSS J001641-000925 as not just the first M-dwarf over-contact binary, but one of the few systems of any spectral type known to be actively undergoing coalescence. Further study of SDSS J001641-000925 is ongoing to verify the nature of the system, which may prove to be a unique astrophysical laboratory.

Based on observations obtained with the Apache Point Observatory 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile. Support for the design and construction of the Magellan Echellette Spectrograph was received from the Observatories of the Carnegie Institution of Washington, the School of Science of the Massachusetts Institute of Technology, and the National Science Foundation in the form of a collaborative Major Research Instrument grant to Carnegie and MIT (AST0215989). Title: Measuring the ages of low-mass stars and brown dwarfs Authors: Bochanski, J. J.; Hawley, S. L.; Covey, K. R.; Agüeros, M. A.; Baraffe, I.; Catalán, S.; Mohanty, S.; Rice, E. L.; West, A. A. Bibcode: 2013AN....334...44B Altcode: 2013csss...17...44B Age is among the most elusive, yet important, fundamental properties of low-mass stars and brown dwarfs. M dwarfs have main-sequence lifetimes that are estimated to be trillions of years, with little change in luminosity. In contrast, brown dwarfs cool and dim with time, resulting in a significant degeneracy between mass, age, and luminosity. Despite these inherent challenges, there have been recent efforts on both observational and theoretical fronts that may yield precise ages for low-mass stars and brown dwarfs. We feature some current observational efforts focused on estimating ages of these objects as presented in our Cool Stars 17 splinter session. Title: MMT Hectochelle Spectral Variability of Active Late-type Stars in the Kepler Field (2013A) Authors: Brown, Alexander; Walkowicz, Lucianne; Saar, Steven; Hawley, Suzanne; Kowalski, Adam; Furesz, Gabor; Piskunov, Nikolai Bibcode: 2013noao.prop..286B Altcode: We have on-going it Kepler photometric monitoring of over 300 active late-type (mid-A - K) stars as part of our Cycles 1/2/3/4 Guest Observer (GO) programs with the aim of studying starspot evolution, differential rotation, activity cycles, and flares. We propose to use the MMT Hectochelle multiobject spectrograph to observe over 140 of these stars to determine a range of basic physical properties for the stars, such as radial velocity variations due to binarity, chromospheric activity levels from Ca II H+K and H(alpha), projected rotational velocities for comparison to the rotational periods measured directly by it Kepler, age/youth as indicated by Li I, and better effective temperature and luminosity estimates. In addition, to provide a superior sample for statistical studies another 800 GKM dwarf stars showing either starspot modulation from the it Kepler Team's data or from our deep XMM X-ray survey will be observed using the unassigned fibers in each field. These measurements require the 32,000 spectral resolution provided by Hectochelle, which is hard to obtain efficiently for 13-15th magnitude stars any other way. Title: Mapping the Local Halo: Statistical Parallax Analysis of SDSS Low-mass Subdwarfs Authors: Bochanski, John J.; Savcheva, Antonia; West, Andrew A.; Hawley, Suzanne L. Bibcode: 2013AJ....145...40B Altcode: 2012arXiv1211.6104B We present a statistical parallax study of nearly 2000 M subdwarfs with photometry and spectroscopy from the Sloan Digital Sky Survey (SDSS). Statistical parallax analysis yields the mean absolute magnitudes, mean velocities, and velocity ellipsoids for homogenous samples of stars. We selected homogeneous groups of subdwarfs based on their photometric colors and spectral appearance. We examined the color-magnitude relations of low-mass subdwarfs and quantified their dependence on the newly refined metallicity parameter, ζ. We also developed a photometric metallicity parameter, δ(g - r), based on the g - r and r - z colors of low-mass stars and used it to select stars with similar metallicities. The kinematics of low-mass subdwarfs as a function of color and metallicity were also examined and compared to main-sequence M dwarfs. We find that the SDSS subdwarfs share similar kinematics to the inner halo and thick disk. The color-magnitude relations derived in this analysis will be a powerful tool for identifying and characterizing low-mass metal-poor subdwarfs in future surveys such as Gaia and LSST, making them important and plentiful tracers of the stellar halo. Title: A Large Sample of Magnetically-Active Stars Observed With Kepler Authors: Wells, Mark; Neff, J. E.; Brown, A.; Ayres, T. R.; Basri, G. S.; Berdyugina, S.; Harper, G.; Hawley, S. L.; Korhonen, H.; Kowalski, A.; Micela, G.; Piskunov, N. E.; Ramsey, L. W.; Saar, S. H.; Walkowicz, L. M. Bibcode: 2013AAS...22135415W Altcode: We have observed about 325 stars in our Kepler Guest Observer programs (Cycles 1 through 4). For most of these targets, we are analyzing extremely high-precision light curves that have been continuously sampled every 30 minutes for up to 3 years. Our sample of candidate magnetically-active stars was selected primarily using GALEX colors. Starspots, pulsations, and variations due to eclipsing and contact binaries combine to produce a rich variety of light curves. We have developed semi-automated procedures to characterize this variability and thus to classify the targets and identify the physical mechanisms that dominate their Kepler light curves. We will describe these procedures and discuss the range of physical properties covered by our final classification scheme. We are using this Kepler database of variability over timescales of minutes to years to provide diagnostics of flares, starspot formation, evolution, migration, and ultimately of stellar cycles in general. This work contains results obtained using the NASA Kepler satellite and from the Apache Point Observatory, the MMT (using NOAO community access time), and the Hobby-Eberly Telescope. Funding is provided by NASA Kepler grants NNX10AC51G, NNX11AC79G, and NNX12AC85G to the University of Colorado, by NSF grant AST-1109695 to the College of Charleston, and by a grant from the South Carolina Space Grant consortium. Title: First Results From The BOSS Ultracool Dwarf (BUD) Sample Authors: Schmidt, Sarah J.; Hawley, S. L.; Davenport, J. R.; West, A. A.; Bochanski, J. J. Bibcode: 2013AAS...22115821S Altcode: We introduce the BOSS Ultracool Dwarf (BUD) sample of 12,085 M7-L8 dwarfs selected from the Sloan Digital Sky Survey (SDSS) photometry and spectroscopy. The BUD sample includes ultracool dwarfs selected from the SDSS seventh data release in addition to new dwarfs from the Baryon Oscillation Sky Survey (BOSS). We present the izJHKW1W2W3 color locus from a cross-match between the BUD sample and the 2MASS and WISE catalogs. In addition to colors, we also examine chromospheric activity based on the presence and strength of Hα emission. When we restrict our activity search to spectra with S/N > 3 in the region surrounding Hα, we find that over 80% of nearby early-L dwarfs are active. The fraction of active ultracool dwarfs is larger closer to the galactic plane, indicating that ultracool dwarfs follow an age activity relationship similar to more massive M dwarfs. Title: Young Star Populations in the Kepler Field Authors: Brown, Alexander; Neff, J. E.; Wells, M.; Saar, S.; Furesz, G.; Walkowicz, L. M.; Ayres, T. R.; Basri, G. S.; Berdyugina, S.; Harper, G.; Hawley, S. L.; Korhonen, H.; Kowalski, A.; Micela, G.; Piskunov, N. E.; Ramsey, L. W. Bibcode: 2013AAS...22135414B Altcode: The Kepler satellite is providing spectacular optical photometric light-curves of unprecedented precision and duration that routinely allow detailed studies of stellar magnetic activity on late-type stars that were difficult previously. Kepler provides multi-year duration light-curves that allow investigation of how activity phenomena -- such as the growth, migration, and decay of star-spots, differential rotation, activity cycles, and flaring -- operate on a wide variety of single and binary stars. The 105 square degree Kepler Field contains tens of thousands of late-type stars showing rotational modulation due to star-spots with periods ranging from one day to a ``solar-like'' month. Short rotation periods and high levels of magnetic activity are strongly correlated. However, there are only two basic reasons why stars with rotation periods of a few days possess such high angular momentum --- either they are close binaries or they are young stars. During Kepler GO Cycles 1 through 4 we have been studying the Long-cadence (30 minute sampling) photometry of hundreds of active late-type stars and as an absolutely essential complement we have been obtaining high resolution optical spectra to understand the physical properties of these stars. We present results from a spectroscopic survey using the MMT Hectochelle multi-object echelle of 4 square degrees of the Kepler Field. We have discovered a significant population of young stars with Li I absorption indicating ages of ~100 Myr or less at a spatial density of at least 20 stars per square degree. Our detected young star sample comprises at least 80 stars and represents a dramatic advance compared to the previously known sample over the full Kepler Field of three stars in this age range. Roughly one sixth of the stars observed are young and a similar number short-period binaries based on 2-4 radial velocities. We show how the rotational properties of the stars and their physical properties are related. This work is based on data obtained with the NASA Kepler satellite and the MMT Hectochelle spectrograph using NOAO community access time. Support by NASA Kepler grants to the University of Colorado and by NSF grant to the College of Charleston. Title: The Ninth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Baryon Oscillation Spectroscopic Survey Authors: Ahn, Christopher P.; Alexandroff, Rachael; Allende Prieto, Carlos; Anderson, Scott F.; Anderton, Timothy; Andrews, Brett H.; Aubourg, Éric; Bailey, Stephen; Balbinot, Eduardo; Barnes, Rory; Bautista, Julian; Beers, Timothy C.; Beifiori, Alessandra; Berlind, Andreas A.; Bhardwaj, Vaishali; Bizyaev, Dmitry; Blake, Cullen H.; Blanton, Michael R.; Blomqvist, Michael; Bochanski, John J.; Bolton, Adam S.; Borde, Arnaud; Bovy, Jo; Brandt, W. N.; Brinkmann, J.; Brown, Peter J.; Brownstein, Joel R.; Bundy, Kevin; Busca, N. G.; Carithers, William; Carnero, Aurelio R.; Carr, Michael A.; Casetti-Dinescu, Dana I.; Chen, Yanmei; Chiappini, Cristina; Comparat, Johan; Connolly, Natalia; Crepp, Justin R.; Cristiani, Stefano; Croft, Rupert A. C.; Cuesta, Antonio J.; da Costa, Luiz N.; Davenport, James R. A.; Dawson, Kyle S.; de Putter, Roland; De Lee, Nathan; Delubac, Timothée; Dhital, Saurav; Ealet, Anne; Ebelke, Garrett L.; Edmondson, Edward M.; Eisenstein, Daniel J.; Escoffier, S.; Esposito, Massimiliano; Evans, Michael L.; Fan, Xiaohui; Femenía Castellá, Bruno; Fernández Alvar, Emma; Ferreira, Leticia D.; Filiz Ak, N.; Finley, Hayley; Fleming, Scott W.; Font-Ribera, Andreu; Frinchaboy, Peter M.; García-Hernández, D. A.; García Pérez, A. E.; Ge, Jian; Génova-Santos, R.; Gillespie, Bruce A.; Girardi, Léo; González Hernández, Jonay I.; Grebel, Eva K.; Gunn, James E.; Guo, Hong; Haggard, Daryl; Hamilton, Jean-Christophe; Harris, David W.; Hawley, Suzanne L.; Hearty, Frederick R.; Ho, Shirley; Hogg, David W.; Holtzman, Jon A.; Honscheid, Klaus; Huehnerhoff, J.; Ivans, Inese I.; Ivezić, Željko; Jacobson, Heather R.; Jiang, Linhua; Johansson, Jonas; Johnson, Jennifer A.; Kauffmann, Guinevere; Kirkby, David; Kirkpatrick, Jessica A.; Klaene, Mark A.; Knapp, Gillian R.; Kneib, Jean-Paul; Le Goff, Jean-Marc; Leauthaud, Alexie; Lee, Khee-Gan; Lee, Young Sun; Long, Daniel C.; Loomis, Craig P.; Lucatello, Sara; Lundgren, Britt; Lupton, Robert H.; Ma, Bo; Ma, Zhibo; MacDonald, Nicholas; Mack, Claude E.; Mahadevan, Suvrath; Maia, Marcio A. G.; Majewski, Steven R.; Makler, Martin; Malanushenko, Elena; Malanushenko, Viktor; Manchado, A.; Mandelbaum, Rachel; Manera, Marc; Maraston, Claudia; Margala, Daniel; Martell, Sarah L.; McBride, Cameron K.; McGreer, Ian D.; McMahon, Richard G.; Ménard, Brice; Meszaros, Sz.; Miralda-Escudé, Jordi; Montero-Dorta, Antonio D.; Montesano, Francesco; Morrison, Heather L.; Muna, Demitri; Munn, Jeffrey A.; Murayama, Hitoshi; Myers, Adam D.; Neto, A. F.; Nguyen, Duy Cuong; Nichol, Robert C.; Nidever, David L.; Noterdaeme, Pasquier; Nuza, Sebastián E.; Ogando, Ricardo L. C.; Olmstead, Matthew D.; Oravetz, Daniel J.; Owen, Russell; Padmanabhan, Nikhil; Palanque-Delabrouille, Nathalie; Pan, Kaike; Parejko, John K.; Parihar, Prachi; Pâris, Isabelle; Pattarakijwanich, Petchara; Pepper, Joshua; Percival, Will J.; Pérez-Fournon, Ismael; Pérez-Ràfols, Ignasi; Petitjean, Patrick; Pforr, Janine; Pieri, Matthew M.; Pinsonneault, Marc H.; Porto de Mello, G. F.; Prada, Francisco; Price-Whelan, Adrian M.; Raddick, M. Jordan; Rebolo, Rafael; Rich, James; Richards, Gordon T.; Robin, Annie C.; Rocha-Pinto, Helio J.; Rockosi, Constance M.; Roe, Natalie A.; Ross, Ashley J.; Ross, Nicholas P.; Rossi, Graziano; Rubiño-Martin, J. A.; Samushia, Lado; Sanchez Almeida, J.; Sánchez, Ariel G.; Santiago, Basílio; Sayres, Conor; Schlegel, David J.; Schlesinger, Katharine J.; Schmidt, Sarah J.; Schneider, Donald P.; Schultheis, Mathias; Schwope, Axel D.; Scóccola, C. G.; Seljak, Uros; Sheldon, Erin; Shen, Yue; Shu, Yiping; Simmerer, Jennifer; Simmons, Audrey E.; Skibba, Ramin A.; Skrutskie, M. F.; Slosar, A.; Sobreira, Flavia; Sobeck, Jennifer S.; Stassun, Keivan G.; Steele, Oliver; Steinmetz, Matthias; Strauss, Michael A.; Streblyanska, Alina; Suzuki, Nao; Swanson, Molly E. C.; Tal, Tomer; Thakar, Aniruddha R.; Thomas, Daniel; Thompson, Benjamin A.; Tinker, Jeremy L.; Tojeiro, Rita; Tremonti, Christy A.; Vargas Magaña, M.; Verde, Licia; Viel, Matteo; Vikas, Shailendra K.; Vogt, Nicole P.; Wake, David A.; Wang, Ji; Weaver, Benjamin A.; Weinberg, David H.; Weiner, Benjamin J.; West, Andrew A.; White, Martin; Wilson, John C.; Wisniewski, John P.; Wood-Vasey, W. M.; Yanny, Brian; Yèche, Christophe; York, Donald G.; Zamora, O.; Zasowski, Gail; Zehavi, Idit; Zhao, Gong-Bo; Zheng, Zheng; Zhu, Guangtun; Zinn, Joel C. Bibcode: 2012ApJS..203...21A Altcode: 2012arXiv1207.7137S The Sloan Digital Sky Survey III (SDSS-III) presents the first spectroscopic data from the Baryon Oscillation Spectroscopic Survey (BOSS). This ninth data release (DR9) of the SDSS project includes 535,995 new galaxy spectra (median z ~ 0.52), 102,100 new quasar spectra (median z ~ 2.32), and 90,897 new stellar spectra, along with the data presented in previous data releases. These spectra were obtained with the new BOSS spectrograph and were taken between 2009 December and 2011 July. In addition, the stellar parameters pipeline, which determines radial velocities, surface temperatures, surface gravities, and metallicities of stars, has been updated and refined with improvements in temperature estimates for stars with T eff < 5000 K and in metallicity estimates for stars with [Fe/H] > -0.5. DR9 includes new stellar parameters for all stars presented in DR8, including stars from SDSS-I and II, as well as those observed as part of the SEGUE-2. The astrometry error introduced in the DR8 imaging catalogs has been corrected in the DR9 data products. The next data release for SDSS-III will be in Summer 2013, which will present the first data from the APOGEE along with another year of data from BOSS, followed by the final SDSS-III data release in 2014 December. Title: DRAFTS: A Deep, Rapid Archival Flare Transient Search in the Galactic Bulge Authors: Osten, Rachel A.; Kowalski, Adam; Sahu, Kailash; Hawley, Suzanne L. Bibcode: 2012ApJ...754....4O Altcode: 2012arXiv1205.1485O We utilize the Sagittarius Window Eclipsing Extrasolar Planet Search Hubble Space Telescope/Advanced Camera for Surveys data set for a Deep Rapid Archival Flare Transient Search to constrain the flare rate toward the older stellar population in the Galactic bulge. During seven days of monitoring 229,293 stars brighter than V = 29.5, we find evidence for flaring activity in 105 stars between V = 20 and V = 28. We divided the sample into non-variable stars and variable stars whose light curves contain large-scale variability. The flare rate on variable stars is ~700 times that of non-variable stars, with a significant correlation between the amount of underlying stellar variability and peak flare amplitude. The flare energy loss rates are generally higher than those of nearby well-studied single dMe flare stars. The distribution of proper motions is consistent with the flaring stars being at the distance and age of the Galactic bulge. If they are single dwarfs, then they span a range of ≈1.0-0.25 M ⊙. A majority of the flaring stars exhibit periodic photometric modulations with P < 3 days. If these are tidally locked magnetically active binary systems, then their fraction in the bulge is enhanced by a factor of ~20 compared to the local value. These stars may be useful for placing constraints on the angular momentum evolution of cool close binary stars. Our results expand the type of stars studied for flares in the optical band, and suggest that future sensitive optical time-domain studies will have to contend with a larger sample of flaring stars than the M dwarf flare stars usually considered. Title: MOST Observations of the Flare Star AD Leo Authors: Hunt-Walker, Nicholas M.; Hilton, Eric J.; Kowalski, Adam F.; Hawley, Suzanne L.; Matthews, Jaymie M. Bibcode: 2012PASP..124..545H Altcode: 2012arXiv1206.5019H We present continuous, high-precision photometric monitoring data with 1 minute cadence of the dM3e flare star AD Leo with the MOST satellite. We observed 19 flares in 5.8 days and found a flare frequency distribution that is similar to previous studies. The light curve reveals a sinusoidal modulation with a period of days that we attribute to the rotation of a stellar spot rotating into and out of view. We see no correlation between the occurrence of flares and rotational phase, indicating that there may be many spots distributed at different longitudes or, possibly, that the modulation is caused by varying surface coverage of a large polar spot that is viewed nearly pole-on. The data show no correlation between flare energy and the time since the previous flare. We use these results to reject a simple model in which all magnetic energy is stored in one active region and released only during flares.

Based on observations obtained with the Apache Point Observatory 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium. Title: Erratum: "The Luminosity and Mass Functions of Low-mass Stars in the Galactic Disk. II. The Field" (2010, AJ, 139, 2679) Authors: Bochanski, John J.; Hawley, Suzanne L.; Covey, Kevin R.; West, Andrew A.; Reid, I. Neill; Golimowski, David A.; Ivezić, Željko Bibcode: 2012AJ....143..152B Altcode: No abstract at ADS Title: Time-resolved NUV And Optical Spectra Of A Stellar Megaflare On YZ CMi With SALT/RSS Authors: Brown, Benjamin; Kowalski, A. F.; Mathioudakis, M.; Hooper, E. J.; Hawley, S. L.; Osten, R. A.; Wisniewski, J. P. Bibcode: 2012AAS...22020452B Altcode: The primary mode of radiative energy release in stellar flares is in the optical and near-ultraviolet (NUV) continuum. Active M-dwarf stares flare more frequently than the Sun, and their flares can be substantially more energetic. The dominant component in solar flare white light is thought to be Hydrogen recombination, whereas for stellar M dwarf flares, the dominant component is thought to be T 10,000 K blackbody emission. Recently we have obtained very high time-cadence spectral observations of the flaring M-dwarf YZ CMi (3200-6000A) using the Robert Stobie Spectrograph on the 11-meter South African Large Telescope (SALT/RSS), achieving 100x better temporal resolution than has previously been possible at the atmospheric limit. We observed a megaflare of over 100x flux enhancement in the NUV emission. Here we discuss the evolution of the stellar flare spectrum during the rapid impulsive phase of the flare and the implications for stellar flare models. Title: Using Kepler Data to Characterize the Flare Properties of GK Stars Authors: Kowalski, Adam F.; Deitrick, Russell J.; Brown, Alex; Davenport, Jim R. A.; Hawley, Suzanne L.; Hilton, Eric J.; Ayres, Thomas R.; Berdyugina, Svetlana V.; Harper, Graham M.; Korhonen, Heidi; Walkowicz, Lucianne M. Bibcode: 2012decs.confE.120K Altcode: Due to their high occurrence rate and large contrast against the background stellar emission, white-light flares on a handful of very active low-mass M stars have been the primary source for our understanding of optical flare emission. Kepler's high-precision, long baseline light curves have opened up the characterization of white-light emission to new domains of stars, including active G dwarfs. We present the properties of white-light flares on GALEX-selected solar-type stars from GO data in Q1-Q7. The flares are discussed in relation to intrinsic stellar properties, which are constrained by a vast amount of follow-up characterization of the sample. We compare the flare properties to large white-light flares observed on the Sun. These high-precision state-of-the-art observations will provide important constraints for models of internal magnetic dynamos and NLTE radiative-hydrodynamic simulations of energy deposition in the lower atmospheric layers. Title: Multi-wavelength Characterization of Stellar Flares on Low-mass Stars Using SDSS and 2MASS Time-domain Surveys Authors: Davenport, James R. A.; Becker, Andrew C.; Kowalski, Adam F.; Hawley, Suzanne L.; Schmidt, Sarah J.; Hilton, Eric J.; Sesar, Branimir; Cutri, Roc Bibcode: 2012ApJ...748...58D Altcode: 2012arXiv1202.1902D We present the first rates of flares from M dwarf stars in both red optical and near-infrared (NIR) filters. We have studied ~50,000 M dwarfs from the Sloan Digital Sky Survey (SDSS) Stripe 82 area and 1321 M dwarfs from the Two Micron All Sky Survey (2MASS) Calibration Scan Point Source Working Database that overlap SDSS imaging fields. We assign photometric spectral types from M0 to M6 using (r - i) and (i - z) colors for every star in our sample. Stripe 82 stars each have 50-100 epochs of data, while 2MASS Calibration stars have ~1900 epochs. From these data we estimate the observed rates and theoretical detection thresholds for flares in eight photometric bands as a function of spectral type. Optical flare rates are found to be in agreement with previous studies, while the frequency per hour of NIR flare detections is found to be more than two orders of magnitude lower. An excess of small-amplitude flux increases in all bands exhibits a power-law distribution, which we interpret as the result of flares below our detection thresholds. In order to investigate the recovery efficiency for flares in each filter, we extend a two-component flare model into the NIR. Quiescent M0-M6 spectral templates were used with the model to predict the photometric response of flares from u to Ks . We determine that red optical filters are sensitive to flares with u-band amplitudes gsim2 mag, and NIR filters to flares with Δu gsim 4.5 mag. Our model predicts that M0 stars have the best color contrast for J-band detections, but M4-M6 stars should yield the highest rate of NIR flares with amplitudes of ΔJ >= 0.01 mag. Characterizing flare rates and photometric variations at longer wavelengths is important for predicting the signatures of M dwarf variability in next-generation surveys, and we discuss their impact on surveys such as the Large Synoptic Survey Telescope. Title: The Multiple Continuum Components in the White-Light Flare of 16 January 2009 on the dM4.5e Star YZ CMi Authors: Kowalski, A. F.; Hawley, S. L.; Holtzman, J. A.; Wisniewski, J. P.; Hilton, E. J. Bibcode: 2012SoPh..277...21K Altcode: 2011arXiv1109.0837K The white light during M dwarf flares has long been known to exhibit the broadband shape of a T≈10 000 K blackbody, and the white light in solar-flares is thought to arise primarily from hydrogen recombination. Yet, a current lack of broad-wavelength coverage solar flare spectra in the optical/near-UV region prohibits a direct comparison of the continuum properties to determine if they are indeed so different. New spectroscopic observations of a secondary flare during the decay of a megaflare on the dM4.5e star YZ CMi have revealed multiple components in the white-light continuum of stellar flares, including both a blackbody-like spectrum and a hydrogen-recombination spectrum. One of the most surprising findings is that these two components are anti-correlated in their temporal evolution. We combine initial phenomenological modeling of the continuum components with spectra from radiative hydrodynamic models to show that continuum veiling causes the measured anti-correlation. This modeling allows us to use the components' inferred properties to predict how a similar spatially resolved, multiple-component, white-light continuum might appear using analogies to several solar-flare phenomena. We also compare the properties of the optical stellar flare white light to Ellerman bombs on the Sun. Title: MMT Hectochelle Spectral Variability of Active Late-type Stars in the Kepler Field (2012A) Authors: Brown, Alexander; Walkowicz, Lucianne; Hawley, Suzanne; Kowalski, Adam; Saar, Steven; Furesz, Gabor Bibcode: 2012noao.prop..332B Altcode: We have on-going Kepler photometric monitoring of over 200 active late-type (mid-A - K) stars as part of our Cycles 1/2/3 Guest Observer (GO) programs with the aim of studying starspot evolution, differential rotation, activity cycles, and flares. We propose to use the MMT Hectochelle multiobject spectrograph to observe over 120 of these stars to determine a range of basic physical properties for the stars, such as radial velocity variations due to binarity, chromospheric activity levels from Ca II H+K and H(alpha), projected rotational velocities for comparison to the rotational periods measured directly by Kepler, age/youth as indicated by Li I, and better effective temperature and luminosity estimates. In addition, to provide a superior sample for statistical studies another ~1,000 GKM dwarf stars showing either starspot modulation from the Kepler Team's data or from our on-going deep XMM X-ray survey will be observed using the unassigned fibers in each field. These measurements require the 32,000 spectral resolution provided by Hectochelle, which is hard to obtain efficiently for 13-15th magnitude stars any other way. Title: Hα Emission Variability in Active M Dwarfs Authors: Bell, Keaton J.; Hilton, Eric J.; Davenport, James R. A.; Hawley, Suzanne L.; West, Andrew A.; Rogel, Allen B. Bibcode: 2012PASP..124...14B Altcode: 2011arXiv1112.1411B We use ∼12,000 spectra of ∼3500 magnetically active M0-M9 dwarfs from the Sloan Digital Sky Survey taken at 10-15 minute intervals, together with ∼300 spectra of ∼60 M0-M8 stars obtained hourly with the Hydra multiobject spectrometer, to probe Hα variability on timescales of minutes to weeks. With multiple observations for every star examined, we are able to characterize fluctuations in Hα emission as a function of activity strength and spectral type. Stars with greater magnetic activity (as quantified by LHα/Lbol) are found to be less variable at all spectral types. We attribute this result to the stronger level of persistent emission in the high-activity stars, requiring a larger heating event in order to produce measurable variability. We also construct Hα structure functions to constrain the timescale of variability. The more active objects with lower variability exhibit a characteristic timescale longer than 1 hr, likely due to larger, longer lasting heating events, while the less active objects with higher variability have a characteristic timescale shorter than 15 minutes. Title: Probing the Flare Atmospheres of M Dwarfs Using Infrared Emission Lines Authors: Schmidt, Sarah J.; Kowalski, Adam F.; Hawley, Suzanne L.; Hilton, Eric J.; Wisniewski, John P.; Tofflemire, Benjamin M. Bibcode: 2012ApJ...745...14S Altcode: 2011arXiv1111.7072S We present the results of a campaign to monitor active M dwarfs using infrared spectroscopy, supplemented with optical photometry and spectroscopy. We detected 16 flares during nearly 50 hr of observations on EV Lac, AD Leo, YZ CMi, and VB 8. The three most energetic flares also showed infrared emission, including the first reported detections of Pβ, Pγ, He I λ10830, and Brγ during an M dwarf flare. The strongest flare (Δu = 4.02 on EV Lac) showed emission from Hγ, Hδ, He I λ4471, and Ca II K in the UV/blue and Pβ, Pγ, Pδ, Brγ, and He I λ10830 in the infrared. The weaker flares (Δu = 1.68 on EV Lac and ΔU = 1.38 on YZ CMi) were only observed with photometry and infrared spectroscopy; both showed emission from Pβ, Pγ, and He I λ10830. The strongest infrared emission line, Pβ, occurred in the active mid-M dwarfs with a duty cycle of ~3%-4%. To examine the most energetic flare, we used the static NLTE radiative transfer code RH to produce model spectra based on a suite of one-dimensional model atmospheres. Using a hotter chromosphere than previous one-dimensional atmospheric models, we obtain line ratios that match most of the observed emission lines.

Based on observations obtained with the Apache Point Observatory 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium. Title: The Implications of M Dwarf Flares on the Detection and Characterization of Exoplanets at Infrared Wavelengths Authors: Tofflemire, Benjamin M.; Wisniewski, John P.; Kowalski, Adam F.; Schmidt, Sarah J.; Kundurthy, Praveen; Hilton, Eric J.; Holtzman, Jon A.; Hawley, Suzanne L. Bibcode: 2012AJ....143...12T Altcode: 2011arXiv1111.1793T We present the results of an observational campaign which obtained high-cadence, high-precision, simultaneous optical and IR photometric observations of three M dwarf flare stars for 47 hr. The campaign was designed to characterize the behavior of energetic flare events, which routinely occur on M dwarfs, at IR wavelengths to millimagnitude precision, and quantify to what extent such events might influence current and future efforts to detect and characterize extrasolar planets surrounding these stars. We detected and characterized four highly energetic optical flares having U-band total energies of ~7.8 × 1030 to ~1.3 × 1032 erg, and found no corresponding response in the J, H, or Ks bandpasses at the precision of our data. For active dM3e stars, we find that a ~1.3 × 1032 erg U-band flare (ΔU max ~ 1.5 mag) will induce <8.3 (J), <8.5 (H), and <11.7 (Ks) mmag of a response. A flare of this energy or greater should occur less than once per 18 hr. For active dM4.5e stars, we find that a ~5.1 × 1031 erg U-band flare (ΔU max ~ 1.6 mag) will induce <7.8 (J), <8.8 (H), and <5.1 (Ks) mmag of a response. A flare of this energy or greater should occur less than once per 10 hr. No evidence of stellar variability not associated with discrete flare events was observed at the level of ~3.9 mmag over 1 hr timescales and at the level of ~5.6 mmag over 7.5 hr timescales. We therefore demonstrate that most M dwarf stellar activity and flares will not influence IR detection and characterization studies of M dwarf exoplanets above the level of ~5-11 mmag, depending on the filter and spectral type. We speculate that the most energetic megaflares on M dwarfs, which occur at rates of once per month, are likely to be easily detected in IR observations with sensitivity of tens of millimagnitudes. We also discuss how recent detections of line flux enhancements during M dwarf flares could influence IR transmission spectroscopic observations of M dwarf exoplanets. Title: Long-Term Optical and Near-Infrared Spectroscopic Monitoring of ɛ Aurigae During the 2009-11 Eclipse Authors: Barentine, John C.; Ketzeback, W. F.; Dembicky, J. M.; Huehnerhoff, J.; McMillan, R.; Saurage, G.; Sheldon, A.; Coughlin, J.; Ule, N.; Hawley, S.; Schmidt, S.; Wallerstein, G.; Leadbeater, R.; York, D. G. Bibcode: 2012AAS...21943312B Altcode: We present the results of a program to spectroscopically monitor the long-period (P ∼ 27 y) eclipsing binary ɛ Aurigae during the primary eclipse of 2009-11 with the ARC 3.5m telescope at Apache Point. Spectroscopic data from 3500-10000Å were obtained at a resolving power of R 38000 and from 0.9-2.5μm at R 3000 with a temporal cadence of approximately one week for the full duration of the eclipse. By noting the velocity centroids of certain weak metal lines (e.g., Na I D and K I 7699Å associated with the presumed optically-thick disk around the unseen secondary, we confirm a mid-eclipse epoch of HJD 2455384. The same lines indicate disk absorption with equivalent widths equal to or greater than the corresponding lines in the primary photosphere. The components of Hα and their evolution through the eclipse suggest the presence of weak ionized hydrogen, possibly distributed in a circumstellar ring or shell, and a separate, broad ionized component associated with the secondary disk in the form of a disk atmosphere or wind. Overall, our observations support the "consensus model'' of ɛ Aur, consisting of a 2 M⊙, F0 post-asymptotic giant branch primary and a dust-enshrouded, 6 M⊙ B8 dwarf. Variability of the profiles of certain lines such as Hα outside of eclipse encourages continued long-term synoptic monitoring of ɛ Aur between primary eclipses to better understand the circumstellar environment of the system. Title: White-Light Continuum Emission in M Dwarf Flares Authors: Kowalski, Adam; Hawley, S. L. Bibcode: 2012AAS...21910403K Altcode: A primary mode of radiative energy release in stellar flares is the optical and near-ultraviolet (NUV) continuum. However, radiative-hydrodynamic models of stellar flares using a solar flare paradigm and the sparse observations of solar and stellar flare continua are all seemingly in disagreement over the type(s) of emission that contribute to the optical/NUV continuum during flares. We have completed a long-term flare monitoring campaign using simultaneous low-resolution (3400-9200A) spectroscopic and broadband photometric observations to fully characterize the optical/NUV white light continuum emission on short timescales. To date, our most significant results come from observations during the decay phase of a megaflare on the dM4.5e star YZ CMi, where we have detected multiple continuum components that contribute to the white light near the Balmer jump (3646A). We present a time-resolved spectral analysis of the continuum components and emission lines for this flare and for several other large and small flares obtained during our spectroscopic monitoring campaign. We compare these data to phenomenological flare models with the RH code and to preliminary results from the next-generation of radiative-hydrodynamic 1D flare models with the RADYN code.

Funding for this project has been provided by NSF AST 0807205. Observations were obtained with the ARC 3.5m, the NMSU 1m, and the ARCSAT 0.5m at the Apache Point Observatory. Title: Kinematics, Colors, And Ages Of Ultracool Dwarfs Authors: Schmidt, Sarah J.; Hawley, S. L. Bibcode: 2012AAS...21933006S Altcode: We present results from multiple spectroscopic and photometric datasets for late-M and L dwarfs in the field. These include L dwarfs selected in SDSS data release 7, ultracool dwarfs within 20pc of the Sun as part of the Brown Dwarfs Kinematics Project, and first results from our SDSS-III ancillary program to obtain spectra of late-M and L dwarfs. Combining radial velocities, proper motions, and colors from each of these complementary datasets, we examine the ages of field L dwarfs and investigate relations between color and age. Title: Hα Variability in Active Equal-Mass M Dwarf Wide Binaries Authors: Gunning, Heather C.; Schmidt, S. J.; Davenport, J. R. A.; Hawley, S. L.; Dhital, S. Bibcode: 2012AAS...21934516G Altcode: We present monitoring of equal-mass, active mid-M dwarf wide binaries using the mid-resolution optical spectrograph on the Astrophysical Research Consortium 3.5-m telescope. We selected our sample for spectroscopic follow-up from the Sloan Low-mass Wide Pairs of Kinematically Equivalent Stars (SLoWPoKES) catalog. Our goal is to examine the differences in activity level, as measured by the equivalent width of Hα, of stars of similar masses, metallicities, and ages. We will compare both the mean and the normalized variability of Hα between the companions of each of our wide binary pairs. Additionally, we will examine the variation in molecular bands, such as the temperature-sensitive TiO feature, over time. Title: The Sloan Digital Sky Survey Data Release 7 M Dwarf Spectroscopic Catalog Authors: West, A. A.; Morgan, D. P.; Bochanski, J. J.; Andersen, J. M.; Bell, K. J.; Kowalski, A. F.; Davenport, J. R. A.; Hawley, S. L.; Schmidt, S. J.; Bernat, D.; Hilton, E. J.; Muirhead, P.; Covey, K. R.; Rojas-Ayala, B.; Schlawin, E.; Gooding, M.; Schluns, K.; Dhital, S.; Pineda, J. S.; Jones, D. O. Bibcode: 2011ASPC..448.1407W Altcode: 2010arXiv1012.3766W; 2011csss...16.1407W We present a spectroscopic catalog of 70,841 visually inspected M dwarfs from the seventh data release (DR7) of the Sloan Digital Sky Survey (SDSS). For each spectrum, we provide measurements of the spectral type, a number of molecular bandheads, and the Hα, Hβ, Hγ, Hδ and Ca II K emission lines. In addition, we calculate the metallicity-sensitive parameter ζ and 3D space motions for most of the stars in the sample. Our catalog is cross-matched to Two Micron All Sky Survey (2MASS) infrared data, and contains photometric distances for each star. Future studies will use these data to thoroughly examine magnetic activity and kinematics in late-type M dwarfs and examine the chemical and dynamical history of the local Milky Way. Title: Mining Databases for M Dwarf Variability Authors: Davenport, J. R. A.; Becker, A. C.; Hawley, S. L.; Kowalski, A. F.; Sesar, B.; Cutri, R. M. Bibcode: 2011ASPC..448..983D Altcode: 2011csss...16..983D; 2011arXiv1101.1363D Time-resolved databases with large spatial coverage are quickly becoming a standard tool for all types of astronomical studies. We report preliminary results from our search for stellar flares in the 2MASS calibration fields. A sample of 4343 M dwarfs, spatially matched between the SDSS and the 2MASS calibration fields, each with hundreds to thousands of epochs in near infrared bandpasses, is analyzed using a modified Welch-Stetson index to characterize the variability. A Monte Carlo model was used to assess the noise of the variability index. We find significnat residuals above the noise with power-law slopes of -3.37 and -4.05 for our JH and HKs distributions respectively. This is evidence for flares being observed from M dwarfs in infrared photometry. Title: M Dwarf Flares: Exoplanet Detection Implications Authors: Tofflemire, B. M.; Wisniewski, J. P.; Hilton, E. J.; Kowalski, A. F.; Kundurthy, P.; Schmidt, S. J.; Hawley, S. L.; Holtzman, J. A. Bibcode: 2011ASPC..448.1287T Altcode: 2011csss...16.1287T Low mass stars such as M dwarfs have become prime targets for exoplanet transit searches as their low luminosities and small stellar radii could enable the detection of super-Earths residing in their habitable zones. While promising transit targets, M dwarfs are also inherently variable and can exhibit up to ∼6 magnitude flux enhancements in the optical U-band. This is significantly higher than the predicted transit depths of habitable zone super-Earths (0.005 magnitude flux decrease). The behavior of flares at infrared (IR) wavelengths, particularly those likely to be used to study and characterize M dwarf exoplanets using facilities such as the James Web Space Telescope (JWST), remains largely unknown. To address these uncertainties, we are executing a coordinated, contemporaneous monitoring program of the optical and IR flux of M dwarfs known to regularly flare. A suite of telescopes located at the Kitt Peak National Observatory and the Apache Point Observatory are used for the observations. We present the initial results of this program. Title: L Dwarf Kinematics Authors: Schmidt, S. J.; West, A. A.; Hawley, S. L. Bibcode: 2011ASPC..448..333S Altcode: 2011csss...16..333S The L spectral class is composed of both stars and brown dwarfs. Because brown dwarfs cool as they age, it is not possible to assign a mass to an L dwarf based on its Teff/spectral type. Due to this degeneracy between mass, age, and spectral type, it is especially important to determine the ages of L dwarfs. Indirect estimates of age, such as a relationship between age and J-KS color have been proposed, but a better calibration is needed. Kinematics have proven to be a useful age calibrator, and will likely be instrumental in future studies of L dwarf ages. We examine the differences between the kinematics of a large, magnitude limited sample of L dwarfs from the Sloan Digital Sky Survey, and a smaller, volume-limited sample of L dwarfs within 20pc. Both samples show a kinematically hot component, suggestive of an older population of stars. Additionally, L dwarfs with bluer J-KS colors have hotter kinematics than redder L dwarfs, indicating a relationship between J-KS color and age in both samples. Title: White Light Flare Continuum Observations with ULTRACAM Authors: Kowalski, A. F.; Mathioudakis, M.; Hawley, S. L.; Hilton, E. J.; Dhillon, V. S.; Marsh, T. R.; Copperwheat, C. M. Bibcode: 2011ASPC..448.1157K Altcode: 2011arXiv1103.0822K; 2011csss...16.1157K We present sub-second, continuous-coverage photometry of three flares on the dM3.5e star, EQ Peg A, using custom continuum filters with WHT/ULTRACAM. These data provide a new view of flare continuum emission, with each flare exhibiting a very distinct light curve morphology. The spectral shape of flare emission for the two large-amplitude flares is compared with synthetic ULTRACAM measurements taken from the spectra during the large 'megaflare' event on a similar type flare star. The white light shape during the impulsive phase of the EQ Peg flares is consistent with the range of colors derived from the megaflare continuum, which is known to contain a Hydrogen recombination component and compact, blackbody-like components. Tentative evidence in the ULTRACAM photometry is found for an anti-correlation between the emission of these components. Title: Statistical Parallax Analysis of SDSS M Dwarfs Authors: Hawley, S. L.; Bochanski, J. J.; West, A. A. Bibcode: 2011ASPC..448.1359H Altcode: 2011csss...16.1359H; 2010arXiv1012.3505H We report on the analysis of ∼ 22,000 M dwarfs using a statistical parallax method. This technique employs a maximum-likelihood formulation to simultaneously solve for the absolute magnitude, velocity ellipsoid parameters and reflex solar motion of a homogeneous stellar sample, and has previously been applied to Galactic RR Lyrae and Cepheid populations and to the Palomar/Michigan State University (PMSU) survey of nearby low-mass stars. We analyze subsamples of the most recent spectroscopic catalog of M dwarfs in the Sloan Digital Sky Survey (SDSS) to determine absolute magnitudes and kinematic properties as a function of spectral type, color, chromospheric activity and metallicity. We find new, independent spectral type-absolute magnitude relations, and color-absolute magnitude relations in the SDSS filters, and compare to those found from other methods. Active stars have brighter absolute magnitudes and lower metallicity stars have fainter absolute magnitudes for stars of type M0-M4. Our kinematic analysis confirms previous results for the solar motion and velocity dispersions, with more distant stars possessing larger peculiar motions, and chromospherically active (younger) stars having smaller velocity dispersions than their inactive counterparts. We find some evidence for systematic differences in the mean U and W velocities of samples subdivided by color. Title: The Galactic M Dwarf Flare Rate Authors: Hilton, E. J.; Hawley, S. L.; Kowalski, A. F.; Holtzman, J. Bibcode: 2011ASPC..448..197H Altcode: 2011csss...16..197H M dwarfs are known to flare on timescales from minutes to hours, with flux increases of several magnitudes in the blue/near-UV. These frequent, powerful events, which are caused by magnetic reconnection, will have a strong observational signature in large, time-domain surveys. The radiation and particle fluxes from flares may also exert a significant influence on the atmospheres of orbiting planets, and affect their habitability. We present a statistical model of flaring M dwarfs in the Galaxy that allows us to predict the observed flare rate along a given line of sight for a particular survey depth and cadence. The parameters that enter the model are the Galactic structure, the distribution of magnetically active and inactive M dwarfs, and the flare frequency distribution (FFD) of both populations. The FFD is a function of spectral type, activity, and Galactic height. Although inactive M dwarfs make up the majority of stars in a magnitude-limited survey, the FFD of inactive stars is very poorly constrained. We have organized a flare monitoring campaign comprising hundreds of hours of new observations from both the ground and space to better constrain flare rates. Incorporating the new observations into our model provides more accurate predictions of stellar variability caused by flares on M dwarfs. We pay particular attention to the likelihood of flares appearing as optical transients (i.e., host star not seen in quiescent data). Title: Splinter Session "Solar and Stellar Flares" Authors: Fletcher, L.; Hudson, H.; Cauzzi, G.; Getman, K. V.; Giampapa, M.; Hawley, S. L.; Heinzel, P.; Johnstone, C.; Kowalski, A. F.; Osten, R. A.; Pye, J. Bibcode: 2011ASPC..448..441F Altcode: 2011csss...16..441F; 2012arXiv1206.3997F This summary reports on papers presented at the Cool Stars-16 meeting in the splinter session "Solar and Stellar flares." Although many topics were discussed, the main themes were the commonality of interests, and of physics, between the solar and stellar flare communities, and the opportunities for important new observations in the near future. Title: SDSS-III: Massive Spectroscopic Surveys of the Distant Universe, the Milky Way, and Extra-Solar Planetary Systems Authors: Eisenstein, Daniel J.; Weinberg, David H.; Agol, Eric; Aihara, Hiroaki; Allende Prieto, Carlos; Anderson, Scott F.; Arns, James A.; Aubourg, Éric; Bailey, Stephen; Balbinot, Eduardo; Barkhouser, Robert; Beers, Timothy C.; Berlind, Andreas A.; Bickerton, Steven J.; Bizyaev, Dmitry; Blanton, Michael R.; Bochanski, John J.; Bolton, Adam S.; Bosman, Casey T.; Bovy, Jo; Brandt, W. N.; Breslauer, Ben; Brewington, Howard J.; Brinkmann, J.; Brown, Peter J.; Brownstein, Joel R.; Burger, Dan; Busca, Nicolas G.; Campbell, Heather; Cargile, Phillip A.; Carithers, William C.; Carlberg, Joleen K.; Carr, Michael A.; Chang, Liang; Chen, Yanmei; Chiappini, Cristina; Comparat, Johan; Connolly, Natalia; Cortes, Marina; Croft, Rupert A. C.; Cunha, Katia; da Costa, Luiz N.; Davenport, James R. A.; Dawson, Kyle; De Lee, Nathan; Porto de Mello, Gustavo F.; de Simoni, Fernando; Dean, Janice; Dhital, Saurav; Ealet, Anne; Ebelke, Garrett L.; Edmondson, Edward M.; Eiting, Jacob M.; Escoffier, Stephanie; Esposito, Massimiliano; Evans, Michael L.; Fan, Xiaohui; Femenía Castellá, Bruno; Dutra Ferreira, Leticia; Fitzgerald, Greg; Fleming, Scott W.; Font-Ribera, Andreu; Ford, Eric B.; Frinchaboy, Peter M.; García Pérez, Ana Elia; Gaudi, B. Scott; Ge, Jian; Ghezzi, Luan; Gillespie, Bruce A.; Gilmore, G.; Girardi, Léo; Gott, J. Richard; Gould, Andrew; Grebel, Eva K.; Gunn, James E.; Hamilton, Jean-Christophe; Harding, Paul; Harris, David W.; Hawley, Suzanne L.; Hearty, Frederick R.; Hennawi, Joseph F.; González Hernández, Jonay I.; Ho, Shirley; Hogg, David W.; Holtzman, Jon A.; Honscheid, Klaus; Inada, Naohisa; Ivans, Inese I.; Jiang, Linhua; Jiang, Peng; Johnson, Jennifer A.; Jordan, Cathy; Jordan, Wendell P.; Kauffmann, Guinevere; Kazin, Eyal; Kirkby, David; Klaene, Mark A.; Knapp, G. R.; Kneib, Jean-Paul; Kochanek, C. S.; Koesterke, Lars; Kollmeier, Juna A.; Kron, Richard G.; Lampeitl, Hubert; Lang, Dustin; Lawler, James E.; Le Goff, Jean-Marc; Lee, Brian L.; Lee, Young Sun; Leisenring, Jarron M.; Lin, Yen-Ting; Liu, Jian; Long, Daniel C.; Loomis, Craig P.; Lucatello, Sara; Lundgren, Britt; Lupton, Robert H.; Ma, Bo; Ma, Zhibo; MacDonald, Nicholas; Mack, Claude; Mahadevan, Suvrath; Maia, Marcio A. G.; Majewski, Steven R.; Makler, Martin; Malanushenko, Elena; Malanushenko, Viktor; Mandelbaum, Rachel; Maraston, Claudia; Margala, Daniel; Maseman, Paul; Masters, Karen L.; McBride, Cameron K.; McDonald, Patrick; McGreer, Ian D.; McMahon, Richard G.; Mena Requejo, Olga; Ménard, Brice; Miralda-Escudé, Jordi; Morrison, Heather L.; Mullally, Fergal; Muna, Demitri; Murayama, Hitoshi; Myers, Adam D.; Naugle, Tracy; Neto, Angelo Fausti; Nguyen, Duy Cuong; Nichol, Robert C.; Nidever, David L.; O'Connell, Robert W.; Ogando, Ricardo L. C.; Olmstead, Matthew D.; Oravetz, Daniel J.; Padmanabhan, Nikhil; Paegert, Martin; Palanque-Delabrouille, Nathalie; Pan, Kaike; Pandey, Parul; Parejko, John K.; Pâris, Isabelle; Pellegrini, Paulo; Pepper, Joshua; Percival, Will J.; Petitjean, Patrick; Pfaffenberger, Robert; Pforr, Janine; Phleps, Stefanie; Pichon, Christophe; Pieri, Matthew M.; Prada, Francisco; Price-Whelan, Adrian M.; Raddick, M. Jordan; Ramos, Beatriz H. F.; Reid, I. Neill; Reyle, Celine; Rich, James; Richards, Gordon T.; Rieke, George H.; Rieke, Marcia J.; Rix, Hans-Walter; Robin, Annie C.; Rocha-Pinto, Helio J.; Rockosi, Constance M.; Roe, Natalie A.; Rollinde, Emmanuel; Ross, Ashley J.; Ross, Nicholas P.; Rossetto, Bruno; Sánchez, Ariel G.; Santiago, Basilio; Sayres, Conor; Schiavon, Ricardo; Schlegel, David J.; Schlesinger, Katharine J.; Schmidt, Sarah J.; Schneider, Donald P.; Sellgren, Kris; Shelden, Alaina; Sheldon, Erin; Shetrone, Matthew; Shu, Yiping; Silverman, John D.; Simmerer, Jennifer; Simmons, Audrey E.; Sivarani, Thirupathi; Skrutskie, M. F.; Slosar, Anže; Smee, Stephen; Smith, Verne V.; Snedden, Stephanie A.; Stassun, Keivan G.; Steele, Oliver; Steinmetz, Matthias; Stockett, Mark H.; Stollberg, Todd; Strauss, Michael A.; Szalay, Alexander S.; Tanaka, Masayuki; Thakar, Aniruddha R.; Thomas, Daniel; Tinker, Jeremy L.; Tofflemire, Benjamin M.; Tojeiro, Rita; Tremonti, Christy A.; Vargas Magaña, Mariana; Verde, Licia; Vogt, Nicole P.; Wake, David A.; Wan, Xiaoke; Wang, Ji; Weaver, Benjamin A.; White, Martin; White, Simon D. M.; Wilson, John C.; Wisniewski, John P.; Wood-Vasey, W. Michael; Yanny, Brian; Yasuda, Naoki; Yèche, Christophe; York, Donald G.; Young, Erick; Zasowski, Gail; Zehavi, Idit; Zhao, Bo Bibcode: 2011AJ....142...72E Altcode: 2011arXiv1101.1529E Building on the legacy of the Sloan Digital Sky Survey (SDSS-I and II), SDSS-III is a program of four spectroscopic surveys on three scientific themes: dark energy and cosmological parameters, the history and structure of the Milky Way, and the population of giant planets around other stars. In keeping with SDSS tradition, SDSS-III will provide regular public releases of all its data, beginning with SDSS Data Release 8 (DR8), which was made public in 2011 January and includes SDSS-I and SDSS-II images and spectra reprocessed with the latest pipelines and calibrations produced for the SDSS-III investigations. This paper presents an overview of the four surveys that comprise SDSS-III. The Baryon Oscillation Spectroscopic Survey will measure redshifts of 1.5 million massive galaxies and Lyα forest spectra of 150,000 quasars, using the baryon acoustic oscillation feature of large-scale structure to obtain percent-level determinations of the distance scale and Hubble expansion rate at z < 0.7 and at z ≈ 2.5. SEGUE-2, an already completed SDSS-III survey that is the continuation of the SDSS-II Sloan Extension for Galactic Understanding and Exploration (SEGUE), measured medium-resolution (R = λ/Δλ ≈ 1800) optical spectra of 118,000 stars in a variety of target categories, probing chemical evolution, stellar kinematics and substructure, and the mass profile of the dark matter halo from the solar neighborhood to distances of 100 kpc. APOGEE, the Apache Point Observatory Galactic Evolution Experiment, will obtain high-resolution (R ≈ 30,000), high signal-to-noise ratio (S/N >= 100 per resolution element), H-band (1.51 μm < λ < 1.70 μm) spectra of 105 evolved, late-type stars, measuring separate abundances for ~15 elements per star and creating the first high-precision spectroscopic survey of all Galactic stellar populations (bulge, bar, disks, halo) with a uniform set of stellar tracers and spectral diagnostics. The Multi-object APO Radial Velocity Exoplanet Large-area Survey (MARVELS) will monitor radial velocities of more than 8000 FGK stars with the sensitivity and cadence (10-40 m s-1, ~24 visits per star) needed to detect giant planets with periods up to two years, providing an unprecedented data set for understanding the formation and dynamical evolution of giant planet systems. As of 2011 January, SDSS-III has obtained spectra of more than 240,000 galaxies, 29,000 z >= 2.2 quasars, and 140,000 stars, including 74,000 velocity measurements of 2580 stars for MARVELS. Title: Erratum: "The Eighth Data Release of the Sloan Digital Sky Survey: First Data from SDSS-III" (2011, ApJS, 193, 29) Authors: Aihara, Hiroaki; Allende Prieto, Carlos; An, Deokkeun; Anderson, Scott F.; Aubourg, Éric; Balbinot, Eduardo; Beers, Timothy C.; Berlind, Andreas A.; Bickerton, Steven J.; Bizyaev, Dmitry; Blanton, Michael R.; Bochanski, John J.; Bolton, Adam S.; Bovy, Jo; Brandt, W. N.; Brinkmann, J.; Brown, Peter J.; Brownstein, Joel R.; Busca, Nicolas G.; Campbell, Heather; Carr, Michael A.; Chen, Yanmei; Chiappini, Cristina; Comparat, Johan; Connolly, Natalia; Cortes, Marina; Croft, Rupert A. C.; Cuesta, Antonio J.; da Costa, Luiz N.; Davenport, James R. A.; Dawson, Kyle; Dhital, Saurav; Ealet, Anne; Ebelke, Garrett L.; Edmondson, Edward M.; Eisenstein, Daniel J.; Escoffier, Stephanie; Esposito, Massimiliano; Evans, Michael L.; Fan, Xiaohui; Femenía Castellá, Bruno; Font-Ribera, Andreu; Frinchaboy, Peter M.; Ge, Jian; Gillespie, Bruce A.; Gilmore, G.; González Hernández, Jonay I.; Gott, J. Richard; Gould, Andrew; Grebel, Eva K.; Gunn, James E.; Hamilton, Jean-Christophe; Harding, Paul; Harris, David W.; Hawley, Suzanne L.; Hearty, Frederick R.; Ho, Shirley; Hogg, David W.; Holtzman, Jon A.; Honscheid, Klaus; Inada, Naohisa; Ivans, Inese I.; Jiang, Linhua; Johnson, Jennifer A.; Jordan, Cathy; Jordan, Wendell P.; Kazin, Eyal A.; Kirkby, David; Klaene, Mark A.; Knapp, G. R.; Kneib, Jean-Paul; Kochanek, C. S.; Koesterke, Lars; Kollmeier, Juna A.; Kron, Richard G.; Lampeitl, Hubert; Lang, Dustin; Le Goff, Jean-Marc; Lee, Young Sun; Lin, Yen-Ting; Long, Daniel C.; Loomis, Craig P.; Lucatello, Sara; Lundgren, Britt; Lupton, Robert H.; Ma, Zhibo; MacDonald, Nicholas; Mahadevan, Suvrath; Maia, Marcio A. G.; Makler, Martin; Malanushenko, Elena; Malanushenko, Viktor; Mandelbaum, Rachel; Maraston, Claudia; Margala, Daniel; Masters, Karen L.; McBride, Cameron K.; McGehee, Peregrine M.; McGreer, Ian D.; Ménard, Brice; Miralda-Escudé, Jordi; Morrison, Heather L.; Mullally, F.; Muna, Demitri; Munn, Jeffrey A.; Murayama, Hitoshi; Myers, Adam D.; Naugle, Tracy; Neto, Angelo Fausti; Nguyen, Duy Cuong; Nichol, Robert C.; O'Connell, Robert W.; Ogando, Ricardo L. C.; Olmstead, Matthew D.; Oravetz, Daniel J.; Padmanabhan, Nikhil; Palanque-Delabrouille, Nathalie; Pan, Kaike; Pandey, Parul; Pâris, Isabelle; Percival, Will J.; Petitjean, Patrick; Pfaffenberger, Robert; Pforr, Janine; Phleps, Stefanie; Pichon, Christophe; Pieri, Matthew M.; Prada, Francisco; Price-Whelan, Adrian M.; Raddick, M. Jordan; Ramos, Beatriz H. F.; Reylé, Céline; Rich, James; Richards, Gordon T.; Rix, Hans-Walter; Robin, Annie C.; Rocha-Pinto, Helio J.; Rockosi, Constance M.; Roe, Natalie A.; Rollinde, Emmanuel; Ross, Ashley J.; Ross, Nicholas P.; Rossetto, Bruno M.; Sánchez, Ariel G.; Sayres, Conor; Schlegel, David J.; Schlesinger, Katharine J.; Schmidt, Sarah J.; Schneider, Donald P.; Sheldon, Erin; Shu, Yiping; Simmerer, Jennifer; Simmons, Audrey E.; Sivarani, Thirupathi; Snedden, Stephanie A.; Sobeck, Jennifer S.; Steinmetz, Matthias; Strauss, Michael A.; Szalay, Alexander S.; Tanaka, Masayuki; Thakar, Aniruddha R.; Thomas, Daniel; Tinker, Jeremy L.; Tofflemire, Benjamin M.; Tojeiro, Rita; Tremonti, Christy A.; Vandenberg, Jan; Vargas Magaña, M.; Verde, Licia; Vogt, Nicole P.; Wake, David A.; Wang, Ji; Weaver, Benjamin A.; Weinberg, David H.; White, Martin; White, Simon D. M.; Yanny, Brian; Yasuda, Naoki; Yeche, Christophe; Zehavi, Idit Bibcode: 2011ApJS..195...26A Altcode: No abstract at ADS Title: An ``A star'' on an M star during a flare within a flare Authors: Kowalski, Adam F.; Hawley, Suzanne L.; Holtzman, Jon A.; Wisniewski, John P.; Hilton, Eric J. Bibcode: 2011IAUS..273..261K Altcode: 2010arXiv1010.0452K M dwarfs produce explosive flare emission in the near-UV and optical continuum, and the mechanism responsible for this phenomenon is not well-understood. We present a near-UV/optical flare spectrum from the rise phase of a secondary flare, which occurred during the decay of a much larger flare. The newly formed flare emission resembles the spectrum of an early-type star, with the Balmer lines and continuum in absorption. We model this observation phenomenologically as a temperature bump (hot spot) near the photosphere of the M dwarf. The amount of heating implied by our model (ΔTphot ~ 16,000 K) is far more than predicted by chromospheric backwarming in current 1D RHD flare models (ΔTphot ~ 1200 K). Title: Starspot variability and evolution from modeling Kepler photometry of active late-type stars Authors: Brown, Alexander; Korhonen, Heidi; Berdyugina, Svetlana; Tofany, Barton; Ayres, Thomas R.; Kowalski, Adam; Hawley, Suzanne; Harper, Graham; Piskunov, Nikolai Bibcode: 2011IAUS..273...78B Altcode: The Kepler satellite provides a unique opportunity to study the detailed optical photometric variability of late-type stars with unprecedentedly long (several year) continuous monitoring and sensitivity to very small-scale variations. We are studying a sample of over two hundred cool (mid-A - late-K spectral type) stars using Kepler long-cadence (30 minute sampling) observations. These stars show a remarkable range of photometric variability, but in this paper we concentrate on rotational modulation due to starspots and flaring. Modulation at the 0.1% level is readily discernable. We highlight the rapid timescales of starspot evolution seen on solar-like stars with rotational periods between 2 and 7 days. Title: The First Detection of Time-Variable Infrared Line Emission During M Dwarf Flares Authors: Schmidt, Sarah J.; Hilton, E. J.; Tofflemire, B.; Wisniewski, J. P.; Kowalski, A. F.; Holtzman, J.; Hawley, S. L. Bibcode: 2011AAS...21832604S Altcode: 2011BAAS..43G32604S M dwarfs are notorious for their active chromospheres, characterized by quiescent line emission at optical wavelengths in addition to dramatic flare events. These flares have been well-studied at X-ray, radio, UV, and optical wavelengths, but so far there is only one single-epoch detection of high-order Paschen emission lines in a red optical spectrum (Schmidt et al. 2007). In order to investigate infrared line emission during flares, we have conducted a monitoring campaign totaling about 60 hours on 5 active M dwarfs. We have obtained infrared (0.9 to 2.4 micron) spectroscopy using the TripleSpec instrument on the Apache Point Observatory 3.5-m, simultaneous optical/UV photometry on the NMSU 1-m and ARC 0.8-m, and optical spectroscopy on the DAO 1.8-m for one run. During the three brightest flares observed on EV Lac and YZ CMi (> 2 magnitudes in U), we observed emission from Hydrogen Paschen beta, gamma, and delta; Brackett gamma, and Helium 10830A. We characterize the strength and time variation of these lines and investigate the heating needed to produce infrared emission during flares. Title: Light Curves, Energetics and Rates of M Dwarf Flares Authors: Hilton, Eric J.; Hawley, S. L.; Kowalski, A. F.; Schmidt, S. J.; Davenport, J. R. A.; Wisniewski, J. P.; Bell, K. J.; Tofflemire, B.; Holtzman, J. Bibcode: 2011AAS...21832502H Altcode: 2011BAAS..43G32502H The magnetic reconnection events that power stellar flares lead to a wide variety of light curve shapes, hinting at the complex underlying magnetic field topologies. Using our quantitative definition of a flare event, we find more than 100 flares during 600 hours of photometric monitoring of two dozen stars. The sample includes both active and inactive M dwarfs with a range of spectral type. We fit models for the light curve evolution to our photometric flare catalogue and present an analysis of the rise and decay times as well as flare colors. We additionally present the distribution of flare rates as a function of energy and equivalent duration. The flare frequency distribution is used to characterize the impact of M dwarf flares seen in time domain surveys, and is also necessary to model the effect of flares on the atmospheres of exoplanets orbiting an M dwarf host. Title: High Cadence Kepler Observations of Flare Stars Authors: Hawley, Suzanne L.; Kowalski, A. F.; Wisniewski, J. P.; Hilton, E. J.; Walkowicz, L. M.; Brown, A. Bibcode: 2011AAS...21822705H Altcode: 2011BAAS..43G22705H We report on preliminary results from our Kepler Cycle 2 GO program to observe low mass stars at high cadence (one observation per minute). The outstanding fidelity of the Kepler light curves reveals both starspot modulation and a large number of stellar flares. We investigate the flare amplitude, frequency and energy distributions and relate these to the better-known nearby flare stars in the solar neighborhood. Title: Hα Variability in Active M Dwarf Spectra on Intermediate Timescales Authors: Bell, Keaton; Hilton, E. J.; Hawley, S. L.; Rogel, A. B. Bibcode: 2011AAS...21832605B Altcode: 2011BAAS..43G32605B The strength of Hα emission in magnetically active M dwarfs has been observed to increase on very short (seconds) timescales during flares, and to decrease on very long (millions-billions of years) timescales with stellar aging. We utilize a set of 13,000 time-resolved active M dwarf spectra taken on several-minute intervals from the Sloan Digital Sky Survey and an independent set of 312 Hydra spectra taken hourly with the WIYN 3.5-meter telescope to study Hα variability on intermediate timescales. With several observations per target, and with many targets observed on multiple nights, we are able to probe variability in the equivalent width measurements of Hα on timescales from minutes to weeks. We will present the variability structure function and discuss it in the context of previous results. Title: UV Diagnostics of Stellar and Solar Flares Authors: Kowalski, Adam; Hawley, S. L.; Hudson, H. S. Bibcode: 2011AAS...21821303K Altcode: 2011BAAS..43G21303K The UV spectral regime provides a comprehensive view of the plasma dynamics and atmospheric temperature structure during stellar flares. We review the major developments in UV spectroscopy of flares on low mass stars that shape our understanding of the flare process and challenge the predictions of current radiative hydrodynamic models. We put the ultraviolet properties in context with the radiation in the neighboring X-ray and visible wavelength regimes. We also show how SDO/EVE data of several Cycle 24 solar flares allow for new comparisons to be made between solar and stellar flares. Title: M Dwarf Photometric Variability In The Optical And NIR Authors: Davenport, James R. A.; Becker, A. C.; Kowalski, A. F.; Hawley, S. L.; Hilton, E. J. Bibcode: 2011AAS...21832603D Altcode: 2011BAAS..43G32603D We present limits on the observability of stochastic flare events from M dwarfs in SDSS and 2MASS filters. We have studied 30,000 M dwarfs from the SDSS Stripe 82 time-domain catalog, and 4300 M dwarfs from the 2MASS Calibration Scan Point Source Working Database which overlap the SDSS DR7 single-epoch data. M dwarfs are chosen based on their SDSS r,i,z colors. Stripe 82 stars each have 50-100 epochs of data, while 2MASS Calibration stars have 2000-3000. An M dwarf continuum spectral model is used to predict observed flare signatures in each band. From these data we estimate the observed rates and theoretical detection thresholds for flares in eight photometric bands as a function of spectral type. The structure function of the variability for each spectral type bin is also calculated for all eight bands. These rates of flares and photometric variations at longer wavelengths will be important for predicting the impact of M dwarf variability in next-generation instruments such as JWST. Title: Kepler Observations of Starspot Evolution, Differential Rotation, and Flares on Late-Type Stars Authors: Brown, Alexander; Korhonen, H.; Berdyugina, S.; Walkowicz, L.; Kowalski, A.; Hawley, S.; Neff, J.; Ramsey, L.; Redman, S.; Saar, S.; Furesz, G.; Piskunov, N.; Harper, G.; Ayres, T.; Tofany, B. Bibcode: 2011AAS...21820502B Altcode: 2011BAAS..43G20502B The Kepler satellite is providing spectacular optical photometric light-curves of unprecedented precision and duration that routinely allow detailed studies of stellar magnetic activity on late-type stars that were difficult, if not impossible, to attempt previously. Rotational modulation due to starspots is commonly seen in the Kepler light-curves of late-type stars, allowing detailed study of the surface distribution of their photospheric magnetic activity. Kepler is providing multi-year duration light-curves that allow us to investigate how activity phenomena -- such as the growth, migration, and decay of starspots, differential rotation, activity cycles, and flaring -- operate on single and binary stars with a wide range of mass and convection zone depth.

We present the first results from detailed starspot modeling using newly-developed light-curve inversion codes for a range of GALEX-selected stars with typical rotation periods of a few days, that we have observed as part of our 200 target Kepler Cycle 1/2 Guest Observer programs. The physical properties of the stars have been measured using high resolution optical spectroscopy, which allows the Kepler results to be placed within the existing framework of knowledge regarding stellar magnetic activity. These results demonstrate the powerful diagnostic capability provided by tracking starspot evolution essentially continuously for more than 16 months. The starspots are clearly sampling the stellar rotation rate at different latitudes, enabling us to measure the differential rotation and starspot lifetimes. As would be expected, stars with few day rotation show frequent flaring that is easily seen as "white-light" flares in Kepler light-curves. We compare the observed flare rates and occurrence with the starspot properties.

This work contains results obtained using the NASA Kepler satellite and from the Apache Point Observatory, the MMT (using NOAO community access time), and the Hobby-Eberly Telescope. Funding is provided by NASA Kepler grants NNX10AC51G and NNX11AC79G. Title: Kepler Observations of Pulsations In A Sample of Magnetically-Active Stars Authors: Neff, James E.; Brown, A.; Hawley, S.; Kowalski, A.; Walkowicz, L.; Saar, S. Bibcode: 2011AAS...21822704N Altcode: 2011BAAS..43G22704N We have observed about 200 targets in Kepler Cycle 1/2 Guest Observer programs. The sample of active star candidates was selected primarily using GALEX colors, and the Kepler light curves have revealed a rich variety of variability. Rotational modulation (typical periods a few days) due to starspots over the multi-year timeline of the Kepler observations will permit us to measure surface differential rotation and stellar magnetic cycles. On shorter timescales, the Kepler data show dramatic evidence of stellar pulsations across much of the HR diagram. Our selection criteria yielded a sample of magnetically active G and K dwarfs, which might show solar-like pulsations. It also yielded subsamples of several well-known pulsators (e.g., Delta Scuti stars) as well as pulsators that currently defy easy classification. We are systematically classifying and analyzing the pulsating stars in the our Kepler GO program. We are particularly interested in using pulsations to probe the interior properties of active G and K dwarfs, while the starspots serve as a probe of the convection zone and surface layers. We will present summary results for several different types of pulsation, and we will provide a detailed asteroseismic analysis of those stars in our sample that were observed to have both pulsations and magnetic activity.

This work contains results obtained using the NASA Kepler satellite and from the Apache Point Observatory, the MMT (using NOAO community access time), and the Hobby-Eberly Telescope. Funding is provided by NASA Kepler grants NNX10AC51G and NNX11AC79G. Title: Periodic Variability of Low-mass Stars in Sloan Digital Sky Survey Stripe 82 Authors: Becker, A. C.; Bochanski, J. J.; Hawley, S. L.; Ivezić, Ž.; Kowalski, A. F.; Sesar, B.; West, A. A. Bibcode: 2011ApJ...731...17B Altcode: 2011arXiv1102.1387B We present a catalog of periodic stellar variability in the "Stripe 82" region of the Sloan Digital Sky Survey. After aggregating and re-calibrating catalog-level data from the survey, we ran a period-finding algorithm (Supersmoother) on all point-source light curves. We used color selection to identify systems that are likely to contain low-mass stars, in particular M dwarfs and white dwarfs. In total, we found 207 candidates, the vast majority of which appear to be in eclipsing binary systems. The catalog described in this paper includes 42 candidate M dwarf/white dwarf pairs, four white dwarf pairs, 59 systems whose colors indicate they are composed of two M dwarfs and whose light-curve shapes suggest they are in detached eclipsing binaries, and 28 M dwarf systems whose light-curve shapes suggest they are in contact binaries. We find no detached systems with periods longer than 3 days, thus the majority of our sources are likely to have experienced orbital spin-up and enhanced magnetic activity. Indeed, 26 of 27 M dwarf systems that we have spectra for show signs of chromospheric magnetic activity, far higher than the 24% seen in field stars of the same spectral type. We also find binaries composed of stars that bracket the expected boundary between partially and fully convective interiors, which will allow the measurement of the stellar mass-radius relationship across this transition. The majority of our contact systems have short orbital periods, with small variance (0.02 days) in the sample near the observed cutoff of 0.22 days. The accumulation of these stars at short orbital period suggests that the process of angular momentum loss, leading to period evolution, becomes less efficient at short periods. These short-period systems are in a novel regime for studying the effects of orbital spin-up and enhanced magnetic activity, which are thought to be the source of discrepancies between mass-radius predictions and measurements of these properties in eclipsing binaries. Title: The Eighth Data Release of the Sloan Digital Sky Survey: First Data from SDSS-III Authors: Aihara, Hiroaki; Allende Prieto, Carlos; An, Deokkeun; Anderson, Scott F.; Aubourg, Éric; Balbinot, Eduardo; Beers, Timothy C.; Berlind, Andreas A.; Bickerton, Steven J.; Bizyaev, Dmitry; Blanton, Michael R.; Bochanski, John J.; Bolton, Adam S.; Bovy, Jo; Brandt, W. N.; Brinkmann, J.; Brown, Peter J.; Brownstein, Joel R.; Busca, Nicolas G.; Campbell, Heather; Carr, Michael A.; Chen, Yanmei; Chiappini, Cristina; Comparat, Johan; Connolly, Natalia; Cortes, Marina; Croft, Rupert A. C.; Cuesta, Antonio J.; da Costa, Luiz N.; Davenport, James R. A.; Dawson, Kyle; Dhital, Saurav; Ealet, Anne; Ebelke, Garrett L.; Edmondson, Edward M.; Eisenstein, Daniel J.; Escoffier, Stephanie; Esposito, Massimiliano; Evans, Michael L.; Fan, Xiaohui; Femenía Castellá, Bruno; Font-Ribera, Andreu; Frinchaboy, Peter M.; Ge, Jian; Gillespie, Bruce A.; Gilmore, G.; González Hernández, Jonay I.; Gott, J. Richard; Gould, Andrew; Grebel, Eva K.; Gunn, James E.; Hamilton, Jean-Christophe; Harding, Paul; Harris, David W.; Hawley, Suzanne L.; Hearty, Frederick R.; Ho, Shirley; Hogg, David W.; Holtzman, Jon A.; Honscheid, Klaus; Inada, Naohisa; Ivans, Inese I.; Jiang, Linhua; Johnson, Jennifer A.; Jordan, Cathy; Jordan, Wendell P.; Kazin, Eyal A.; Kirkby, David; Klaene, Mark A.; Knapp, G. R.; Kneib, Jean-Paul; Kochanek, C. S.; Koesterke, Lars; Kollmeier, Juna A.; Kron, Richard G.; Lampeitl, Hubert; Lang, Dustin; Le Goff, Jean-Marc; Lee, Young Sun; Lin, Yen-Ting; Long, Daniel C.; Loomis, Craig P.; Lucatello, Sara; Lundgren, Britt; Lupton, Robert H.; Ma, Zhibo; MacDonald, Nicholas; Mahadevan, Suvrath; Maia, Marcio A. G.; Makler, Martin; Malanushenko, Elena; Malanushenko, Viktor; Mandelbaum, Rachel; Maraston, Claudia; Margala, Daniel; Masters, Karen L.; McBride, Cameron K.; McGehee, Peregrine M.; McGreer, Ian D.; Ménard, Brice; Miralda-Escudé, Jordi; Morrison, Heather L.; Mullally, F.; Muna, Demitri; Munn, Jeffrey A.; Murayama, Hitoshi; Myers, Adam D.; Naugle, Tracy; Neto, Angelo Fausti; Nguyen, Duy Cuong; Nichol, Robert C.; O'Connell, Robert W.; Ogando, Ricardo L. C.; Olmstead, Matthew D.; Oravetz, Daniel J.; Padmanabhan, Nikhil; Palanque-Delabrouille, Nathalie; Pan, Kaike; Pandey, Parul; Pâris, Isabelle; Percival, Will J.; Petitjean, Patrick; Pfaffenberger, Robert; Pforr, Janine; Phleps, Stefanie; Pichon, Christophe; Pieri, Matthew M.; Prada, Francisco; Price-Whelan, Adrian M.; Raddick, M. Jordan; Ramos, Beatriz H. F.; Reylé, Céline; Rich, James; Richards, Gordon T.; Rix, Hans-Walter; Robin, Annie C.; Rocha-Pinto, Helio J.; Rockosi, Constance M.; Roe, Natalie A.; Rollinde, Emmanuel; Ross, Ashley J.; Ross, Nicholas P.; Rossetto, Bruno M.; Sánchez, Ariel G.; Sayres, Conor; Schlegel, David J.; Schlesinger, Katharine J.; Schmidt, Sarah J.; Schneider, Donald P.; Sheldon, Erin; Shu, Yiping; Simmerer, Jennifer; Simmons, Audrey E.; Sivarani, Thirupathi; Snedden, Stephanie A.; Sobeck, Jennifer S.; Steinmetz, Matthias; Strauss, Michael A.; Szalay, Alexander S.; Tanaka, Masayuki; Thakar, Aniruddha R.; Thomas, Daniel; Tinker, Jeremy L.; Tofflemire, Benjamin M.; Tojeiro, Rita; Tremonti, Christy A.; Vandenberg, Jan; Vargas Magaña, M.; Verde, Licia; Vogt, Nicole P.; Wake, David A.; Wang, Ji; Weaver, Benjamin A.; Weinberg, David H.; White, Martin; White, Simon D. M.; Yanny, Brian; Yasuda, Naoki; Yeche, Christophe; Zehavi, Idit Bibcode: 2011ApJS..193...29A Altcode: 2011arXiv1101.1559S The Sloan Digital Sky Survey (SDSS) started a new phase in 2008 August, with new instrumentation and new surveys focused on Galactic structure and chemical evolution, measurements of the baryon oscillation feature in the clustering of galaxies and the quasar Lyα forest, and a radial velocity search for planets around ~8000 stars. This paper describes the first data release of SDSS-III (and the eighth counting from the beginning of the SDSS). The release includes five-band imaging of roughly 5200 deg2 in the southern Galactic cap, bringing the total footprint of the SDSS imaging to 14,555 deg2, or over a third of the Celestial Sphere. All the imaging data have been reprocessed with an improved sky-subtraction algorithm and a final, self-consistent photometric recalibration and flat-field determination. This release also includes all data from the second phase of the Sloan Extension for Galactic Understanding and Exploration (SEGUE-2), consisting of spectroscopy of approximately 118,000 stars at both high and low Galactic latitudes. All the more than half a million stellar spectra obtained with the SDSS spectrograph have been reprocessed through an improved stellar parameter pipeline, which has better determination of metallicity for high-metallicity stars. Title: The Sloan Digital Sky Survey Data Release 7 Spectroscopic M Dwarf Catalog. II. Statistical Parallax Analysis Authors: Bochanski, John J.; Hawley, Suzanne L.; West, Andrew A. Bibcode: 2011AJ....141...98B Altcode: 2011arXiv1101.3549B We present a statistical parallax analysis of low-mass dwarfs from the Sloan Digital Sky Survey. We calculate absolute r-band magnitudes (Mr ) as a function of color and spectral type and investigate changes in Mr with location in the Milky Way. We find that magnetically active M dwarfs are intrinsically brighter in Mr than their inactive counterparts at the same color or spectral type. Metallicity, as traced by the proxy ζ, also affects Mr , with metal-poor stars having fainter absolute magnitudes than higher metallicity M dwarfs at the same color or spectral type. Additionally, we measure the velocity ellipsoid and solar reflex motion for each subsample of M dwarfs. We find good agreement between our measured solar peculiar motion and previous results for similar populations, as well as some evidence for differing motions of early and late M-type populations in U and W velocities that cannot be attributed to asymmetric drift. The reflex solar motion and the velocity dispersions both show that younger populations, as traced by magnetic activity and location near the Galactic plane, have experienced less dynamical heating. We introduce a new parameter, the independent position altitude (IPA), to investigate populations as a function of vertical height from the Galactic plane. M dwarfs at all types exhibit an increase in velocity dispersion when analyzed in comparable IPA subgroups. Title: The Sloan Digital Sky Survey Data Release 7 Spectroscopic M Dwarf Catalog. I. Data Authors: West, Andrew A.; Morgan, Dylan P.; Bochanski, John J.; Andersen, Jan Marie; Bell, Keaton J.; Kowalski, Adam F.; Davenport, James R. A.; Hawley, Suzanne L.; Schmidt, Sarah J.; Bernat, David; Hilton, Eric J.; Muirhead, Philip; Covey, Kevin R.; Rojas-Ayala, Bárbara; Schlawin, Everett; Gooding, Mary; Schluns, Kyle; Dhital, Saurav; Pineda, J. Sebastian; Jones, David O. Bibcode: 2011AJ....141...97W Altcode: 2011arXiv1101.1082W We present a spectroscopic catalog of 70,841 visually inspected M dwarfs from the seventh data release of the Sloan Digital Sky Survey. For each spectrum, we provide measurements of the spectral type, a number of molecular band heads, and the Hα, Hβ, Hγ, Hδ, and Ca II K emission lines. In addition, we calculate the metallicity-sensitive parameter ζ and identify a relationship between ζ and the g - r and r - z colors of M dwarfs. We assess the precision of our spectral types (which were assigned by individual examination), review the bulk attributes of the sample, and examine the magnetic activity properties of M dwarfs, in particular those traced by the higher order Balmer transitions. Our catalog is cross-matched to Two Micron All Sky Survey infrared data, and contains photometric distances for each star. Finally, we identify eight new late-type M dwarfs that are possibly within 25 pc of the Sun. Future studies will use these data to thoroughly examine magnetic activity and kinematics in late-type M dwarfs and examine the chemical and dynamical history of the local Milky Way. Title: M Dwarf Flares: Exoplanet Implications Authors: Wisniewski, John; Kowalski, Adam; Schmidt, Sarah; Kundurthy, Praveen; Hawley, Suzanne; Tofflemire, Ben; Holtzman, Jon Bibcode: 2011noao.prop..106W Altcode: M dwarfs are attractive stars for exoplanet transit research as their low luminosities and small stellar radii could enable detection of super-Earths residing in their habitable zones. M dwarf flare events can cause <0.1 to 6.0 magnitude flux enhancements in the optical U- band, which is significantly higher than the predicted transit depths of super-Earths (~0.005 magnitude flux decrease). While Solar flares have been observed to cause infrared continuum enhancements (Xu et al 2006); surprisingly, it is not known whether energetic flares associated with M dwarfs can induce IR variability in filters relevant to future transiting exoplanet characterization studies (e.g. using JWST). We propose to monitor the optical & IR flux of a M dwarf known to regularly flare, to determine what effect flares could have on future IR characterization studies of M dwarf exoplanets. This proposal represents a resubmission of our approved 2009B program, which lost >80% of its on-sky time due to Tropical Storm Olaf (but did demonstrate the ability to achieve 5 milli-mag IR photometry with the KPNO 2.1m). We request 5 nights in 2011A to complete our science goals. Title: Extending M Dwarf Variability Studies to Longer Wavelengths Authors: Davenport, James R. A.; Becker, A.; Kowalski, A. F.; Hilton, E. J.; Hawley, S. L. Bibcode: 2011AAS...21724213D Altcode: 2011BAAS...4324213D Flares on M dwarfs occur stochastically, and the statistical frequency of such events is well characterized in the optical. Flares and stellar variability are a source of confusion for large time-domain surveys, and a unified physical model of these magnetically driven events across all spectral types still awaits discovery. To correctly predict the occurrence rate of M dwarf variability in future astronomical surveys, we must understand the full SED of these events as completely as possible. We have constructed a sample of 4000 M dwarfs with a broad range of properties, each with thousands of epochs of observation. This matched data set comes from the SDSS Stripe 82 and LINEAR databases in the optical, and 2MASS Calibration Scan database in the NIR. We present preliminary results that extend the flaring rate and variability signature to longer wavelengths, where many future scientific missions such as LSST, JWST, and others will operate. Title: M Dwarf Atomic and Molecular Features in SDSS DR7 Spectra Authors: Spencer, Meghin; Davenport, J. R. A.; West, A. A.; Hawley, S. L. Bibcode: 2011AAS...21724220S Altcode: 2011BAAS...4324220S Large, homogenous spectroscopic datasets offer the opportunity to investigate the behavior of stellar atmospheres as a function of various stellar parameters with unprecedented statistical accuracy. We use the SDSS DR7 spectroscopic catalog of 70,000 low mass stars to investigate the changes in atomic and molecular features that occur with differing mass, temperature, metallicity, and level of magnetic activity. Title: Optical and NIR Spectroscopy of ɛ Aurigae at Apache Point Observatory, the First Half of the Eclipse Authors: Ketzeback, William F.; Barentine, J.; Leadbeater, R.; McMillan, R.; Dembicky, J.; Saurage, G.; Huehnerhoff, J.; Schmidt, S.; Hawley, S.; Wallerstein, G.; Coughlin, J.; York, D. Bibcode: 2011AAS...21725705K Altcode: 2011BAAS...4325705K Epsilon Aurigae (ɛ Aur), first confirmed as a variable in 1821, is an eclipsing binary star system with a period of 27.1 years, one of the longest known. The primary, a pulsating F supergiant star with a variability out of eclipse of approximately 60 days and possible overtones of hundreds of days, is orbited by the secondary, a B-star enveloped by an enormous, cool, spectrally gray disk producing no evident wavelength dependence to the light output variations. The eclipse lasts for over 700 days; the current eclipse began first contact in July, 2009, and August 4, 2010 marked the estimated midway point of the eclipse. Although the components of the system have now been identified, much is still unclear such as the origin, composition and structure of the disk. Modern digital spectroscopy of bright stars not only enables asteroseismology and planetary detection, but the eclipsing binary epsilon Aurigae is an unusual case in which precise spectroscopic study of the now transiting dark disk is enabled. At Apache Point Observatory, our team has conducted high-resolution optical and NIR spectroscopic monitoring of this mysterious eclipsing system since February, 2009. We present major changes in the spectra attributable to the disk from the first half of the eclipse in the 0.4 - 2.2 μm range using ARCES, an optical echelle spectrograph (λ/Δλ=31,500), and Triplespec, a NIR cross-dispersed spectrograph (λ/Δλ=3500), on the ARC 3.5-meter telescope. Title: Revealing Stellar Magnetic Fields Through M Dwarf Flares Authors: Hilton, Eric J.; Hawley, S. L.; Kowalski, A. F. Bibcode: 2011AAS...21730702H Altcode: 2011BAAS...4330702H Magnetic reconnection on M dwarfs powers explosive flares with flux increases of several magnitudes in the blue/near-UV on timescales of minutes to hours. We obtained over 500 hours of flare monitoring observations at the Apache Point Observatory to make the first measurements of the flare frequency distribution of inactive early and mid M dwarfs and active late M dwarfs. These new measurements combined with our studies of flare rates from both SDSS photometry and spectroscopy have allowed us to construct a model of M dwarf flaring in the Galaxy that predicts the number and magnitude of flares expected in a given survey. In addition to the implications for time-domain surveys such as LSST, Pan-STARRS, and PTF, and for planet-habitability, the rate of flaring on stars of different mass and age informs our knowledge of the formation and evolution of stellar magnetic fields. We find that the flare star distribution is more concentrated toward the Galactic mid-plane than the active star population, implying that they are younger. Active stars flare more frequently and with more energy than inactive stars. Flares on late-type active M dwarfs are less energetic than those on earlier types.

We acknowledge support from NSF grant AST

08-07205. Title: An Optical Flare Rate Census of Galactic Bulge Dwarf Stars Authors: Kowalski, Adam; Osten, R. A.; Sahu, K. C.; Hawley, S. L. Bibcode: 2011AAS...21734207K Altcode: 2011BAAS...4334207K Flare emission is thought to be the observational consequence of transiently heated plasma by the dynamic interaction of magnetic fields throughout the stellar atmosphere. Other magnetic activity measures indicate that age may be a fundamental parameter for the generation and presence of surface magnetic fields. However, flares have been observed on both old and young stars, and the importance of age on the flare rate of a stellar population is not well known, as previous flare rate studies have been limited to the surrounding solar neighborhood and young disk population. The SWEEPS project monitored a 202x202 arcsec dense stellar field in the Sagittarius window of the Galactic bulge for a continuous seven-day period using the HST/ACS F606W (V) and F814W (I) filters. These data were aimed at a search for transiting exoplanets, but the high-cadence light curves, consisting of 260 epochs in each filter, provide a unique repository to mine for flare incidence in an evolved stellar population of dwarfs. We employ a customized algorithm to search for flares on 200,000 cool dwarfs of intermediate-old age, and we study the stellar flare rate and flare properties as a function of mass, V - I color, and the degree of underlying variability. These rates allow us to compare to the flare rates of younger stars and to extend the investigation of the evolution of magnetic activity to an older stellar population. Title: Making The Most Of Flaring M Dwarfs Authors: Hunt-Walker, Nicholas; Hilton, E.; Kowalski, A.; Hawley, S.; Matthews, J.; Holtzman, J. Bibcode: 2011AAS...21724224H Altcode: 2011BAAS...4324224H We present observations of flare activity using the Microvariability and Oscillations of Stars (MOST) satellite in conjunction with simultaneous spectroscopic and photometric observations from the ARC 3.5-meter, NMSU 1.0-meter, and ARCSAT 0.5-meter telescopes at the Apache Point Observatory. The MOST observations enable unprecedented completeness with regard to observing frequent, low-energy flares on the well-known dMe flare star AD Leo with broadband photometry. The observations span approximately one week with a 60-second cadence and are sensitive to flares as small as 0.01-magnitudes. The time-resolved, ground-based spectroscopy gives measurements of Hα and other important chromospheric emission lines, whereas the Johnson U-, SDSS u-, and SDSS g-band photometry provide color information during the flare events and allow us to relate the MOST observations to decades of previous broadband observations. Understanding the rates and energetics of flare events on M dwarfs will help characterize this source of variability in large time-domain surveys such as LSST and Pan-STARRS. Flare rates are also of interest to astrobiology, since flares affect the habitability of exoplanets orbiting M dwarfs. Title: X-ray and Radio Observations of LP349-25 Authors: Schmidt, Sarah J.; Osten, R. A.; Hawley, S. L.; Ngoc, P.; Reid, N. Bibcode: 2011AAS...21724218S Altcode: 2011BAAS...4324218S For a long time ultracool dwarfs (stellar objects with spectral types later than M7) were not thought to display any of the characteristics associated with the presence and action of strong magnetic fields, but surprisingly, recent observations have demonstrated the continuation of chromospheric and coronal indicators into this regime. The radio and X-ray behavior of ultracool dwarfs in particular show strikingly different behaviors when compared to what is seen in higher mass stars: objects detected at X-ray wavelengths show the decline of plasma heating with effective temperature but with examples of flare-like behavior which suggest some continuation in behavior from early-mid M dwarf stars. Radio detections of ultracool dwarfs are characterized by variability which occurs on timescales associated with the rotation period, and the dominant emission mechanism may switch from the incoherent gyrosynchrotron seen on earlier M stars to a coherent maser process. There is a discontinuity between radio-detected ultracool dwarfs (which tend to be X-ray weak or undetected) and X-ray detected ultracool dwarfs, which tend to be radio weak or undetected. The young brown dwarf binary LP 349-25 is a peculiar radio emitter due to its lack of radio variability on both long and short timescales. The lack of rotational modulation presents difficulties for the generation of radio emission in strong large scale magnetic fields. To further investigate the conditions of LP349-25, we present simultaneous radio and x-ray observations of LP349-25. Initial analysis of the data shows that the radio emission continues to be constant and that LP349-25 additionally shows quiescent x-ray emission. This allows us to place additional constraints on the mechanism for radio emission in LP349-25 and explore the conditions which cause disparate high energy behaviors in ultracool dwarfs. Title: M Dwarf Flares from Time-resolved Sloan Digital Sky Survey Spectra Authors: Hilton, Eric J.; West, Andrew A.; Hawley, Suzanne L.; Kowalski, Adam F. Bibcode: 2010AJ....140.1402H Altcode: 2010arXiv1009.1158H We have identified 63 flares on M dwarfs from the individual component spectra in the Sloan Digital Sky Survey (SDSS) using a novel measurement of emission-line strength called the Flare Line Index. Each of the ~38,000 M dwarfs in the SDSS low-mass star spectroscopic sample of West et al. was observed several times (usually 3-5) in exposures that were typically 9-25 minutes in duration. Our criteria allowed us to identify flares that exhibit very strong Hα and Hβ emission-line strength and/or significant variability in those lines throughout the course of the exposures. The flares we identified have characteristics consistent with flares observed by classical spectroscopic monitoring. The flare duty cycle for the objects in our sample is found to increase from 0.02% for early M dwarfs to 3% for late M dwarfs. We find that the flare duty cycle is larger in the population near the Galactic plane and that the flare stars are more spatially restricted than the magnetically active but non-flaring stars. This suggests that flare frequency may be related to stellar age (younger stars are more likely to flare) and that the flare stars are younger than the mean active population. Title: Solar Flares and the Chromosphere Authors: Fletcher, L.; Turkmani, R.; Hudson, H. S.; Hawley, S. L.; Kowalski, A.; Berlicki, A.; Heinzel, P. Bibcode: 2010arXiv1011.4650F Altcode: A white paper prepared for the Space Studies Board, National Academy of Sciences (USA), for its Decadal Survey of Solar and Space Physics (Heliophysics), reviewing and encouraging studies of flare physics in the chromosphere. Title: Solar Flares and the Chromosphere: A white paper for the Decadal Survey Authors: Hudson, H. S.; Fletcher, L.; Turkmani, R.; Hawley, S. L.; Kowalski, A. F.; Berlicki, A.; Heinzel, P. Bibcode: 2010helio2010....1H Altcode: No abstract at ADS Title: The Effect of a Strong Stellar Flare on the Atmospheric Chemistry of an Earth-like Planet Orbiting an M Dwarf Authors: Segura, Antígona; Walkowicz, Lucianne M.; Meadows, Victoria; Kasting, James; Hawley, Suzanne Bibcode: 2010AsBio..10..751S Altcode: 2010arXiv1006.0022S Main sequence M stars pose an interesting problem for astrobiology: their abundance in our galaxy makes them likely targets in the hunt for habitable planets, but their strong chromospheric activity produces high-energy radiation and charged particles that may be detrimental to life. We studied the impact of the 1985 April 12 flare from the M dwarf AD Leonis (AD Leo), simulating the effects from both UV radiation and protons on the atmospheric chemistry of a hypothetical, Earth-like planet located within its habitable zone. Based on observations of solar proton events and the Neupert effect, we estimated a proton flux associated with the flare of 5.9×108 protons cm-2 sr-1 s-1 for particles with energies >10 MeV. Then we calculated the abundance of nitrogen oxides produced by the flare by scaling the production of these compounds during a large solar proton event called the Carrington event. The simulations were performed with a 1-D photochemical model coupled to a 1-D radiative/convective model. Our results indicate that the UV radiation emitted during the flare does not produce a significant change in the ozone column depth of the planet. When the action of protons is included, the ozone depletion reaches a maximum of 94% two years after the flare for a planet with no magnetic field. At the peak of the flare, the calculated UV fluxes that reach the surface, in the wavelength ranges that are damaging for life, exceed those received on Earth during less than 100 s. Therefore, flares may not present a direct hazard for life on the surface of an orbiting habitable planet. Given that AD Leo is one of the most magnetically active M dwarfs known, this conclusion should apply to planets around other M dwarfs with lower levels of chromospheric activity. Title: OT1_shawley_2: Synchrotron Radiation in Stellar Flares Authors: Hawley, S. Bibcode: 2010hers.prop..879H Altcode: Stellar flares emit copious radiation at X-ray, optical and radio wavelengths but have not yet been investigated in the far-infrared. Recent observations at millimeter wavelengths provide tantalizing evidence that a population of ultrarelativistic electrons may be accelerated during flares and may provide significant synchrotron radiation in the far-infrared and sub-millimeter wavelength regimes. Herschel observations of two very active stars with a history of strong, frequent and energetic flares will probe this wavelength regime for the first time. Ultrarelativistic electrons may hold the key to explaining the photospheric flare heating that is necessary to produce the observed white light flare emission which carries more than half of the total flare energy. Our team brings together experts in stellar flare optical and radio observations, particle acceleration and plasma physics, and radiative hydrodynamical atmosphere modeling. We propose to carry out a Herschel flare observing campaign together with several ground-based optical and radio observatories and to produce a new generation of flare models that include the ultrarelativistic electron population. Title: The Milky Way Tomography with SDSS. III. Stellar Kinematics Authors: Bond, Nicholas A.; Ivezić, Željko; Sesar, Branimir; Jurić, Mario; Munn, Jeffrey A.; Kowalski, Adam; Loebman, Sarah; Roškar, Rok; Beers, Timothy C.; Dalcanton, Julianne; Rockosi, Constance M.; Yanny, Brian; Newberg, Heidi J.; Allende Prieto, Carlos; Wilhelm, Ron; Lee, Young Sun; Sivarani, Thirupathi; Majewski, Steven R.; Norris, John E.; Bailer-Jones, Coryn A. L.; Re Fiorentin, Paola; Schlegel, David; Uomoto, Alan; Lupton, Robert H.; Knapp, Gillian R.; Gunn, James E.; Covey, Kevin R.; Allyn Smith, J.; Miknaitis, Gajus; Doi, Mamoru; Tanaka, Masayuki; Fukugita, Masataka; Kent, Steve; Finkbeiner, Douglas; Quinn, Tom R.; Hawley, Suzanne; Anderson, Scott; Kiuchi, Furea; Chen, Alex; Bushong, James; Sohi, Harkirat; Haggard, Daryl; Kimball, Amy; McGurk, Rosalie; Barentine, John; Brewington, Howard; Harvanek, Mike; Kleinman, Scott; Krzesinski, Jurek; Long, Dan; Nitta, Atsuko; Snedden, Stephanie; Lee, Brian; Pier, Jeffrey R.; Harris, Hugh; Brinkmann, Jonathan; Schneider, Donald P. Bibcode: 2010ApJ...716....1B Altcode: 2009arXiv0909.0013B We study Milky Way kinematics using a sample of 18.8 million main-sequence stars with r < 20 and proper-motion measurements derived from Sloan Digital Sky Survey (SDSS) and POSS astrometry, including ~170,000 stars with radial-velocity measurements from the SDSS spectroscopic survey. Distances to stars are determined using a photometric-parallax relation, covering a distance range from ~100 pc to 10 kpc over a quarter of the sky at high Galactic latitudes (|b|>20°). We find that in the region defined by 1 kpc <Z< 5 kpc and 3 kpc <R< 13 kpc, the rotational velocity for disk stars smoothly decreases, and all three components of the velocity dispersion increase, with distance from the Galactic plane. In contrast, the velocity ellipsoid for halo stars is aligned with a spherical coordinate system and appears to be spatially invariant within the probed volume. The velocity distribution of nearby (Z < 1 kpc) K/M stars is complex, and cannot be described by a standard Schwarzschild ellipsoid. For stars in a distance-limited subsample of stars (<100 pc), we detect a multi-modal velocity distribution consistent with that seen by HIPPARCOS. This strong non-Gaussianity significantly affects the measurements of the velocity-ellipsoid tilt and vertex deviation when using the Schwarzschild approximation. We develop and test a simple descriptive model for the overall kinematic behavior that captures these features over most of the probed volume, and can be used to search for substructure in kinematic and metallicity space. We use this model to predict further improvements in kinematic mapping of the Galaxy expected from Gaia and the Large Synoptic Survey Telescope. Title: The Luminosity and Mass Functions of Low-mass Stars in the Galactic Disk. II. The Field Authors: Bochanski, John J.; Hawley, Suzanne L.; Covey, Kevin R.; West, Andrew A.; Reid, I. Neill; Golimowski, David A.; Ivezić, Željko Bibcode: 2010AJ....139.2679B Altcode: 2010arXiv1004.4002B We report on new measurements of the luminosity function (LF) and mass function (MF) of field low-mass dwarfs derived from Sloan Digital Sky Survey Data Release 6 photometry. The analysis incorporates ~15 million low-mass stars (0.1 {\cal M}_\odot {\cal M} < 0.8\,{\cal M}_\odot), spread over 8400 deg2. Stellar distances are estimated using new photometric parallax relations, constructed from ugriz photometry of nearby low-mass stars with trigonometric parallaxes. We use a technique that simultaneously measures Galactic structure and the stellar LF from 7 < Mr < 16. We compare the LF to previous studies and convert to an MF using the mass-luminosity relations of Delfosse et al. The system MF, measured over -1.0< log {\cal M} / {\cal M}_\odot <-0.1, is well described by a lognormal distribution with {\cal M}_{\circ } = 0.25 {\cal M}_\odot. We stress that our results should not be extrapolated to other mass regimes. Our work generally agrees with prior low-mass stellar MFs and places strong constraints on future theoretical star formation studies. Title: Colors and Kinematics of L Dwarfs from the Sloan Digital Sky Survey Authors: Schmidt, Sarah J.; West, Andrew A.; Hawley, Suzanne L.; Pineda, J. Sebastian Bibcode: 2010AJ....139.1808S Altcode: 2010arXiv1001.3402S We present a sample of 484 L dwarfs, 210 of which are newly discovered from the Sloan Digital Sky Survey (SDSS) Data Release 7 spectroscopic database. We combine this sample with known L dwarfs to investigate their izJHKS colors. Our spectroscopically selected sample has ~0.1 mag bluer median J - KS color at a given spectral type (for L0-L4) than previously known L dwarfs, which reflects a bias toward redder L dwarfs in past selection criteria. We present photometric distance relations based on i - z and i - J colors and derive distances to our L dwarf sample. We combine the distances with SDSS/2MASS proper motions in order to examine the tangential velocities. For the majority of our spectroscopic sample, we measured radial velocities and present three-dimensional kinematics. We also provide Hα detections for the fraction of our sample with sufficient quality spectra. Comparison of the velocities of our L dwarf sample to a kinematic model shows evidence for both cold and hot dynamical populations, consistent with young and old disk components. The dispersions of these components are similar to those found for M dwarfs. We also show that J - KS color is correlated with velocity dispersion, confirming a relationship between J - KS color and age. Title: A White Light Megaflare on the dM4.5e Star YZ CMi Authors: Kowalski, Adam F.; Hawley, Suzanne L.; Holtzman, Jon A.; Wisniewski, John P.; Hilton, Eric J. Bibcode: 2010ApJ...714L..98K Altcode: 2010arXiv1003.3057K On UT 2009 January 16, we observed a white light megaflare on the dM4.5e star YZ CMi as part of a long-term spectroscopic flare-monitoring campaign to constrain the spectral shape of optical flare continuum emission. Simultaneous U-band photometric and 3350-9260 Å spectroscopic observations were obtained during 1.3 hr of the flare decay. The event persisted for more than 7 hr and at flare peak, the U-band flux was almost 6 mag brighter than in the quiescent state. The properties of this flare mark it as one of the most energetic and longest-lasting white light flares ever to be observed on an isolated low-mass star. We present the U-band flare energetics and a flare continuum analysis. For the first time, we show convincingly with spectra that the shape of the blue continuum from 3350 Å to 4800 Å can be represented as a sum of two components: a Balmer continuum as predicted by the Allred et al. radiative hydrodynamic flare models and a T~ 10,000 K blackbody emission component as suggested by many previous studies of the broadband colors and spectral distributions of flares. The areal coverage of the Balmer continuum and blackbody emission regions vary during the flare decay, with the Balmer continuum emitting region always being significantly (~3-16 times) larger. These data will provide critical constraints for understanding the physics underlying the mysterious blue continuum radiation in stellar flares.

Based on observations obtained with the Apache Point Observatory 3.5 m Telescope, which is owned and operated by the Astrophysical Research Consortium. Title: Discovery of an Unusually Blue L Dwarf Within 10 pc of the Sun Authors: Schmidt, Sarah J.; West, Andrew A.; Burgasser, Adam J.; Bochanski, John J.; Hawley, Suzanne L. Bibcode: 2010AJ....139.1045S Altcode: 2009arXiv0912.3565S We report the discovery of an unusually blue L5 dwarf within 10 pc of the Sun from a search of Sloan Digital Sky Survey (SDSS) spectra. A spectrophotometric distance estimate of 8.0 ± 1.6 pc places SDSS J141624.08+134826.7 among the six closest known L dwarfs. SDSS 1416+13 was overlooked in infrared color-based searches because of its unusually blue J - K S color, which also identifies it as the nearest member of the blue L dwarf subclass. We present additional infrared and optical spectroscopy from the IRTF/SpeX and Magellan/MagE spectrographs and determine UVW motions that indicate thin disk kinematics. The inclusion of SDSS 1416+13 in the 20 pc sample of L dwarfs increases the number of L5 dwarfs by 20% suggesting that the L dwarf luminosity function may be far from complete.

This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile. Title: A White Light Megaflare on the dM4.5e Star YZ CMi Authors: Kowalski, Adam; Hawley, S. L.; Holtzman, J. A.; Wisniewski, J. P.; Hilton, E. J. Bibcode: 2010AAS...21542411K Altcode: 2010BAAS...42..332K Due to their strong and persistent surface magnetic fields, some M dwarfs frequently produce very explosive and energetic flares in the optical and near-UV. However, observations and radiative hydrodynamic simulations of flares are in stark disagreement over the type of emission which characterizes the continuum at these wavelengths. On January 16, 2009, we observed a white light megaflare on the dM4.5e star YZ CMi as part of a long-term spectroscopic flare-monitoring campaign to constrain the spectral shape of optical flare emission. This flare was observed with simultaneous U-band photometry and 3400 A - 9000 A spectroscopy with the NMSU 1 m and ARC 3.5 m telescopes at the Apache Point Observatory. The event persisted for over 7.5 hours and at the flare peak, YZ CMi's U-band flux was 5.8 magnitudes brighter than in its quiescent state. The properties of this flare mark it as one of the most energetic and long-lasting white light flares ever to be observed on an isolated star. We present the detailed light curve properties and a time-resolved spectral analysis of the continuum and emission lines using over 160 spectra obtained during 1.3 hours of the decay phase of the flare, during which there were complex light curve variations with the U-band flux still elevated at 15-38 times the quiescent level.

AFK, SLH, & EJH acknowledge support from NSF grant AST 0807205

JPW acknowledges support from NSF Astronomy & Astrophysics Postdoctoral Fellowship AST 08-02230 Title: Stellar Population Science with LSST Authors: Covey, Kevin R.; Saha, A.; Beers, T. C.; Bochanski, J. J.; Boeshaar, P.; Burgasser, A.; Cargile, P.; Chu, Y.; Claver, C.; Cook, K.; Dhital, S.; Hawley, S. L.; Hebb, L.; Henry, T. J.; Hilton, E.; Holberg, J. B.; Ivezic, Z.; Juric, M. L.; Kafka, S.; Kalirai, J.; Lepine, S.; Macri, L.; McGehee, P. M.; Monet, D.; Olsen, K.; Pepper, J.; Prsa, A.; Sarajedini, A.; Silvestri, N.; Stassun, K.; Thorman, P.; West, A. A.; Williams, B. F. Bibcode: 2010AAS...21540108C Altcode: 2010BAAS...42..218C The LSST will produce a multi-color photometric catalog of half the sky to r=27.6 (AB mag; 5-sigma). Multi-epoch observations over the survey's ten year baseline will allow variability, proper motion and parallax measurements for objects as faint as r=24.7. These capabilities allow LSST to identify and characterize resolved stellar populations in unprecedented breadth and detail, enabling a more comprehensive and nuanced understanding of the star formation history of the Milky Way and nearby galaxies. The stellar populations science that LSST will enable includes: completing the solar neighborhood census by measuring accurate parallaxes (sigmapi = 6 mas) and proper motions (sigmapm = 2 mas/yr) for low--mass stars and brown dwarfs to a very faint limit (y < 21.4); assembling large samples of eclipsing binaries, subdwarfs and white dwarfs to measure fundamental physical parameters of stars and stellar systems; enabling photometric metallicity determinations (down to [Fe/H] = -2.5, or lower) for main-sequence stars in the LSST footprint; constructing a comprehensive, homogeneous census of southern star clusters to characterize stellar evolution as a function of age and chemical composition; measure the star formation history of the Milky Way's thin disk over the last 2-3 Gyrs by interpreting rotation periods of solar analogs with calibrated gyrochronology relations; mapping the location, chemistry, and ages of stars turning off the main-sequence (MS) at all distances within the Galaxy, Magellanic Clouds, and dwarf satellites of the Milky Way; map out the star formation history and structure of the Magellanic clouds to distances exceeding 15 degrees and surface brightness densities below 35 mags. per square arc sec; fine tuning the extragalactic distance scale by examining properties of RR Lyraes and Cepheids as a function of parent populations. Title: Connecting the Time Domain Photometry of M Dwarfs with Low-Resolution Spectroscopy Authors: West, Andrew A.; Kowlaski, A. F.; Becker, A. C.; Bochanski, J. J.; Hawley, S. L. Bibcode: 2010AAS...21542420W Altcode: 2010BAAS...42R.333W We present a study of the lightcurves and spectra of 18,000 M dwarfs from the Sloan Digital Sky Survey (SDSS). Our sample was selected to have both multi-epoch observations from SDSS's Stripe 82 (resulting in 60 separate observations in each band), as well as SDSS low-resolution spectra for each star. A majority of the photometric variation in these stars is thought to be caused by long-lived star spots that modulate the light as the star rotates. The amplitude of the variation in all of the SDSS bands gives us important insight into the spot coverage and temperature. We investigate how this amplitude changes as a function of various quantities derived from the spectra, namely spectral type, magnetic activity (thought to be connected to the star spots), and dynamical age. This sample and its ties to spectroscopic observations will help inform and add value to upcoming (and current) time domain surveys such as LSST. Title: M Dwarf Flares: Exoplanet Implications Authors: Tofflemire, Benjamin M.; Wisniewski, J. P.; Kowalski, A. F.; Schmidt, S. J.; Kundurthy, P.; Hawley, S. L.; Hilton, E. J. Bibcode: 2010AAS...21542315T Altcode: 2010BAAS...42..328T Low mass stars such as M dwarfs are prime targets for exoplanet transit searches as their low luminosities and small stellar radii could enable detection of super-Earths residing in their habitable zones. While promising targets for transit searches, M dwarfs are also inherently variable and can exhibit up to 6 magnitude flux enhancements in the optical U-band. This is significantly higher than the predicted transit depths of super-Earths (0.005 magnitude flux decrease). The behavior of flares at IR wavelengths, particularly those likely to be used to study and characterize M dwarf exoplanets using facilities such as JWST, remains largely unknown. To address these uncertainties, we have executed a coordinated, contemporaneous monitoring program of the optical and IR flux of M dwarfs known to regularly flare. A suite of telescopes located at the Kitt Peak National Observatory and the Apache Point Observatory were used for the observations. We present the initial results of this program and discuss how flare events could influence future exoplanet detection and characterization studies in the IR.

JPW acknowledges support from a NSF Astronomy and Astrophysics Postdoctoral Fellowship, AST 08-02230. Title: TYC 1240-945-1b: First Brown Dwarf Candidate from the SDSS-III-MARVELS Planet Search Authors: Lee, Brian L.; Ge, J.; Fleming, S. W.; Mahadevan, S.; Sivarani, T.; De Lee, N.; Dou, L.; Jiang, P.; Xie, J.; Gaudi, B. S.; Eastman, J.; Pepper, J.; Stassun, K.; Gary, B.; Wisniewski, J. P.; Barnes, R.; Kane, S. R.; van Eyken, J. C.; Wang, J.; Chang, L.; Costello, E.; Fletcher, A.; Groot, J.; Guo, P.; Hanna, K.; Malik, M.; Rohan, P.; Varosi, F.; Wan, X.; Zhao, B.; Hearty, F.; Shelden, A.; Leger, F.; Long, D.; Agol, E.; Ford, E. B.; Ford, H. C.; Holtzman, J. A.; Schneider, D.; Weinberg, D. H.; Eisenstein, D.; Hawley, S.; Snedden, S.; Bizyaev, D.; Brewington, H.; Malanushenko, V.; Malanushenko, E.; Oravetz, D.; Pan, K.; Simmons, A. Bibcode: 2010AAS...21547204L Altcode: 2010BAAS...42..519L We present a new brown dwarf candidate, TYC 1240-945-1b, discovered in the first year of MARVELS, a multi-object radial velocity (RV) planet search which is part of the Sloan Digital Sky Survey (SDSS-III). From our RV discovery data taken at 15 epochs spread over a 100d time baseline at the SDSS 2.5-m telescope, we derive a preliminary characterization of the orbit with semi-amplitude K=2.5 km/s, period P=5.9d, and no detectable eccentricity. Adopting a mass of 1.2 solar masses for the F9V host star TYC 1240-945-1, we infer that the candidate has Msini 26MJup and semimajor axis 0.068AU. In addition to exhibiting the discovery data, we show the pre-survey and follow-up spectroscopic observations that have been taken to further refine the stellar parameters for the host star.

This work was supported by the W.M. Keck Foundation, NSF, SDSS-III consortium, NASA, and UF. Title: The Continued Optical to Mid-IR Evolution of V838 Monocerotis Authors: Loebman, Sarah; Wisniewski, J. P.; Kowalski, A. F.; Barry, R. K.; Bjorkman, K. S.; Bond, H. E.; Clampin, M.; Hammel, H. B.; Hawley, S. L.; Lynch, D. K.; Munshi, F. A.; Russell, R. W.; Schmidt, S. J.; Sitko, M. L. Bibcode: 2010AAS...21543115L Altcode: 2010BAAS...42..364L V838 Monocerotis is an eruptive variable which gained notoriety in 2002 when it brightened by 9 magnitudes in a series of outbursts, and eventually developed a spectacular light echo. The star's mid-IR flux increased by a factor of 2 between 2004 and 2007, suggesting that new dust was condensing from the expanding ejecta of the outbursts, while more recent optical spectroscopic observations suggest that these expanding ejecta have engulfed the system's B3V binary companion. We present new optical, near-IR, and mid-IR spectroscopic and mid-IR photometric observations of V838 Monocerotis obtained between 2008-2009 at the Apache Point Observatory 3.5m, NASA IRTF 3m, and Gemini South 8m telescopes. We discuss the chemistry and continued evolution of recently formed dust in the system in the context of previously published photometric, spectroscopic, and spectro-polarimetric observations of the system.

This work is supported at The Aerospace Corporation by the Independent Research and Development program; JPW acknowledges support from a NSF Astronomy & Astrophysics Postdoctoral Fellowship, AST 08-02230. Title: The SDSS-III MARVELS Survey: The First Year Authors: De Lee, Nathan M.; Ge, J.; Lee, B.; Mahadevan, S.; Fleming, S. W.; Sivarani, T.; Wan, X.; Groot, J.; Zhao, B.; Varosi, F.; Hanna, K.; Hearty, F.; Chang, L.; Liu, J.; Rohan, P.; van Eyken, J. C.; Wang, J.; Guo, P.; Malik, M.; Shelden, A.; Kane, S. R.; Costello, E.; Fletcher, A.; Ford, E. B.; Agol, E.; Bochanski, J. J.; Ford, H.; Gaudi, S.; Holtzman, J.; Schneider, D. P.; Seager, S.; Weinberg, D.; Eisenstein, D.; Leger, F.; Long, D.; Snedden, S.; Pan, K.; Bizyaev, D.; Brewington, H.; Malanushenko, E.; Malanushenko, V.; Oravetz, D.; Simmons, A.; Hawley, S. Bibcode: 2010AAS...21547205D Altcode: 2010BAAS...42..519D The Sloan Digital Sky Survey (SDSS-III) MARVELS (Multi-object Apache point observatory Radial Velocity Exo-planet Large-area Survey) project is currently in its second year of operation. The MARVELS survey is currently searching for giant planets around a large and diverse set of host stars from F, G, and K dwarfs and subgiants to G and K giants. The MARVELS survey has already canvassed over 2500 stars primarily ranging in V magnitude from 7.6 to 12.

This presentation will cover an overview of the MARVELS Survey including operations and data processing during the first year of observing. There will also be a discussion of the ongoing analysis of the MARVELS radial velocity curves. This analysis will consider identification of variable objects, period searching, and ultimately identifying MARVELS candidates for binaries, brown dwarfs, and planets. Early results from the first year of operation will be shown.

We wish to acknowledge support from the W.M. Keck Foundation, NSF, SDSS-III consortium, NASA and UF. Title: Flares on M Dwarfs from a Time-Resolved SDSS Spectral Sample Authors: Hilton, Eric J.; Hawley, S. L.; West, A. A.; Kowalski, A. F. Bibcode: 2010AAS...21542410H Altcode: 2010BAAS...42..332H We present flare rates and analysis of individual flares using time-resolved spectra of M dwarfs from the Sloan Digital Sky Survey Data Release 5. Each of the 40,000 M dwarf spectra from the West et al. (2008) DR5 sample represents a co-addition of several shorter (9-15 min) spectra. We analyze nearly 200,000 of these short spectra, subdividing them by spectral type and by signal-to-noise ratio and use statistical methods to assign variability and flaring status. These data allow us to investigate the spectroscopic time-domain properties of low-mass stars. Title: Color and Kinematics of L dwarfs From the Sloan Digital Sky Survey Authors: Schmidt, Sarah J.; West, A. A.; Hawley, S. L.; Pineda, J. S. Bibcode: 2010AAS...21542426S Altcode: 2010BAAS...42Q.335S We present a sample of 484 L dwarfs from the Sloan Digital Sky Survey (SDSS) spectroscopic database, selected primarily using spectroscopic criteria. Our SDSS L dwarf sample has a bluer median J-Ks color at each spectral type than samples of L dwarfs selected using infrared colors, which reflects a bias towards redder J-Ks in previously known L dwarfs. Distances are estimated using newly derived photometric parallax relations in i-z and i-J, and are combined with radial velocities and proper motions to calculate full space motions. As a single population, L dwarfs do not appear to be kinematically cooler (younger) than M dwarfs. However, our sample is better fit by a two-population model with hot and cold components, consistent with young and old disk populations. We also find that bluer objects have a larger velocity dispersion than redder objects of the same spectral type, indicating that the J-Ks color may be a good tracer of age. Title: Early Results of a High-Resolution Spectroscopic Monitoring Program of the Mysterious Eclipsing Binary Authors: Ketzeback, W.; McMillan, R.; Dembicky, J.; Saurage, G.; Huehnerhoff, J.; Coughlin, J.; Barentine, J.; Schmidt, S.; Hawley, S.; Wallerstein, G. Bibcode: 2010neme.confP...2K Altcode: No abstract at ADS Title: Flare Rates in Low-Mass Stars Authors: Krogsrud, David; Davenport, J. R. A.; Reid, I. N.; Hawley, S. L. Bibcode: 2009AAS...21360102K Altcode: Low-mass stars constitute a large majority of the total population of stars in our galaxy, yet relatively little is known about their properties. This is largely a consequence of the difficulty of observing them due to their intrinsic dimness. As they are so common, low-mass stars are a large potential source of noise in numerous variability studies including extra-solar planet and novae surveys. Flare rates for these stars are also important in constraining the characteristics of their magnetic dynamos. In this study, we look at the open cluster IC 2391, observing three fields in U and I Johnson-Cousins filters. The data come from the CTIO 0.9m telescope. Twenty-three late-type stars are monitored, half of which have previously published I magnitudes. We present preliminary results

of the activity rates of these stars. Title: LSST Science Book, Version 2.0 Authors: LSST Science Collaboration; Abell, Paul A.; Allison, Julius; Anderson, Scott F.; Andrew, John R.; Angel, J. Roger P.; Armus, Lee; Arnett, David; Asztalos, S. J.; Axelrod, Tim S.; Bailey, Stephen; Ballantyne, D. R.; Bankert, Justin R.; Barkhouse, Wayne A.; Barr, Jeffrey D.; Barrientos, L. Felipe; Barth, Aaron J.; Bartlett, James G.; Becker, Andrew C.; Becla, Jacek; Beers, Timothy C.; Bernstein, Joseph P.; Biswas, Rahul; Blanton, Michael R.; Bloom, Joshua S.; Bochanski, John J.; Boeshaar, Pat; Borne, Kirk D.; Bradac, Marusa; Brandt, W. N.; Bridge, Carrie R.; Brown, Michael E.; Brunner, Robert J.; Bullock, James S.; Burgasser, Adam J.; Burge, James H.; Burke, David L.; Cargile, Phillip A.; Chandrasekharan, Srinivasan; Chartas, George; Chesley, Steven R.; Chu, You-Hua; Cinabro, David; Claire, Mark W.; Claver, Charles F.; Clowe, Douglas; Connolly, A. J.; Cook, Kem H.; Cooke, Jeff; Cooray, Asantha; Covey, Kevin R.; Culliton, Christopher S.; de Jong, Roelof; de Vries, Willem H.; Debattista, Victor P.; Delgado, Francisco; Dell'Antonio, Ian P.; Dhital, Saurav; Di Stefano, Rosanne; Dickinson, Mark; Dilday, Benjamin; Djorgovski, S. G.; Dobler, Gregory; Donalek, Ciro; Dubois-Felsmann, Gregory; Durech, Josef; Eliasdottir, Ardis; Eracleous, Michael; Eyer, Laurent; Falco, Emilio E.; Fan, Xiaohui; Fassnacht, Christopher D.; Ferguson, Harry C.; Fernandez, Yanga R.; Fields, Brian D.; Finkbeiner, Douglas; Figueroa, Eduardo E.; Fox, Derek B.; Francke, Harold; Frank, James S.; Frieman, Josh; Fromenteau, Sebastien; Furqan, Muhammad; Galaz, Gaspar; Gal-Yam, A.; Garnavich, Peter; Gawiser, Eric; Geary, John; Gee, Perry; Gibson, Robert R.; Gilmore, Kirk; Grace, Emily A.; Green, Richard F.; Gressler, William J.; Grillmair, Carl J.; Habib, Salman; Haggerty, J. S.; Hamuy, Mario; Harris, Alan W.; Hawley, Suzanne L.; Heavens, Alan F.; Hebb, Leslie; Henry, Todd J.; Hileman, Edward; Hilton, Eric J.; Hoadley, Keri; Holberg, J. B.; Holman, Matt J.; Howell, Steve B.; Infante, Leopoldo; Ivezic, Zeljko; Jacoby, Suzanne H.; Jain, Bhuvnesh; R; Jedicke; Jee, M. James; Garrett Jernigan, J.; Jha, Saurabh W.; Johnston, Kathryn V.; Jones, R. Lynne; Juric, Mario; Kaasalainen, Mikko; Styliani; Kafka; Kahn, Steven M.; Kaib, Nathan A.; Kalirai, Jason; Kantor, Jeff; Kasliwal, Mansi M.; Keeton, Charles R.; Kessler, Richard; Knezevic, Zoran; Kowalski, Adam; Krabbendam, Victor L.; Krughoff, K. Simon; Kulkarni, Shrinivas; Kuhlman, Stephen; Lacy, Mark; Lepine, Sebastien; Liang, Ming; Lien, Amy; Lira, Paulina; Long, Knox S.; Lorenz, Suzanne; Lotz, Jennifer M.; Lupton, R. H.; Lutz, Julie; Macri, Lucas M.; Mahabal, Ashish A.; Mandelbaum, Rachel; Marshall, Phil; May, Morgan; McGehee, Peregrine M.; Meadows, Brian T.; Meert, Alan; Milani, Andrea; Miller, Christopher J.; Miller, Michelle; Mills, David; Minniti, Dante; Monet, David; Mukadam, Anjum S.; Nakar, Ehud; Neill, Douglas R.; Newman, Jeffrey A.; Nikolaev, Sergei; Nordby, Martin; O'Connor, Paul; Oguri, Masamune; Oliver, John; Olivier, Scot S.; Olsen, Julia K.; Olsen, Knut; Olszewski, Edward W.; Oluseyi, Hakeem; Padilla, Nelson D.; Parker, Alex; Pepper, Joshua; Peterson, John R.; Petry, Catherine; Pinto, Philip A.; Pizagno, James L.; Popescu, Bogdan; Prsa, Andrej; Radcka, Veljko; Raddick, M. Jordan; Rasmussen, Andrew; Rau, Arne; Rho, Jeonghee; Rhoads, James E.; Richards, Gordon T.; Ridgway, Stephen T.; Robertson, Brant E.; Roskar, Rok; Saha, Abhijit; Sarajedini, Ata; Scannapieco, Evan; Schalk, Terry; Schindler, Rafe; Schmidt, Samuel; Schmidt, Sarah; Schneider, Donald P.; Schumacher, German; Scranton, Ryan; Sebag, Jacques; Seppala, Lynn G.; Shemmer, Ohad; Simon, Joshua D.; Sivertz, M.; Smith, Howard A.; Allyn Smith, J.; Smith, Nathan; Spitz, Anna H.; Stanford, Adam; Stassun, Keivan G.; Strader, Jay; Strauss, Michael A.; Stubbs, Christopher W.; Sweeney, Donald W.; Szalay, Alex; Szkody, Paula; Takada, Masahiro; Thorman, Paul; Trilling, David E.; Trimble, Virginia; Tyson, Anthony; Van Berg, Richard; Vanden Berk, Daniel; VanderPlas, Jake; Verde, Licia; Vrsnak, Bojan; Walkowicz, Lucianne M.; Wandelt, Benjamin D.; Wang, Sheng; Wang, Yun; Warner, Michael; Wechsler, Risa H.; West, Andrew A.; Wiecha, Oliver; Williams, Benjamin F.; Willman, Beth; Wittman, David; Wolff, Sidney C.; Wood-Vasey, W. Michael; Wozniak, Przemek; Young, Patrick; Zentner, Andrew; Zhan, Hu Bibcode: 2009arXiv0912.0201L Altcode: A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of the exciting science opportunities of the next decade. The Large Synoptic Survey Telescope (LSST) will have an effective aperture of 6.7 meters and an imaging camera with field of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over 20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a total point-source depth of r~27.5. The LSST Science Book describes the basic parameters of the LSST hardware, software, and observing plans. The book discusses educational and outreach opportunities, then goes on to describe a broad range of science that LSST will revolutionize: mapping the inner and outer Solar System, stellar populations in the Milky Way and nearby galaxies, the structure of the Milky Way disk and halo and other objects in the Local Volume, transient and variable objects both at low and high redshift, and the properties of normal and active galaxies at low and high redshift. It then turns to far-field cosmological topics, exploring properties of supernovae to z~1, strong and weak lensing, the large-scale distribution of galaxies and baryon oscillations, and how these different probes may be combined to constrain cosmological models and the physics of dark energy. Title: VizieR Online Data Catalog: X-emitting stars identified from the RASS/SDSS (Agueros+, 2009) Authors: Agueros, M. A.; Anderson, S. F.; Covey, K. R.; Hawley, S. L.; Margon, B.; Newsom, E. R.; Posselt, B.; Silvestri, N. M.; Szkody, P.; Voges, W. Bibcode: 2009yCat..21810444A Altcode: The ROSAT All-Sky Survey (RASS) was the first imaging X-ray survey of the entire sky. Combining the RASS Bright and Faint Source Catalogs (Cat. <IX/10>, 1RXS and <IX/29>) yields an average of about three X-ray sources per square degree. However, while X-ray source counterparts are known to range from distant quasars to nearby M dwarfs, the RASS data alone are often insufficient to determine the nature of an X-ray source. As a result, large-scale follow-up programs are required to construct samples of known X-ray emitters. We use optical data produced by the Sloan Digital Sky Survey (SDSS) to identify 709 stellar X-ray emitters cataloged in the RASS and falling within the SDSS Data Release 1 footprint. Most of these are bright stars with coronal X-ray emission unsuitable for SDSS spectroscopy, which is designed for fainter objects (g>15[mag]). Instead, we use SDSS photometry, correlations with the Two Micron All Sky Survey and other catalogs, and spectroscopy from the Apache Point Observatory 3.5m telescope to identify these stellar X-ray counterparts. Our sample of 707 X-ray-emitting F, G, K, and M stars is one of the largest X-ray-selected samples of such stars. We identify 17 new X-ray-emitting DA (hydrogen) WDs, of which three are newly identified WDs. We report on follow-up observations of three candidate cool X-ray-emitting WDs (one DA and two DB (helium) WDs); we have not confirmed X-ray emission from these WDs.

(7 data files). Title: Spectroscopic Study of NSVS RR Lyrae Stars: Preliminary Metallicity Results Authors: Kinemuchi, K.; Wallerstein, G.; Preston, G.; Walkowicz, L.; Fraser, O.; Bochanski, J.; Hawley, S. Bibcode: 2009AIPC.1170..191K Altcode: The Northern Sky Variability Survey (NSVS) is an all-sky photometric survey of variable objects found down to V~15. The NSVS probes the disk and inner halo components of the Milky Way Galaxy. Field RR Lyrae (RRL) variable stars have been identified and analyzed. We have begun a campaign to obtain spectra for many of these new RRL stars. Mid-resolution spectra were obtained using the Dual Imaging Spectrograph on the ARC 3.5 m telescope at Apache Point Observatory over a span of 2 years. We have collected 89 spectra of RRL stars, which were selected for their possible membership of the thick and thin disk components. We have also included RRL stars with long periods (P>0.75 days). We present the driving science and goals of these projects, and preliminary results from the mid-resolution spectra. Title: Steady and Transient Radio Emission from Ultracool Dwarfs Authors: Osten, Rachel A.; Phan-Bao, N.; Hawley, Suzanne L.; Reid, I. Neill; Ojha, Roopesh Bibcode: 2009ApJ...700.1750O Altcode: 2009arXiv0905.4197O We present the results of multi-frequency radio observing campaigns designed to elucidate the nature of radio emission from very low mass stars. We detect radio emission in an additional two epochs of the ultracool dwarf binary LP 349-25, finding that the observed emission is broad band and steady on timescales between 10 s and 10.7 hr, as well as on timescales of 0.6 and 1.6 years. This system is unusual for ultracool dwarfs with detectable radio emission, in exhibiting a lack of any large-scale variability, particularly the bursting (periodic or aperiodic) behavior exhibited by the other objects with detectable levels of radio emission. We explore the constraints that the lack of variability on long- and short-timescales, and flat spectral index, imply about the radio-emitting structures and mechanism. The temporal constraints argue for a high latitude emitting region with a large inclination so that it is always in view, and survives for at least 0.6 years. Temporal constraints also limit the plasma conditions, implying that the electron density be ne < 4 × 105 cm-3 and B< 130 G in order not to see time variations due to collisional or radiative losses from high-energy particles. The observations and constraints provided by them are most compatible with a nonthermal radio emission mechanism, likely gyrosynchrotron emission from a spatially homogeneous or inhomogeneous source. This indicates that, similar to behaviors noted for chromospheric, transition region, and coronal plasmas in ultracool dwarfs, the magnetic activity patterns observed in active higher mass stars can survive to the substellar boundary. We also present new epochs of multi-frequency radio observations for the ultracool dwarfs 2MASS 05233822-140322 and 2MASS14563831-2809473(=LHS 3003); each has been detected in at least one previous epoch but are not detected in the epochs reported here. The results here suggest that magnetic configurations in ultracool dwarfs can be long-lasting, and support the need for further radio monitoring using a simultaneous, multi-frequency observing approach. Title: M Dwarfs in Sloan Digital Sky Survey Stripe 82: Photometric Light Curves and Flare Rate Analysis Authors: Kowalski, Adam F.; Hawley, Suzanne L.; Hilton, Eric J.; Becker, Andrew C.; West, Andrew A.; Bochanski, John J.; Sesar, Branimir Bibcode: 2009AJ....138..633K Altcode: 2009arXiv0906.2030K We present a flare rate analysis of 50,130 M dwarf light curves in Sloan Digital Sky Survey Stripe 82. We identified 271 flares using a customized variability index to search ~2.5 million photometric observations for flux increases in the u and g bands. Every image of a flaring observation was examined by eye and with a point-spread function-matching and image subtraction tool to guard against false positives. Flaring is found to be strongly correlated with the appearance of Hα in emission in the quiet spectrum. Of the 99 flare stars that have spectra, we classify eight as relatively inactive. The flaring fraction is found to increase strongly in stars with redder colors during quiescence, which can be attributed to the increasing flare visibility and increasing active fraction for redder stars. The flaring fraction is strongly correlated with |Z| distance such that most stars that flare are within 300 pc of the Galactic plane. We derive flare u-band luminosities and find that the most luminous flares occur on the earlier-type m dwarfs. Our best estimate of the lower limit on the flaring rate (averaged over Stripe 82) for flares with Δu >= 0.7 mag on stars with u < 22 is 1.3 flares hr-1 deg-2 but can vary significantly with the line of sight.

Based on observations obtained with the Apache Point Observatory 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium. Title: M Dwarf Flares: Exoplanet Implications Authors: Wisniewski, John; Kowalski, Adam; Schmidt, Sarah; Hawley, Suzanne; Kundurthy, Praveen Bibcode: 2009noao.prop..280W Altcode: Low mass M dwarfs are attractive stars for exoplanet transit research as their low luminosities and small stellar radii could enable detection of super-Earths residing in their habitable zones using existing technology. Future IR facilities such as JWST will undoubtedly attempt to characterize these systems through detailed transit observations. M dwarfs can exhibit highly energetic flare events which cause <0.1 to 6.0 magnitude flux enhancements in the optical U-band, which is significantly higher than the predicted transit depths of super- Earths (~0.005 magnitude flux decrease). While Solar flares have been observed to cause IR continuum enhancements (Xu et al 2006); surprisingly, it is not known whether energetic flares associated with M dwarfs similarly induce IR variability. We propose to contemporaneously monitor the optical & IR flux of two M dwarfs known to regularly flare, to determine what effect flares could have on future IR characterization studies of M dwarf exoplanets. Title: The Seventh Data Release of the Sloan Digital Sky Survey Authors: Abazajian, Kevork N.; Adelman-McCarthy, Jennifer K.; Agüeros, Marcel A.; Allam, Sahar S.; Allende Prieto, Carlos; An, Deokkeun; Anderson, Kurt S. J.; Anderson, Scott F.; Annis, James; Bahcall, Neta A.; Bailer-Jones, C. A. L.; Barentine, J. C.; Bassett, Bruce A.; Becker, Andrew C.; Beers, Timothy C.; Bell, Eric F.; Belokurov, Vasily; Berlind, Andreas A.; Berman, Eileen F.; Bernardi, Mariangela; Bickerton, Steven J.; Bizyaev, Dmitry; Blakeslee, John P.; Blanton, Michael R.; Bochanski, John J.; Boroski, William N.; Brewington, Howard J.; Brinchmann, Jarle; Brinkmann, J.; Brunner, Robert J.; Budavári, Tamás; Carey, Larry N.; Carliles, Samuel; Carr, Michael A.; Castander, Francisco J.; Cinabro, David; Connolly, A. J.; Csabai, István; Cunha, Carlos E.; Czarapata, Paul C.; Davenport, James R. A.; de Haas, Ernst; Dilday, Ben; Doi, Mamoru; Eisenstein, Daniel J.; Evans, Michael L.; Evans, N. W.; Fan, Xiaohui; Friedman, Scott D.; Frieman, Joshua A.; Fukugita, Masataka; Gänsicke, Boris T.; Gates, Evalyn; Gillespie, Bruce; Gilmore, G.; Gonzalez, Belinda; Gonzalez, Carlos F.; Grebel, Eva K.; Gunn, James E.; Györy, Zsuzsanna; Hall, Patrick B.; Harding, Paul; Harris, Frederick H.; Harvanek, Michael; Hawley, Suzanne L.; Hayes, Jeffrey J. E.; Heckman, Timothy M.; Hendry, John S.; Hennessy, Gregory S.; Hindsley, Robert B.; Hoblitt, J.; Hogan, Craig J.; Hogg, David W.; Holtzman, Jon A.; Hyde, Joseph B.; Ichikawa, Shin-ichi; Ichikawa, Takashi; Im, Myungshin; Ivezić, Željko; Jester, Sebastian; Jiang, Linhua; Johnson, Jennifer A.; Jorgensen, Anders M.; Jurić, Mario; Kent, Stephen M.; Kessler, R.; Kleinman, S. J.; Knapp, G. R.; Konishi, Kohki; Kron, Richard G.; Krzesinski, Jurek; Kuropatkin, Nikolay; Lampeitl, Hubert; Lebedeva, Svetlana; Lee, Myung Gyoon; Lee, Young Sun; French Leger, R.; Lépine, Sébastien; Li, Nolan; Lima, Marcos; Lin, Huan; Long, Daniel C.; Loomis, Craig P.; Loveday, Jon; Lupton, Robert H.; Magnier, Eugene; Malanushenko, Olena; Malanushenko, Viktor; Mandelbaum, Rachel; Margon, Bruce; Marriner, John P.; Martínez-Delgado, David; Matsubara, Takahiko; McGehee, Peregrine M.; McKay, Timothy A.; Meiksin, Avery; Morrison, Heather L.; Mullally, Fergal; Munn, Jeffrey A.; Murphy, Tara; Nash, Thomas; Nebot, Ada; Neilsen, Eric H., Jr.; Newberg, Heidi Jo; Newman, Peter R.; Nichol, Robert C.; Nicinski, Tom; Nieto-Santisteban, Maria; Nitta, Atsuko; Okamura, Sadanori; Oravetz, Daniel J.; Ostriker, Jeremiah P.; Owen, Russell; Padmanabhan, Nikhil; Pan, Kaike; Park, Changbom; Pauls, George; Peoples, John, Jr.; Percival, Will J.; Pier, Jeffrey R.; Pope, Adrian C.; Pourbaix, Dimitri; Price, Paul A.; Purger, Norbert; Quinn, Thomas; Raddick, M. Jordan; Re Fiorentin, Paola; Richards, Gordon T.; Richmond, Michael W.; Riess, Adam G.; Rix, Hans-Walter; Rockosi, Constance M.; Sako, Masao; Schlegel, David J.; Schneider, Donald P.; Scholz, Ralf-Dieter; Schreiber, Matthias R.; Schwope, Axel D.; Seljak, Uroš; Sesar, Branimir; Sheldon, Erin; Shimasaku, Kazu; Sibley, Valena C.; Simmons, A. E.; Sivarani, Thirupathi; Allyn Smith, J.; Smith, Martin C.; Smolčić, Vernesa; Snedden, Stephanie A.; Stebbins, Albert; Steinmetz, Matthias; Stoughton, Chris; Strauss, Michael A.; SubbaRao, Mark; Suto, Yasushi; Szalay, Alexander S.; Szapudi, István; Szkody, Paula; Tanaka, Masayuki; Tegmark, Max; Teodoro, Luis F. A.; Thakar, Aniruddha R.; Tremonti, Christy A.; Tucker, Douglas L.; Uomoto, Alan; Vanden Berk, Daniel E.; Vandenberg, Jan; Vidrih, S.; Vogeley, Michael S.; Voges, Wolfgang; Vogt, Nicole P.; Wadadekar, Yogesh; Watters, Shannon; Weinberg, David H.; West, Andrew A.; White, Simon D. M.; Wilhite, Brian C.; Wonders, Alainna C.; Yanny, Brian; Yocum, D. R.; York, Donald G.; Zehavi, Idit; Zibetti, Stefano; Zucker, Daniel B. Bibcode: 2009ApJS..182..543A Altcode: 2008arXiv0812.0649A This paper describes the Seventh Data Release of the Sloan Digital Sky Survey (SDSS), marking the completion of the original goals of the SDSS and the end of the phase known as SDSS-II. It includes 11,663 deg2 of imaging data, with most of the ~2000 deg2 increment over the previous data release lying in regions of low Galactic latitude. The catalog contains five-band photometry for 357 million distinct objects. The survey also includes repeat photometry on a 120° long, 2fdg5 wide stripe along the celestial equator in the Southern Galactic Cap, with some regions covered by as many as 90 individual imaging runs. We include a co-addition of the best of these data, going roughly 2 mag fainter than the main survey over 250 deg2. The survey has completed spectroscopy over 9380 deg2 the spectroscopy is now complete over a large contiguous area of the Northern Galactic Cap, closing the gap that was present in previous data releases. There are over 1.6 million spectra in total, including 930,000 galaxies, 120,000 quasars, and 460,000 stars. The data release includes improved stellar photometry at low Galactic latitude. The astrometry has all been recalibrated with the second version of the USNO CCD Astrograph Catalog, reducing the rms statistical errors at the bright end to 45 milliarcseconds per coordinate. We further quantify a systematic error in bright galaxy photometry due to poor sky determination; this problem is less severe than previously reported for the majority of galaxies. Finally, we describe a series of improvements to the spectroscopic reductions, including better flat fielding and improved wavelength calibration at the blue end, better processing of objects with extremely strong narrow emission lines, and an improved determination of stellar metallicities. Title: Using magnetic activity and Galactic dynamics to constrain the ages of M dwarfs Authors: West, Andrew A.; Hawley, Suzanne L.; Bochanski, John J.; Covey, Kevin R.; Burgasser, Adam J. Bibcode: 2009IAUS..258..327W Altcode: 2008arXiv0812.1223W We present a study of the dynamics and magnetic activity of M dwarfs using the largest spectroscopic sample of low-mass stars ever assembled. The age at which strong surface magnetic activity (as traced by Hα) ceases in M dwarfs has been inferred to have a strong dependence on mass (spectral type, surface temperature) and explains previous results showing a large increase in the fraction of active stars at later spectral types. Using spectral observations of more than 40000 M dwarfs from the Sloan Digital Sky Survey, we show that the fraction of active stars decreases as a function of vertical distance from the Galactic plane (a statistical proxy for age), and that the magnitude of this decrease changes significantly for different M spectral types. Adopting a simple dynamical model for thin disk vertical heating, we assign an age for the activity decline at each spectral type, and thus determine the activity lifetimes for M dwarfs. In addition, we derive a statistical age-activity relation for each spectral type using the dynamical model, the vertical distance from the Plane and the Hα emission line luminosity of each star (the latter of which also decreases with vertical height above the Galactic plane). Title: Short Period Variability Of An M-dwarf In SDSS Stripe-82 Authors: Munshi, Ferah; Becker, A.; Hawley, S. L.; Bochanski, J. J.; Sesar, B.; Kowalski, A. Bibcode: 2009AAS...21443007M Altcode: We present analysis of a unique short-period object selected from the SDSS-II Stripe 82 photometric time-domain database. This object stands out in color-period space, having the colors and spectrum of an early M-dwarf (M0-M1) but a photometric period of 0.1 days, an amplitude of 0.2 magnitudes, and a sinusoidal lightcurve. It is unusual to find

such a red object with such a short period. We have obtained multiple epochs of spectroscopy with the MAGE spectrograph at Magellan to constrain any radial velocity variations. We examine the possible

interpretations of this system, including : an M-dwarf/M-dwarf eclipsing system, which would be near the Algol limit; stellar rotation with persistent star spots; and stellar pulsation. Title: X-Ray-Emitting Stars Identified from the ROSAT All-Sky Survey and the Sloan Digital Sky Survey Authors: Agüeros, Marcel A.; Anderson, Scott F.; Covey, Kevin R.; Hawley, Suzanne L.; Margon, Bruce; Newsom, Emily R.; Posselt, Bettina; Silvestri, Nicole M.; Szkody, Paula; Voges, Wolfgang Bibcode: 2009ApJS..181..444A Altcode: 2009arXiv0903.4202A The ROSAT All-Sky Survey (RASS) was the first imaging X-ray survey of the entire sky. Combining the RASS Bright and Faint Source Catalogs yields an average of about three X-ray sources per square degree. However, while X-ray source counterparts are known to range from distant quasars to nearby M dwarfs, the RASS data alone are often insufficient to determine the nature of an X-ray source. As a result, large-scale follow-up programs are required to construct samples of known X-ray emitters. We use optical data produced by the Sloan Digital Sky Survey (SDSS) to identify 709 stellar X-ray emitters cataloged in the RASS and falling within the SDSS Data Release 1 footprint. Most of these are bright stars with coronal X-ray emission unsuitable for SDSS spectroscopy, which is designed for fainter objects (g > 15 [mag]). Instead, we use SDSS photometry, correlations with the Two Micron All Sky Survey and other catalogs, and spectroscopy from the Apache Point Observatory 3.5 m telescope to identify these stellar X-ray counterparts. Our sample of 707 X-ray-emitting F, G, K, and M stars is one of the largest X-ray-selected samples of such stars. We derive distances to these stars using photometric parallax relations appropriate for dwarfs on the main sequence, and use these distances to calculate LX . We also identify a previously unknown cataclysmic variable (CV) as a RASS counterpart. Separately, we use correlations of the RASS and the SDSS spectroscopic catalogs of CVs and white dwarfs (WDs) to study the properties of these rarer X-ray-emitting stars. We examine the relationship between (fX /fg ) and the equivalent width of the Hβ emission line for 46 X-ray-emitting CVs and discuss tentative classifications for a subset based on these quantities. We identify 17 new X-ray-emitting DA (hydrogen) WDs, of which three are newly identified WDs. We report on follow-up observations of three candidate cool X-ray-emitting WDs (one DA and two DB (helium) WDs); we have not confirmed X-ray emission from these WDs.

Includes observations obtained with the Apache Point Observatory 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium. Title: Observations and Models of Quiescent M Dwarf Chromospheres Authors: Walkowicz, Lucianne M.; Hawley, Suzanne L. Bibcode: 2009AIPC.1094..696W Altcode: 2009csss...15..696W Using simultaneous observations of the Hα and Ca II K lines for a sample of M3 dwarfs, we investigate the temperature structure required to produce the spectral signatures of chromospheric activity in low mass stars. Combined, the Hα and Ca II K data provide a rich set of observational challenges to theory. We apply these data as empirical constraints for new static models of quiescent M dwarf atmospheres. Using these models, we find that single component model atmospheres are able to provide a satisfactory description of weakly active M dwarfs, but more active stars require two component models, with different temperature structures for active and basal regions of the chromosphere. Title: M Dwarf Flares from Time-Resolved SDSS Spectra Authors: Hilton, Eric J.; Hawley, Suzanne; West, Andrew A.; Kowalski, Adam Bibcode: 2009AIPC.1094..652H Altcode: 2009csss...15..652H Flares on low-mass dwarfs are a major source of variability in the optical and UV in the Galaxy. In addition to being a source of optical transients, these flares may have an important effect on the habitability of planets orbiting low-mass dwarfs. We present a study of flares on M dwarfs determined from Sloan Digital Sky Survey time-resolved spectra. Our sample consists of tens of thousands of M dwarfs whose SDSS spectra were formed from co-adds of several (typically 3-5) consecutive shorter (typically 9-15 minute) exposures. We present the Flare Line Index as a way to identify flares in these individual component spectra with crude time-resolution, and investigate the short-term variability of the Balmer and Ca II emission lines. Title: Tracers of Chromospheric Structure. I. Observations of Ca II K and Hα in M Dwarfs Authors: Walkowicz, Lucianne M.; Hawley, Suzanne L. Bibcode: 2009AJ....137.3297W Altcode: 2008arXiv0811.1778W We report on our observing program4This paper is based on observations obtained with the Apache Point Observatory 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. to capture simultaneous spectra of Ca II and Balmer lines in a sample of nearby M3 dwarfs. Our goal is to investigate the chromospheric temperature structure required to produce these lines at the observed levels. We find a strong positive correlation between instantaneous measurements of Ca II K and the Balmer lines in active stars, although these lines may not be positively correlated in time-resolved measurements. The relationship between Hα and Ca II K remains ambiguous for weak and intermediate activity stars, with Hα absorption corresponding to a range of Ca II K emission. A similar relationship is also observed between Ca II K and the higher-order Balmer lines. As our sample consists of a single spectral type, correlations between these important chromospheric tracers cannot be ascribed to continuum effects, as suggested by other authors. These data confirm prior nonsimultaneous observations of the Hα line behavior with increasing activity, showing an initial increase in the Hα absorption with increasing Ca II K emission, prior to Hα filling in and eventually becoming a pure emission line in the most active stars. We also compare our optical measurements with archival UV and X-ray measurements, finding a positive correlation between the chromospheric and coronal emission for both high and intermediate activity stars. We compare our results with previous determinations of the active fraction of low-mass stars, and discuss them in the context of surface inhomogeneity. Lastly, we discuss the application of these data as empirical constraints on new static models of quiescent M dwarf atmospheres. Title: Our Nearest 15 Million Neighbors: The Field Low-Mass Stellar Luminosity and Mass Functions Authors: Bochanski, John J.; Hawley, Suzanne L.; Reid, I. Neill; Covey, Kevin R.; West, Andrew A.; Golimowski, David A.; Ivezić, Željko Bibcode: 2009AIPC.1094..977B Altcode: 2008arXiv0810.2343B; 2009csss...15..977B We report on a new measurement of the luminosity function (LF) and mass function (MF) of field low-mass dwarfs using Sloan Digital Sky Survey (SDSS) photometry. The final catalog is composed of ~15 million low-mass stars (0.1 Msolar<M<0.8 Msolar), spread over 8,400 square degrees. Distances to the stars are estimated using new photometric parallax relations, constructed from ugriz photometry of nearby low-mass stars with trigonometric parallaxes. The LF is measured with a novel technique, which simultaneously measures Galactic structure and the stellar LF. The resulting LF is compared to previous studies and converted to a MF. The MF is well-described by a log-normal distribution, with M° = 0.27 Msolar. Title: On-sky Commissioning and Early Results from the SDSS-III-MARVELS Planet Search Authors: Lee, Brian L.; Ge, J.; Mahadevan, S.; Fleming, S. W.; Wan, X.; Groot, J.; Zhao, B.; Hearty, F.; Chang, L.; Varosi, F.; Hanna, K.; Liu, J.; van Eyken, J. C.; Guo, P.; Malik, M.; Shelden, A.; Sivarani, T.; De Lee, N.; Kane, S. R.; Wang, J.; Costello, E.; Rohan, P.; Fletcher, A.; Ford, E. B.; Agol, E.; Bochanski, J. J.; Ford, H.; Gaudi, B. S.; Holtzman, J. A.; Schneider, D. P.; Seager, S.; Weinberg, D. H.; Eisenstein, D. J.; Hawley, S. L. Bibcode: 2009AAS...21340506L Altcode: 2009BAAS...41..198L The Multi-object APO Radial Velocity Large-area Survey (MARVELS) commenced operations as an SDSS-III bright-time survey in Sep. 2008. MARVELS will be used to monitor 11000 stars for RV variations during SDSS-III, using time baselines of 1.5 years, to <10-30m/s radial velocity (RV) precision for stars with brightnesses 7.6<V<12. The first MARVELS instrument is a dispersed fixed-delay interferometer (DFDI) with a 60-object fibre-fed input, mounted at the ARC 2.5-m telescope at Apache Point Observatory. Both interferometer output beams are recorded, producing fringing spectra over wavelengths 500-570nm with resolving power R 12000. The instrument is environmentally stabilized such that no iodine cell is needed in the stellar beam path, and instrument drift calibrations are simply taken before and after each stellar exposure.

We outline our DFDI RV data reduction procedure and show calibration lamp image stability equivalent to 3m/s RMS stellar RV precision. On-sky, even in the presence of higher than normal environmental disturbances during our Sep. commissioning observations, our first preliminary analysis achieved 12m/s RMS RV precision (on 9m/s photon noise) on the RV-stable star HD 9407 (V=6.5) in 144 sec. exposures, and 30m/s RMS RV precision (on 20m/s photon noise) on the known planet-bearing star TrES-2 (V=11.4) in 40-60 min. exposures, over 6 commissioning nights. Finally, we show candidate radial velocity variables garnered after moving to normal survey operations during Oct.-Dec. 2008, acquired using an operations strategy designed to deliver optimum extrasolar planet yield over the six-year lifecycle of SDSS-III.

We would like to thank the W.M. Keck Foundation, Sloan Foundation, NSF, NASA and UF for support. Title: Flare Rates on M Dwarfs: Observing Program Authors: Hilton, Eric J.; Hawley, S.; Ule, N.; Kowalski, A.; Gomez, T.; Grammer, S.; Holtzman, J.; Huang, M.; Huehnerhoff, J.; Morgan, D. Bibcode: 2009AAS...21343416H Altcode: 2009BAAS...41..305H Determining the magnitude and rate at which low mass stars flare is an important problem in stellar astrophysics because flares are a major source of variability in large time domain surveys, affect the atmospheres of orbiting planetary systems, and are manifestations of magnetic field production and reconfiguration, processes which are not well understood on M dwarfs. We present early results from a multi-year observing campaign to statistically determine M dwarf flare rates and energies as a function of spectral type and activity level. Our observations consist of over 100 hours of monitoring M dwarfs on three telescopes. In addition to preliminary flare rates, we discuss our method of determining energy and duration. Title: The Sdss-iii Multi-object Apo Radial-velocity Exoplanet Large-area Survey (marvels) And Its Early Results Authors: Ge, Jian; Lee, B.; Mahadevan, S.; Wan, X.; Groot, J.; Zhao, B.; Hearty, F.; Fleming, S.; van Eyken, J.; Hanna, K.; Varosi, F.; Chang, L.; Thirupathi, S.; Chen, Z.; Shelden, A.; Liu, J.; De Lee, N.; Malik, M.; Rohan, P.; Kane, S.; Guo, P.; Leger, F.; Wang, J.; Ford, E. B.; Agol, E.; Gaudi, S.; Ford, H.; Schneider, D.; Holtzman, J.; Harding, P.; Blanton, M.; Snedden, S.; Pan, K.; Fletcher, A.; Costello, E.; Bochanski, J.; Seager, S.; Weinberg, D.; Eisenstein, D.; Gunn, J.; Hawley, S. Bibcode: 2009AAS...21333602G Altcode: 2009BAAS...41..397G MARVELS, as one of the four on-going Sloan Digital Sky Survey (SDSS) III survey projects, is conducting the largest ground-based radial velocity planet survey using a next-generation, multiple-object , dispersed fixed-delay interferometer Doppler instrument in 2008-2014. Over the next six years, MARVELS plans on monitoring a total of 11,000 late F, G and K stars (90% main sequence and subgiants; 10% giant stars) with V magnitude 7.6-12 over $\sim$800 square degrees. The survey aims to detect and characterize a single large, statistically well defined sample of hundreds of new giant planets with periods ? days orbiting host stars with well-understood selection biases. The first MARVELS instrument with 60 object capability was commissioned at the SDSS telescope at Apache Point Observatory in September 2008 and will be used to conduct the science survey starting in October 2008. The early commissioning results show that the instrument has reached about 6mK (peak-to-valley) long-term thermal stability, 2-3 m/s Doppler precision with bright calibration light sources, and 20 m/s photon noise error for TrES-2 (a V=11.4 G0V star) in a 40 min exposure. The early science results and instrument performance from the first three months of operation will be reported.

We would like to thank the W.M. Keck Foundation, Sloan Foundation, NSF, NASA and UF for support. Title: The Time-Dependent Effect of a Stellar Flare on Terrestrial Planet Habitability and Biosignatures Authors: Walkowicz, Lucianne M.; Segura, A.; Meadows, V.; Kasting, J.; Hawley, S. Bibcode: 2009AAS...21342802W Altcode: 2009BAAS...41..259W Due to their low stellar luminosities, M dwarf habitable zones (as defined by Kasting et al. 1993) lie very near the star ( 0.2 AU or less), making planets in the habitable zone especially vulnerable to the effects of stellar activity. Although M dwarfs emit the bulk of their flux in the optical and near infrared, activity on these stars produces energetic radiation, from X rays to ultraviolet (UV), that may be dangerous for life on a planet in the habitable zone (HZ) of the star. In particular, stellar activity is a concern for the continuity of habitability on the planetary surface, as starspots or flares may cause the stellar irradiance to vary strongly with time.

Using a convective/radiative model coupled to a photochemical model, we simulated the atmosphere of an Earth-like planet located in the habitable zone of the active M dwarf AD Leo over the course of a large flare. We present the time-dependent atmospheric temperature and composition profiles for water, methane and ozone, finding that while water and ozone are photolyzed in the stratosphere, the temperature profile and methane column depth are relatively unperturbed. Ozone number density decreases in the stratosphere during the impulsive phase of the flare, but quickly recovers to preflare levels thereafter. While the UV flux at the planetary surface changes with the ozone concentration during the flare, we find that the planetary surface UV flux is less than that received on Earth's surface except during the very peak of the flare. We conclude that even large flares may not be detrimental to life on planets with Earth-like atmospheres. Title: Statement from ACCORD for ASTRO2010 Authors: Alcock, Charles; Bolte, Michael; Freedman, Wendy; Kudritzki, Rolf-Peter; Kulkarni, Shri; Martin, Pierre; Smith, William; Strittmatter, Peter; Hawley, Suzanne Bibcode: 2009astro2010P..27A Altcode: 2009astro2010P..27K No abstract at ADS Title: M Dwarf Flare Rate Analysis of SDSS Stripe 82 Authors: Kowalski, Adam; Hawley, S. L.; Hilton, E. J.; Becker, A. C.; Bochanski, J. J.; West, A. A. Bibcode: 2009AAS...21343402K Altcode: 2009BAAS...41..303K M dwarfs produce intense flares from the X-ray to the radio, including the optical by a physical mechanism which is still poorly understood. Since M dwarfs comprise about 70% of the stars in the Galaxy, their flares will be a significant source of optical transients in future time domain surveys, such as LSST, Pan-STARRS, and GAIA. Using a Flare Index to select flaring events from 40,000 low-cadence M dwarf light curves, we present the flaring rate as a function of intrinsic stellar properties, such as spectral type, level of magnetic activity, and distance from the Galactic plane. We also discuss our results in light of our understanding of flare physics and how our derived flaring rates and luminosities compare to the Lacy, Moffett, & Evans (1976) classical study of nearby active flare stars. Title: χ Values for Blue Emission Lines in M Dwarfs Authors: West, Andrew A.; Hawley, Suzanne L. Bibcode: 2008PASP..120.1161W Altcode: 2008arXiv0812.1221W We compute χ values for blue emission lines in active M dwarfs. Using flux-calibrated spectra from nearby M dwarfs and spectral M dwarf templates from SDSS, we derive analytical relations that describe how the χ values for the Ca II H and K as well as the Hβ, Hγ, Hδ, Hɛ, and H8 Balmer emission lines vary as a function of spectral type and color. These derived values are important for numerous M dwarf studies where the intrinsic luminosity of emission lines cannot be estimated due to uncertain distances and/or non-flux-calibrated spectra. We use these results to estimate the mean properties of blue emission lines in active-field M dwarfs from SDSS. Title: The Luminosity and Mass Functions of Low-Mass Stars in the Galactic Disk. I. The Calibration Region Authors: Covey, Kevin R.; Hawley, Suzanne L.; Bochanski, John J.; West, Andrew A.; Reid, I. Neill; Golimowski, David A.; Davenport, James R. A.; Henry, Todd; Uomoto, Alan; Holtzman, Jon A. Bibcode: 2008AJ....136.1778C Altcode: 2008arXiv0807.2452C We present measurements of the luminosity and mass functions of low-mass stars constructed from a catalog of matched Sloan Digital Sky Survey (SDSS) and Two Micron All Sky Survey (2MASS) detections. This photometric catalog contains more than 25,000 matched SDSS and 2MASS point sources spanning ~30 deg2 on the sky. We have obtained follow-up spectroscopy, complete to J = 16, of more than 500 low-mass dwarf candidates within a 1 deg2 subsample, and thousands of additional dwarf candidates in the remaining 29 deg2. This spectroscopic sample verifies that the photometric sample is complete, uncontaminated, and unbiased at the 99% level globally, and at the 95% level in each color range. We use this sample to derive the luminosity and mass functions of low-mass stars over nearly a decade in mass (0.7 M sun > M * > 0.1 M sun). The luminosity function of the Galactic disk is statistically consistent with that measured from volume-complete samples in the solar neighborhood. We find that the logarithmically binned mass function is best fit with an Mc = 0.29 log-normal distribution, with a 90% confidence interval of Mc = 0.20-0.50. These 90% confidence intervals correspond to linearly binned mass functions peaking between 0.27 M sun and 0.12 M sun, where the best fit MF turns over at 0.17 M sun. A power-law fit to the entire mass range sampled here, however, returns a best fit of α = 1.1 (where the Salpeter slope is α = 2.35); a broken power law returns α = 2.04 at masses greater than log M = -0.5 (M = 0.32 M sun), and α = 0.2 at lower masses. These results agree well with most previous investigations, though differences in the analytic formalisms adopted to describe those mass functions, as well as the range over which the data are fit, can give the false impression of disagreement. Given the richness of modern-day astronomical data sets, we are entering the regime whereby stronger conclusions can be drawn by comparing the actual datapoints measured in different mass functions, rather than the results of analytic analyses that impose structure on the data a priori. Having validated this method to generate a low-mass luminosity function from matched SDSS/2MASS data sets, future studies will extend this technique to the entirety of the SDSS footprint.

Based in part on observations obtained with the Apache Point Observatory 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium. Title: The Properties of Long-Period Variables in the Large Magellanic Cloud from MACHO Authors: Fraser, Oliver J.; Hawley, Suzanne L.; Cook, Kem H. Bibcode: 2008AJ....136.1242F Altcode: 2008arXiv0808.1737F We present a new analysis of the long-period variables in the Large Magellanic Cloud (LMC) from the MACHO Variable Star Catalog. Three-quarters of our sample of evolved, variable stars have periodic light curves. We characterize the stars in our sample using the multiple periods found in their frequency spectra. Additionally, we use single-epoch Two Micron All Sky Survey measurements to construct the average infrared light curves for different groups of these stars. Comparison with evolutionary models shows that stars on the red giant branch (RGB) or the early asymptotic giant branch (AGB) often show non-periodic variability, but begin to pulsate with periods on the two shortest period-luminosity (P-L) sequences (3 & 4) when they brighten to K s ≈ 13. The stars on the thermally pulsing AGB are more likely to pulsate with longer periods that lie on the next two P-L sequences (1 & 2), including the sequence associated with the Miras in the LMC. The Petersen diagram and its variants show that multi-periodic stars on each pair of these sequences (3 & 4, and 1 & 2) typically pulsate with periods associated only with that pair. The periods in these multi-periodic stars become longer and stronger as the star evolves. We further constrain the mechanism behind the long secondary periods (LSPs) seen in half of our sample, and find that there is a close match between the luminosity functions of the LSP stars and all of the stars in our sample, and that these star's pulsation amplitudes are relatively wavelength independent. Although this is characteristic of stellar multiplicity, the large number of these variables is problematic for that explanation. Title: The Milky Way Tomography with SDSS. II. Stellar Metallicity Authors: Ivezić, Željko; Sesar, Branimir; Jurić, Mario; Bond, Nicholas; Dalcanton, Julianne; Rockosi, Constance M.; Yanny, Brian; Newberg, Heidi J.; Beers, Timothy C.; Allende Prieto, Carlos; Wilhelm, Ron; Lee, Young Sun; Sivarani, Thirupathi; Norris, John E.; Bailer-Jones, Coryn A. L.; Re Fiorentin, Paola; Schlegel, David; Uomoto, Alan; Lupton, Robert H.; Knapp, Gillian R.; Gunn, James E.; Covey, Kevin R.; Allyn Smith, J.; Miknaitis, Gajus; Doi, Mamoru; Tanaka, Masayuki; Fukugita, Masataka; Kent, Steve; Finkbeiner, Douglas; Munn, Jeffrey A.; Pier, Jeffrey R.; Quinn, Tom; Hawley, Suzanne; Anderson, Scott; Kiuchi, Furea; Chen, Alex; Bushong, James; Sohi, Harkirat; Haggard, Daryl; Kimball, Amy; Barentine, John; Brewington, Howard; Harvanek, Mike; Kleinman, Scott; Krzesinski, Jurek; Long, Dan; Nitta, Atsuko; Snedden, Stephanie; Lee, Brian; Harris, Hugh; Brinkmann, Jonathan; Schneider, Donald P.; York, Donald G. Bibcode: 2008ApJ...684..287I Altcode: 2008arXiv0804.3850I Using effective temperature and metallicity derived from SDSS spectra for ~60,000 F- and G-type main-sequence stars (0.2 < g - r < 0.6), we develop polynomial models for estimating these parameters from the SDSS u - g and g - r colors. These photometric estimates have similar error properties as those determined from SDSS spectra. We apply this method to SDSS photometric data for over 2 million F/G stars and measure the unbiased metallicity distribution for a complete volume-limited sample of stars at distances between 500 pc and 8 kpc. The metallicity distribution can be exquisitely modeled using two components with a spatially varying number ratio, which correspond to disk and halo. The two components also possess the kinematics expected for disk and halo stars. The metallicity of the halo component is spatially invariant, while the median disk metallicity smoothly decreases with distance from the Galactic plane from -0.6 at 500 pc to -0.8 beyond several kiloparsecs. The absence of a correlation between metallicity and kinematics for disk stars is in a conflict with the traditional decomposition in terms of thin and thick disks. We detect coherent substructures in the kinematics-metallicity space, such as the Monoceros stream, which rotates faster than the LSR, and has a median metallicity of [Fe/H] = -0.95, with an rms scatter of only ~0.15 dex. We extrapolate our results to the performance expected from the Large Synoptic Survey Telescope (LSST) and estimate that LSST will obtain metallicity measurements accurate to 0.2 dex or better, with proper-motion measurements accurate to ~0.5 mas yr-1, for about 200 million F/G dwarf stars within a distance limit of ~100 kpc (g < 23.5). Title: Evidence for Distinct Components of the Galactic Stellar Halo from 838 RR Lyrae Stars Discovered in the LONEOS-I Survey Authors: Miceli, Antonino; Rest, Armin; Stubbs, Christopher W.; Hawley, Suzanne L.; Cook, Kem H.; Magnier, Eugene A.; Krisciunas, Kevin; Bowell, Edward; Koehn, Bruce Bibcode: 2008ApJ...678..865M Altcode: 2007arXiv0706.1583M We present 838 ab-type RR Lyrae stars from the Lowell Observatory Near Earth Objects Survey Phase I (LONEOS-I). These objects cover 1430 deg2 and span distances ranging from 3 to 30 kpc from the Galactic center. Object selection is based on phased, photometric data with 28-50 epochs. We use this large sample to explore the bulk properties of the stellar halo, including the spatial distribution. The period-amplitude distribution of this sample shows that the majority of these RR Lyrae stars resemble Oosterhoff type I, but there is a significant fraction (26%) which have longer periods and appear to be Oosterhoff type II. We find that the radial distributions of these two populations have significantly different profiles (ρOoI ~ R-2.26 +/- 0.07 and ρOoII ~ R-2.88 +/- 0.11). This suggests that the stellar halo was formed by at least two distinct accretion processes and supports dual-halo models. Title: Characterizing the Near-UV Environment of M Dwarfs Authors: Walkowicz, Lucianne M.; Johns-Krull, Christopher M.; Hawley, Suzanne L. Bibcode: 2008ApJ...677..593W Altcode: 2007arXiv0711.1861W We report the results of our Hubble Space Telescope (HST) snapshot survey with the ACS HRC PR200L prism, designed to measure the near-UV emission in a sample of nearby M dwarfs. Thirty-three stars were observed, spanning the mass range from 0.1 to 0.6 solar masses (Teff ~ 2200-4000 K) where the UV energy distributions vary widely between active and inactive stars. These observations provide much needed constraints on models of the habitability zone and the atmospheres of possible terrestrial planets orbiting M dwarf hosts and will be useful in refining the target selection for future space missions such as Terrestrial Planet Finder (TPF). We compare our data with a new generation of M dwarf atmospheric models and discuss their implications for the chromospheric energy budget. These NUV data will also be valuable in conjunction with existing optical, FUV, and X-ray data to explore unanswered questions regarding the dynamo generation and magnetic heating in low-mass stars. Title: The Sixth Data Release of the Sloan Digital Sky Survey Authors: Adelman-McCarthy, Jennifer K.; Agüeros, Marcel A.; Allam, Sahar S.; Allende Prieto, Carlos; Anderson, Kurt S. J.; Anderson, Scott F.; Annis, James; Bahcall, Neta A.; Bailer-Jones, C. A. L.; Baldry, Ivan K.; Barentine, J. C.; Bassett, Bruce A.; Becker, Andrew C.; Beers, Timothy C.; Bell, Eric F.; Berlind, Andreas A.; Bernardi, Mariangela; Blanton, Michael R.; Bochanski, John J.; Boroski, William N.; Brinchmann, Jarle; Brinkmann, J.; Brunner, Robert J.; Budavári, Tamás; Carliles, Samuel; Carr, Michael A.; Castander, Francisco J.; Cinabro, David; Cool, R. J.; Covey, Kevin R.; Csabai, István; Cunha, Carlos E.; Davenport, James R. A.; Dilday, Ben; Doi, Mamoru; Eisenstein, Daniel J.; Evans, Michael L.; Fan, Xiaohui; Finkbeiner, Douglas P.; Friedman, Scott D.; Frieman, Joshua A.; Fukugita, Masataka; Gänsicke, Boris T.; Gates, Evalyn; Gillespie, Bruce; Glazebrook, Karl; Gray, Jim; Grebel, Eva K.; Gunn, James E.; Gurbani, Vijay K.; Hall, Patrick B.; Harding, Paul; Harvanek, Michael; Hawley, Suzanne L.; Hayes, Jeffrey; Heckman, Timothy M.; Hendry, John S.; Hindsley, Robert B.; Hirata, Christopher M.; Hogan, Craig J.; Hogg, David W.; Hyde, Joseph B.; Ichikawa, Shin-ichi; Ivezić, Željko; Jester, Sebastian; Johnson, Jennifer A.; Jorgensen, Anders M.; Jurić, Mario; Kent, Stephen M.; Kessler, R.; Kleinman, S. J.; Knapp, G. R.; Kron, Richard G.; Krzesinski, Jurek; Kuropatkin, Nikolay; Lamb, Donald Q.; Lampeitl, Hubert; Lebedeva, Svetlana; Lee, Young Sun; French Leger, R.; Lépine, Sébastien; Lima, Marcos; Lin, Huan; Long, Daniel C.; Loomis, Craig P.; Loveday, Jon; Lupton, Robert H.; Malanushenko, Olena; Malanushenko, Viktor; Mandelbaum, Rachel; Margon, Bruce; Marriner, John P.; Martínez-Delgado, David; Matsubara, Takahiko; McGehee, Peregrine M.; McKay, Timothy A.; Meiksin, Avery; Morrison, Heather L.; Munn, Jeffrey A.; Nakajima, Reiko; Neilsen, Eric H., Jr.; Newberg, Heidi Jo; Nichol, Robert C.; Nicinski, Tom; Nieto-Santisteban, Maria; Nitta, Atsuko; Okamura, Sadanori; Owen, Russell; Oyaizu, Hiroaki; Padmanabhan, Nikhil; Pan, Kaike; Park, Changbom; Peoples, John, Jr.; Pier, Jeffrey R.; Pope, Adrian C.; Purger, Norbert; Raddick, M. Jordan; Re Fiorentin, Paola; Richards, Gordon T.; Richmond, Michael W.; Riess, Adam G.; Rix, Hans-Walter; Rockosi, Constance M.; Sako, Masao; Schlegel, David J.; Schneider, Donald P.; Schreiber, Matthias R.; Schwope, Axel D.; Seljak, Uroš; Sesar, Branimir; Sheldon, Erin; Shimasaku, Kazu; Sivarani, Thirupathi; Allyn Smith, J.; Snedden, Stephanie A.; Steinmetz, Matthias; Strauss, Michael A.; SubbaRao, Mark; Suto, Yasushi; Szalay, Alexander S.; Szapudi, István; Szkody, Paula; Tegmark, Max; Thakar, Aniruddha R.; Tremonti, Christy A.; Tucker, Douglas L.; Uomoto, Alan; Vanden Berk, Daniel E.; Vandenberg, Jan; Vidrih, S.; Vogeley, Michael S.; Voges, Wolfgang; Vogt, Nicole P.; Wadadekar, Yogesh; Weinberg, David H.; West, Andrew A.; White, Simon D. M.; Wilhite, Brian C.; Yanny, Brian; Yocum, D. R.; York, Donald G.; Zehavi, Idit; Zucker, Daniel B. Bibcode: 2008ApJS..175..297A Altcode: 2007arXiv0707.3413A This paper describes the Sixth Data Release of the Sloan Digital Sky Survey. With this data release, the imaging of the northern Galactic cap is now complete. The survey contains images and parameters of roughly 287 million objects over 9583 deg2, including scans over a large range of Galactic latitudes and longitudes. The survey also includes 1.27 million spectra of stars, galaxies, quasars, and blank sky (for sky subtraction) selected over 7425 deg2. This release includes much more stellar spectroscopy than was available in previous data releases and also includes detailed estimates of stellar temperatures, gravities, and metallicities. The results of improved photometric calibration are now available, with uncertainties of roughly 1% in g, r, i, and z, and 2% in u, substantially better than the uncertainties in previous data releases. The spectra in this data release have improved wavelength and flux calibration, especially in the extreme blue and extreme red, leading to the qualitatively better determination of stellar types and radial velocities. The spectrophotometric fluxes are now tied to point-spread function magnitudes of stars rather than fiber magnitudes. This gives more robust results in the presence of seeing variations, but also implies a change in the spectrophotometric scale, which is now brighter by roughly 0.35 mag. Systematic errors in the velocity dispersions of galaxies have been fixed, and the results of two independent codes for determining spectral classifications and redshifts are made available. Additional spectral outputs are made available, including calibrated spectra from individual 15 minute exposures and the sky spectrum subtracted from each exposure. We also quantify a recently recognized underestimation of the brightnesses of galaxies of large angular extent due to poor sky subtraction; the bias can exceed 0.2 mag for galaxies brighter than r = 14 mag. Title: Constraining the Age-Activity Relation for Cool Stars: The Sloan Digital Sky Survey Data Release 5 Low-Mass Star Spectroscopic Sample Authors: West, Andrew A.; Hawley, Suzanne L.; Bochanski, John J.; Covey, Kevin R.; Reid, I. Neill; Dhital, Saurav; Hilton, Eric J.; Masuda, Michael Bibcode: 2008AJ....135..785W Altcode: 2007arXiv0712.1590W We present a spectroscopic analysis of over 38,000 low-mass stars from the Sloan Digital Sky Survey (SDSS) Data Release 5 (DR5). Analysis of this unprecedentedly large sample confirms the previously detected decrease in the fraction of magnetically active stars (as traced by Hα emission) as a function of the vertical distance from the Galactic plane. The magnitude and slope of this effect vary as a function of spectral type. Using simple 1D dynamical models, we demonstrate that the drop in activity fraction can be explained by thin-disk dynamical heating and a rapid decrease in magnetic activity. The timescale for this rapid activity decrease changes according to the spectral type. By comparing our data to the simulations, we calibrate the age-activity relation at each M dwarf spectral type. We also present evidence for a possible decrease in the metallicity as a function of height above the Galactic plane. In addition to our activity analysis, we provide line measurements, molecular band indices, colors, radial velocities, 3D space motions, and mean properties as a function of spectral type for the SDSS DR5 low-mass star sample. Title: Externally Induced or Internally Produced: What is the Source of the Extreme Magnetic Activity Observed in Very Low Mass Stars? Authors: Howell, Steve B.; Giampapa, Mark; Harrison, Thomas; Hawley, Suzanne; Hill, Frank; Honeycutt, Kent; Kafka, Stella; Silvestri, Nicole; Szkody, Paula; Walter, Fred; West, Andrew Bibcode: 2008noao.prop...95H Altcode: Recent observations of the very low mass donor stars in short period interacting binaries have revealed the presence of active chromospheres. Our group has obtained initial spectra for five such systems to date and found evidence of stellar activity in all of them, including a brown dwarf mass (0.055 M-sun) donor star. The Washington group has obtained a SDSS sample of a number of close, but non-interacting white dwarf + red dwarf binaries and find H(alpha) emission related to activity. We plan to perform the first detailed phase-resolved spectroscopic study of the active chromospheres in this set of rapidly rotating (<0.3 day), low mass (<0.25 M-sun), fully convective late-type stars and brown dwarfs. Our observational goals are to study the extent, nature and short-term changes of these active chromospheres on the low mass stars of close binaries. Is the extreme activity caused by the low mass star itself or externally driven by tidal or magnetic forces? The long term goals are to complete a large enough sample (~10 systems) to provide statistically useful measurements and to use the extended time allocation to obtain long term ``coverage" spectra of each system to monitor, measure, and understand the solar-type cycles likely to be present. Title: Stellar SEDs from 0.3 to 2.5 μm: Tracing the Stellar Locus and Searching for Color Outliers in the SDSS and 2MASS Authors: Covey, K. R.; Ivezić, Ž.; Schlegel, D.; Finkbeiner, D.; Padmanabhan, N.; Lupton, R. H.; Agüeros, M. A.; Bochanski, J. J.; Hawley, S. L.; West, A. A.; Seth, A.; Kimball, A.; Gogarten, S. M.; Claire, M.; Haggard, D.; Kaib, N.; Schneider, D. P.; Sesar, B. Bibcode: 2007AJ....134.2398C Altcode: 2007arXiv0707.4473C The Sloan Digital Sky Survey (SDSS) and Two Micron All Sky Survey (2MASS) are rich resources for studying stellar astrophysics and the structure and formation history of the Galaxy. As new surveys and instruments adopt similar filter sets, it is increasingly important to understand the properties of the ugrizJHKs stellar locus, both to inform studies of "normal" main-sequence stars and enable robust searches for point sources with unusual colors. Using a sample of ~600,000 point sources detected by SDSS and 2MASS, we tabulate the position and width of the ugrizJHKs stellar locus as a function of g - i color, and provide accurate polynomial fits. We map the Morgan-Keenan spectral type sequence to the median stellar locus by using synthetic photometry of spectral standards and by analyzing 3000 SDSS stellar spectra with a custom spectral typing pipeline, described in the Appendix to this paper. We develop an algorithm to calculate a point source's minimum separation from the stellar locus in a seven-dimensional color space, and use it to robustly identify objects with unusual colors, as well as spurious SDSS/2MASS matches. Analysis of a final catalog of 2117 color outliers identifies 370 white-dwarf/M dwarf (WDMD) pairs, 93 QSOs, and 90 M giant/carbon star candidates, and demonstrates that WDMD pairs and QSOs can be distinguished on the basis of their J - Ks and r - z colors. We also identify a group of objects with correlated offsets in the u - g versus g - r and g - r versus r - i color-color spaces, but subsequent follow-up is required to reveal the nature of these objects. Future applications of this algorithm to a matched SDSS-UKIDSS catalog may well identify additional classes of objects with unusual colors by probing new areas of color-magnitude space. Title: Improved Photometric Calibrations for Red Stars Observed with the SDSS Photometric Telescope Authors: Davenport, James R. A.; Bochanski, John J.; Covey, Kevin R.; Hawley, Suzanne L.; West, Andrew A.; Schneider, Donald P. Bibcode: 2007AJ....134.2430D Altcode: 2007arXiv0708.0889D We present a new set of photometric transformations for red stars observed with the Sloan Digital Sky Survey (SDSS) 0.5 m Photometric Telescope (PT) and the SDSS 2.5 m telescope at the Apache Point Observatory in New Mexico. Nightly PT observations of US Naval Observatory standards are used to determine extinction corrections and calibration terms for SDSS 2.5 m photometry. Systematic differences between the PT and native SDSS 2.5 m ugriz photometry require conversions between the two systems which have previously been undefined for the reddest stars. By matching ~43,000 stars observed with both the PT and SDSS 2.5 m, we extend the present relations to include low-mass stars with colors 0.6 <= r - i <= 1.7. These corrections will allow us to place photometry of bright, low-mass trigonometric parallax stars previously observed with the PT on the 2.5 m system. We present new transformation equations and discuss applications of these data to future low-mass star studies using the SDSS. Title: Exploring the Local Milky Way: M Dwarfs as Tracers of Galactic Populations Authors: Bochanski, John J.; Munn, Jeffrey A.; Hawley, Suzanne L.; West, Andrew A.; Covey, Kevin R.; Schneider, Donald P. Bibcode: 2007AJ....134.2418B Altcode: 2007arXiv0708.0044B We have assembled a spectroscopic sample of low-mass dwarfs observed as part of the Sloan Digital Sky Survey along one Galactic sight line, designed to investigate the observable properties of the thin and thick disks. This sample of ~7400 K and M stars also has measured ugriz photometry, proper motions, and radial velocities. We compute UVW space-motion distributions, and investigate their structure with respect to vertical distance from the Galactic plane. We place constraints on the velocity dispersions of the thin and thick disks, using two-component Gaussian fits. We also compare these kinematic distributions to a leading Galactic model. Finally, we investigate other possible observable differences between the thin and thick disks, such as color, active fraction, and metallicity. Title: Our 3 Million Nearest Neighbors: The Field Luminosity and Mass Functions of M Dwarfs from Matched SDSS & 2MASS Observations Authors: Bochanski, John J.; Hawley, S. L.; Covey, K. R.; Reid, N.; West, A. A.; SDSS Collaboration Bibcode: 2007AAS...211.2103B Altcode: 2007BAAS...39R.772B We present the initial results of our investigation into the field luminosity and mass functions of M dwarfs. We have assembled a database of matched SDSS and 2MASS observations of 3 million low-mass stars, two orders of magnitude larger than any previous study on this topic. The observations span the entire SDSS footprint, about 8,400 square degrees. Using this 8-color photometry and improved color-absolute magnitude relations, we derive luminosities and masses for each star in our sample. We quantify the uncertainties in our analysis using results from a calibration region of 30 square degrees, where we have spectroscopic observations of several thousand stars. Additionally, we measure the structure of the local Milky Way, determining the density profiles of the thin and thick disks.

The authors gratefully acknowledge the support of NSF grant AST06-07644 and NASA ADP grant NAG5-13111. Title: Galactic M Dwarf Flare Rates Authors: Hawley, Suzanne L.; Hilton, E. J.; Kowalski, A. F.; Bochanski, J. J.; West, A. A. Bibcode: 2007AAS...21110306H Altcode: 2007BAAS...39..920H We present preliminary results from our effort to model M dwarf flare rates in the Galaxy. Using existing flare data and new determinations of the M dwarf luminosity function and activity fractions from SDSS data, we have developed numerical simulations to model the number of flares seen along a given Galactic sightline. We compare the simulations with data from the SDSS repeat scans obtained in the equatorial region. These simulations will be useful for predicting the detection of M dwarf variability in new time domain surveys such as PanSTARRs and LSST.

Based on data from the Sloan Digital Sky Survey (www.sdss.org) Title: Pulsation and Mass-Loss in Long Period Variables Authors: Fraser, Oliver J.; Hawley, S. L.; Cook, K. H. Bibcode: 2007AAS...211.2504F Altcode: 2007BAAS...39..776F We present a new analysis of the long period variables in the Large Magellanic Cloud from the MACHO Variable Star Catalog. Of our sample of 61,587 evolved stars with non-constant light curves, 80 percent have periodic light curves. We characterize these stars using the multiple periods, harmonics, and mixing terms found in their frequency spectra. Additionally, we use single-epoch 2MASS measurements to construct the average infrared light curve of each of the well-known period-luminosity sequences. We further constrain the mechanism behind the long secondary periods seen in many of these stars, and find that an explanation due to binarity is indeed likely. We describe the characteristic variability at each of the stages of RGB and AGB evolution by comparison with population synthesis models. RGB and early AGB stars vary with either periodic or chaotic pulsations, the latter explain the large number of stars (22 percent of our sample) with periods clearly due to the annual observing cycle on Earth. Stars in the thermally pulsing AGB pulsate periodically with longer periods than those earlier in their evolution, and are also the most likely to undergo heavy mass loss. We also compare the long period variables in the MACHO catalogs of the SMC and the Galactic Bulge with our results. Title: The Active Lives of M Dwarfs: The Activity, Dynamical and Metallicity Evolution of Most Milky Way Stars Authors: West, Andrew A.; Hawley, S. L.; Bochanski, J. J.; Covey, K. R.; Reid, I. N. Bibcode: 2007AAS...211.2106W Altcode: 2007BAAS...39R.772W We present the results from a study of the dynamics and magnetic activity of M dwarfs using the largest spectroscopic sample of low-mass stars ever assembled. The age at which strong surface magnetic activity ceases in M dwarfs has been inferred to have a strong dependence on mass (spectral type, surface temperature) and explains previous results showing a large increase in the fraction of active stars at later spectral types. Using spectral observations of more than 40,000 M dwarfs from the SDSS, we show that the fraction of active stars decreases as a function of vertical distance from the Galactic plane, and that the magnitude of this decrease changes significantly for different M spectral types. Adopting a simple dynamical model for thin disk vertical heating, we assign an age for the activity decline at each spectral type, and thus determine an activity-age relation for M dwarfs. These results provide constraints for dynamo models that seek to describe the production of surface magnetic fields in low mass stars. In addition, we will show how M dwarfs can be used to probe both the metallicity evolution as well as the dynamical heating and structure of the Milky Way thin disk. Title: The SDSS-III Multi-object Apo Radial-velocity Exoplanet Large-area Survey Authors: Ge, Jian; Mahadevan, S.; Lee, B.; Wan, X.; Zhao, B.; van Eyken, J.; Kane, S.; Guo, P.; Ford, E. B.; Agol, E.; Gaudi, S.; Fleming, S.; Crepp, J.; Cohen, R.; Groot, J.; Galvez, M.; Liu, J.; Ford, H.; Schneider, D.; Seager, S.; Hawley, S. L.; Weinberg, D.; Eisenstein, D. Bibcode: 2007AAS...21113209G Altcode: 2007BAAS...39..962G As part of SDSS-III survey in 2008-2014, the Multi-object APO Radial-Velocity Exoplanet Large-area Survey (MARVELS) will conduct the largest ground-based Doppler planet survey to date using the SDSS telescope and new generation multi-object Doppler instruments with 120 object capability and 10-20 m/s Doppler precision. The baseline survey plan is to monitor a total of 11,000 V=8-12 stars ( 10,000 main sequence stars and 1000 giant stars) over 800 square degrees over the 6 years. The primary goal is to produce a large, statistically well defined sample of giant planets ( 200) with a wide range of masses ( 0.2-10 Jupiter masses) and orbits (1 day-2 years) drawn from a large of host stars with a diverse set of masses, compositions, and ages for studying the diversity of extrasolar planets and constraining planet formation, migration & dynamical evolution of planetary systems. The survey data will also be used for providing a statistical sample for theoretical comparison and discovering rare systems and identifying signposts for lower-mass or more distant planets. Early science results from the pilot program will be reported.

We would like to thank the SDSS MC for allocation of the telescope time and the W.M. Keck Foundation, NSF, NASA and UF for support. Title: Self-Consistent Quiescent Model Atmospheres for M Dwarfs Authors: Walkowicz, Lucianne M.; Hawley, S. L. Bibcode: 2007AAS...211.2105W Altcode: 2007BAAS...39Q.772W H alpha and Ca II K are two of the strongest emission lines in M dwarf chromospheres, responsible for

cooling the atmosphere, balancing the magnetic heating, and determining the resulting equilibrium structure. To investigate the relationship between these two important lines, I captured simultaneous observations of Ca II K and H alpha for 85 dM3 stars of varying activity strength. The results of my observing program reveal a complex relationship between the two, where even so-called "inactive" stars (those with H alpha in absorption) may display substantial Ca II K emission. A new generation of quiescent model atmospheres is required to further investigate the chromospheric heating required to produce both of these lines at the observed levels. I present the observed results, and discuss their application as empirical constraints on static models of quiescent M dwarf atmospheres. I also present initial model calculations and place them in the context of the data. Title: The Apache Point Observatory Galactic Evolution Experiment (APOGEE) Authors: Majewski, Steven R.; Skrutskie, M. F.; Schiavon, R. P.; Wilson, J. C.; O'Connell, R. W.; Smith, V. V.; Shetrone, M.; Cunha, K.; Frinchaboy, P. M.; Reid, I. N.; Allende Prieto, C.; Eisenstein, D.; Indebetouw, R.; Nelson, M. J.; Patterson, R. J.; Rood, R. T.; Beers, T.; Bullock, J.; Crane, J. D.; Geisler, D.; Hawley, S. L.; Holtzman, J.; Johnston, K. V.; McWilliam, A.; Munn, J. A.; Spergel, D. N.; Weinberg, D.; Weinberg, M. Bibcode: 2007AAS...21113208M Altcode: 2007BAAS...39..962M APOGEE is a large-scale, NIR, high-resolution (R 20,000) spectroscopic survey of Galactic stars, and is one of the four experiments in the SDSS-III suite. APOGEE will provide, by orders of magnitude, the largest uniform database of chemical abundances, spectroscopic parallaxes and kinematics for Galactic stars across the bulge, disk, and halo. The survey will be conducted with a dedicated, 300-fiber, cryogenic, spectrograph operating in the H-band, to be built at the University of Virginia. APOGEE will use approximately half of the time on 150 bright nights each year during a three-year period to observe, at high S/N, of order 100,000 giant stars selected directly from 2MASS down to a flux limit of H 13.5. Many of the targets will be located in the inner Galaxy, towards the Galactic bulge/bar and disk, often in regions never accessed by optical observations. With its high resolution and S/N, APOGEE will determine, for a vast sample, accurate abundance patterns, spanning numerous chemical species, and precision radial velocities, with better than 0.5 km/s accuracy. Some of the scientific objectives of this survey are to (1) provide extensive chemodynamical data on the inner Galaxy (thin/thick disk, bar/bulge, low latitude halo substructure) sufficient to constrain formation/evolution models, (2) place constraints on the first stars from unbiased metallicity distribution functions of these stellar populations, (3) constrain and understand physical processes of star formation, feedback, mixing in the formation of the Galaxy, (4) survey the dynamics of the bulge and disk, and place constraints on the nature and influence of the Galactic bar and spiral arms, (5) attempt to isolate what portion of the disk and bulge come from accretion versus formation in situ. Title: The Fifth Data Release of the Sloan Digital Sky Survey Authors: Adelman-McCarthy, Jennifer K.; Agüeros, Marcel A.; Allam, Sahar S.; Anderson, Kurt S. J.; Anderson, Scott F.; Annis, James; Bahcall, Neta A.; Bailer-Jones, Coryn A. L.; Baldry, Ivan K.; Barentine, J. C.; Beers, Timothy C.; Belokurov, V.; Berlind, Andreas; Bernardi, Mariangela; Blanton, Michael R.; Bochanski, John J.; Boroski, William N.; Bramich, D. M.; Brewington, Howard J.; Brinchmann, Jarle; Brinkmann, J.; Brunner, Robert J.; Budavári, Tamás; Carey, Larry N.; Carliles, Samuel; Carr, Michael A.; Castander, Francisco J.; Connolly, A. J.; Cool, R. J.; Cunha, Carlos E.; Csabai, István; Dalcanton, Julianne J.; Doi, Mamoru; Eisenstein, Daniel J.; Evans, Michael L.; Evans, N. W.; Fan, Xiaohui; Finkbeiner, Douglas P.; Friedman, Scott D.; Frieman, Joshua A.; Fukugita, Masataka; Gillespie, Bruce; Gilmore, G.; Glazebrook, Karl; Gray, Jim; Grebel, Eva K.; Gunn, James E.; de Haas, Ernst; Hall, Patrick B.; Harvanek, Michael; Hawley, Suzanne L.; Hayes, Jeffrey; Heckman, Timothy M.; Hendry, John S.; Hennessy, Gregory S.; Hindsley, Robert B.; Hirata, Christopher M.; Hogan, Craig J.; Hogg, David W.; Holtzman, Jon A.; Ichikawa, Shin-ichi; Ichikawa, Takashi; Ivezić, Željko; Jester, Sebastian; Johnston, David E.; Jorgensen, Anders M.; Jurić, Mario; Kauffmann, Guinevere; Kent, Stephen M.; Kleinman, S. J.; Knapp, G. R.; Kniazev, Alexei Yu.; Kron, Richard G.; Krzesinski, Jurek; Kuropatkin, Nikolay; Lamb, Donald Q.; Lampeitl, Hubert; Lee, Brian C.; Leger, R. French; Lima, Marcos; Lin, Huan; Long, Daniel C.; Loveday, Jon; Lupton, Robert H.; Mandelbaum, Rachel; Margon, Bruce; Martínez-Delgado, David; Matsubara, Takahiko; McGehee, Peregrine M.; McKay, Timothy A.; Meiksin, Avery; Munn, Jeffrey A.; Nakajima, Reiko; Nash, Thomas; Neilsen, Eric H., Jr.; Newberg, Heidi Jo; Nichol, Robert C.; Nieto-Santisteban, Maria; Nitta, Atsuko; Oyaizu, Hiroaki; Okamura, Sadanori; Ostriker, Jeremiah P.; Padmanabhan, Nikhil; Park, Changbom; Peoples, John, Jr.; Pier, Jeffrey R.; Pope, Adrian C.; Pourbaix, Dimitri; Quinn, Thomas R.; Raddick, M. Jordan; Re Fiorentin, Paola; Richards, Gordon T.; Richmond, Michael W.; Rix, Hans-Walter; Rockosi, Constance M.; Schlegel, David J.; Schneider, Donald P.; Scranton, Ryan; Seljak, Uroš; Sheldon, Erin; Shimasaku, Kazu; Silvestri, Nicole M.; Smith, J. Allyn; Smolčić, Vernesa; Snedden, Stephanie A.; Stebbins, Albert; Stoughton, Chris; Strauss, Michael A.; SubbaRao, Mark; Suto, Yasushi; Szalay, Alexander S.; Szapudi, István; Szkody, Paula; Tegmark, Max; Thakar, Aniruddha R.; Tremonti, Christy A.; Tucker, Douglas L.; Uomoto, Alan; Vanden Berk, Daniel E.; Vandenberg, Jan; Vidrih, S.; Vogeley, Michael S.; Voges, Wolfgang; Vogt, Nicole P.; Weinberg, David H.; West, Andrew A.; White, Simon D. M.; Wilhite, Brian; Yanny, Brian; Yocum, D. R.; York, Donald G.; Zehavi, Idit; Zibetti, Stefano; Zucker, Daniel B. Bibcode: 2007ApJS..172..634A Altcode: 2007arXiv0707.3380A This paper describes the Fifth Data Release (DR5) of the Sloan Digital Sky Survey (SDSS). DR5 includes all survey quality data taken through 2005 June and represents the completion of the SDSS-I project (whose successor, SDSS-II, will continue through mid-2008). It includes five-band photometric data for 217 million objects selected over 8000 deg2 and 1,048,960 spectra of galaxies, quasars, and stars selected from 5713 deg2 of that imaging data. These numbers represent a roughly 20% increment over those of the Fourth Data Release; all the data from previous data releases are included in the present release. In addition to ``standard'' SDSS observations, DR5 includes repeat scans of the southern equatorial stripe, imaging scans across M31 and the core of the Perseus Cluster of galaxies, and the first spectroscopic data from SEGUE, a survey to explore the kinematics and chemical evolution of the Galaxy. The catalog database incorporates several new features, including photometric redshifts of galaxies, tables of matched objects in overlap regions of the imaging survey, and tools that allow precise computations of survey geometry for statistical investigations. Title: New Close Binary Systems from the SDSS-I (Data Release Five) and the Search for Magnetic White Dwarfs in Cataclysmic Variable Progenitor Systems Authors: Silvestri, Nicole M.; Lemagie, Mara P.; Hawley, Suzanne L.; West, Andrew A.; Schmidt, Gary D.; Liebert, James; Szkody, Paula; Mannikko, Lee; Wolfe, Michael A.; Barentine, J. C.; Brewington, Howard J.; Harvanek, Michael; Krzesinski, Jurik; Long, Dan; Schneider, Donald P.; Snedden, Stephanie A. Bibcode: 2007AJ....134..741S Altcode: 2007arXiv0704.0789S We present the latest catalog of more than 1200 spectroscopically selected close binary systems observed with the Sloan Digital Sky Survey through Data Release Five. We use the catalog to search for magnetic white dwarfs in cataclysmic variable progenitor systems. Given that approximately 25% of cataclysmic variables contain a magnetic white dwarf, and that our large sample of close binary systems should contain many progenitors of cataclysmic variables, it is quite surprising that we find only two potential magnetic white dwarfs in this sample. The candidate magnetic white dwarfs, if confirmed, would possess relatively low magnetic field strengths (BWD<10 MG) that are similar to those of intermediate Polars but are much less than the average field strength of the current Polar population. Additional observations of these systems are required to definitively cast the white dwarfs as magnetic. Even if these two systems prove to be the first evidence of detached magnetic white dwarf + M dwarf binaries, there is still a large disparity between the properties of the presently known cataclysmic variable population and the presumed close binary progenitors. Title: VizieR Online Data Catalog: Luminosity function of M7-L8 ultracool dwarfs (Cruz+, 2007) Authors: Cruz, K. L.; Reid, I. N.; Kirkpatrick, J. D.; Burgasser, A. J.; Liebert, J.; Solomon, A. R.; Schmidt, S. J.; Allen, P. R.; Hawley, S. L.; Covey, K. R. Bibcode: 2007yCat..51330439C Altcode: We present a 20pc, volume-limited sample of M7-L8 dwarfs created through spectroscopic follow-up of sources selected from the Two Micron All Sky Survey Second Incremental Release Point Source Catalog. In this paper we present optical spectroscopy of 198 candidate nearby ultracool dwarfs, including 12 late-M and L dwarfs likely to be within 20pc of the Sun and 94 more distant late-type dwarfs. We have also identified five ultracool dwarfs with spectral signatures of low gravity. Combining these data with previous results, we define a sample of 99 ultracool dwarfs in 91 systems within 20pc. These are used to estimate the J- and K-band luminosity functions for dwarfs with optical spectral types between M7 and L8 (10.5<MJ<15, 9.5<MKs<13). We find a space density of 4.9x10-3/pc3 for late-M dwarfs (M7-M9.5) and a lower limit of 3.8x10-3/pc3 for L dwarfs.

(8 data files). Title: Characterizing The Near-UV Environment Of M Dwarfs Authors: Walkowicz, Lucianne M.; Johns-Krull, C. M.; Hawley, S. L. Bibcode: 2007AAS...210.1705W Altcode: 2007BAAS...39Q.118W We report the results of our HST snapshot survey with the ACS HRC PR200L prism, designed to measure the near-UV emission in a sample of nearby M dwarfs. 33 stars were observed, spanning the mass range from 0.1 - 0.6 solar masses (T 2200K - 4000K) where the UV energy distributions vary widely between active and inactive stars. The strength and distribution of this UV emission can have critical consequences for the atmospheres of attendant planets. These observations provide much-needed constraints on models of the habitability zone and the atmospheres of possible terrestrial planets orbiting M dwarf hosts, and will be used to refine the target selection for future space missions such as TPF. These NUV data will also be used in conjunction with existing optical, FUV and X-ray data to constrain a new generation of M dwarf atmospheric models, and to explore unanswered questions regarding the dynamo generation and magnetic heating in these low-mass stars. Title: Meeting the Cool Neighbors. IX. The Luminosity Function of M7-L8 Ultracool Dwarfs in the Field Authors: Cruz, Kelle L.; Reid, I. Neill; Kirkpatrick, J. Davy; Burgasser, Adam J.; Liebert, James; Solomon, Adam R.; Schmidt, Sarah J.; Allen, Peter R.; Hawley, Suzanne L.; Covey, Kevin R. Bibcode: 2007AJ....133..439C Altcode: 2006astro.ph..9648C We present a 20 pc, volume-limited sample of M7-L8 dwarfs created through spectroscopic follow-up of sources selected from the Two Micron All Sky Survey Second Incremental Release Point Source Catalog. In this paper we present optical spectroscopy of 198 candidate nearby ultracool dwarfs, including 12 late-M and L dwarfs likely to be within 20 pc of the Sun and 94 more distant late-type dwarfs. We have also identified five ultracool dwarfs with spectral signatures of low gravity. Combining these data with previous results, we define a sample of 99 ultracool dwarfs in 91 systems within 20 pc. These are used to estimate the J- and K-band luminosity functions for dwarfs with optical spectral types between M7 and L8 (10.5<MJ<15, 9.5<MKS<13). We find a space density of 4.9×10-3 pc-3 for late-M dwarfs (M7-M9.5) and a lower limit of 3.8×10-3 pc-3 for L dwarfs. Title: Low-Mass Dwarf Template Spectra from the Sloan Digital Sky Survey Authors: Bochanski, John J.; West, Andrew A.; Hawley, Suzanne L.; Covey, Kevin R. Bibcode: 2007AJ....133..531B Altcode: 2006astro.ph.10639B We present template spectra of low-mass (M0-L0) dwarfs derived from over 4000 Sloan Digital Sky Survey spectra. These composite spectra are suitable for use as medium-resolution (R~1800) radial velocity standards. We report mean spectral properties (molecular band-head strengths, equivalent widths) and use the templates to investigate the effects of magnetic activity and metallicity on the spectroscopic and photometric properties of low-mass stars. Title: Near-Ultraviolet Spectra of Flares on YZ CMi Authors: Hawley, Suzanne L.; Walkowicz, Lucianne M.; Allred, Joel C.; Valenti, Jeff A. Bibcode: 2007PASP..119...67H Altcode: 2006astro.ph.11074H Near-ultraviolet spectroscopic data obtained with the Hubble Space Telescope STIS (Space Telescope Imaging Spectrograph) instrument on the dMe flare star YZ Canis Minoris (YZ CMi) were analyzed. Flare and quiet intervals were identified from the broadband near-UV light curve, and the spectrum of each flare was separately extracted. Mg II and Fe II line profiles show similar behavior during the flares. Two large flares allowed time-resolved spectra to be analyzed, revealing a very broad component to the Mg II k line profile in at least one flare spectrum (F9b). If interpreted as a velocity, this component requires chromospheric material to be moving with FWHM ~ 250 km s-1, implying kinetic energy far in excess of the radiative energy. The Mg II k flare line profiles were compared to recent radiative hydrodynamic models of flare atmospheres undergoing electron beam heating. The models successfully predict red enhancements in the line profile, with a typical velocity of a few km s-1, but do not reproduce the flares showing blue enhancements, or the strongly broadened line observed in flare F9b. A more complete calculation of redistribution into the line wings, including the effect of collisions with the electron beam, may resolve the origin of the excess line broadening. Title: Measuring the Luminosity Function of Low-Mass Stars with Matched Survey Datasets Authors: Covey, Kevin R.; Bochanski, J. J.; Hawley, S. L.; Davenport, J.; Reid, I.; Golimowski, D. Bibcode: 2006AAS...209.2708C Altcode: 2006BAAS...38S.940C We present an initial measurement of the luminosity and mass functions of low mass stars as constructed from a catalog of matched Sloan Digital Sky Survey (SDSS) and 2 Micron All Sky Survey (2MASS) point sources. We have assembled a photometric catalog of 25,000+ matched SDSS and 2MASS point sources, spanning over 30 square degrees on the sky. We have also obtained follow-up spectroscopy, complete to J=16, of 500+ low mass dwarf candidates within a 1 square degree sub-sample, and thousands of additional dwarf candidates in the remaining 29 square degrees. This spectroscopic sample verifies that less than 1% of the photometric catalog is affected by incompleteness, contamination, or bias. Using this sample, we derive the luminosity and mass functions of low-mass stars over nearly a decade in mass ( 0.7 Msolar < M* < 0.1 Msolar), and compare our findings to previous results. Having validated this method to generate a low mass luminosity function from matched SDSS/2MASS datasets, future studies will enable extending this technique to the entirety of the SDSS/2MASS overlap. Title: Exploring the Local Milky Way: M Dwarfs as Tracers of Galactic Populations Authors: Bochanski, John J.; Hawley, S. L.; Munn, J. A.; Covey, K. R.; West, A. A.; Walkowicz, L. M. Bibcode: 2006AAS...20917214B Altcode: 2006BAAS...38.1149B We utilize Sloan Digital Sky Survey observations of over 8,000 low-mass dwarfs to examine Galactic structure and kinematics in the Southern (b -60 deg) Milky Way. Combining medium-resolution (R 1,800) spectroscopy, five band (ugriz) photometry and proper motion measurements, this dataset represents a powerful tool for examining the local structure and kinematics of the thin and thick disks. For each star, we have measured the activity (using the H-alpha luminosity) and UVW velocities. These measurements, as functions of distance from the Galactic Plane, offer a glimpse into the mean structural and kinematic properties of the thin and thick disk populations.

The authors gratefully acknowledge the support of NSF grants AST02-05875 and AST06-07644 and NASA ADP grant NAG5-13111 Title: New Close Binary Systems from the SDSS-I (Data Release Five) and the Orbital Periods for a Subset of Close White Dwarf + M Dwarf Systems Authors: Silvestri, Nicole M.; Hawley, S. L.; Dang, L. C.; Krogsrud, D. A.; Smoke, K.; Wolfe, M. A.; Mannikko, L. Bibcode: 2006AAS...20916218S Altcode: 2006BAAS...38Q1128S We present the latest catalog of more than 1200 spectroscopically selected close binary systems observed with the Sloan Digital Sky Survey (SDSS) through the now public Data Release Five. We use the systems from this catalog to study the influence of the binary environment on the evolution of the low-mass (typically an M dwarf) secondary star. We investigate how the properties of the M dwarf are impacted by the presence of the white dwarf primary using a variety of methods. Candidate systems with very active secondaries and/or low-mass primaries are observed using time-series spectroscopy on the ARC 3.5m to find their orbital periods. Preliminary orbital periods from repeat observations from the SDSS are also presented. In addition to the orbital period study, candidates are observed using photometric time-series on the MDM 2.4m to search for variability (eclipses, rotational modulation) and infrared photometry on the ARC 3.5m to search for faint, low-mass companions. We have now compiled a sample of systems with a wide range of spectral types, orbital periods and ages, and will discuss our results on the properties of these systems. Title: Using the Galactic Dynamics of M7 Dwarfs to Infer the Evolution of Their Magnetic Activity Authors: West, Andrew A.; Bochanski, John J.; Hawley, Suzanne L.; Cruz, Kelle L.; Covey, Kevin R.; Silvestri, Nicole M.; Reid, I. Neill; Liebert, James Bibcode: 2006AJ....132.2507W Altcode: 2006astro.ph..9001W We present a spectroscopic study and dynamical analysis of ~2600 M7 dwarfs. We confirm our previous finding that the fraction of magnetically active stars decreases with vertical distance from the Galactic plane. We also show that the mean luminosity of the Hα emission has a small but statistically significant decrease with distance. Using space motions for ~1300 stars and a simple one-dimensional dynamical simulation, we demonstrate that the drop in the activity fraction of M7 dwarfs can be explained by thin disk dynamical heating and a rapid decrease of magnetic activity at a mean stellar age of ~6-7 Gyr. Title: Time Variation in the Magnetic Activity of Cool Stars Authors: West, Andrew A.; Wright, J. T.; Marcy, G. W.; Agueros, M.; Walkowicz, L. M.; Hilton, E. J.; Hawley, S. L.; Bochanski, J. J.; Covey, K. R. Bibcode: 2006AAS...209.8904W Altcode: 2006BAAS...38.1024W We present results from the analysis of multi-epoch, spectral observations of magnetically active M-dwarfs. Using data from the California and Carnegie Planet Search Program, the Sloan Digital Sky Survey, and follow-up observations at Apache Point Observatory, we examine the time variation of chromospheric magnetic activity (as traced by the H-alpha, H-beta and Calcium K emission lines). We investigate the amplitude of activity variation in individual stars and compare this to the spread in activity seen in large SDSS samples of M-dwarfs. The data suggest that the activity variation of individual stars cannot explain the range of activity seen in the SDSS sample, indicating there is an intrinsic spread of activity strength in the M-dwarf population. In addition, we examine differences in the observed activity variation between the measured emission lines. Our analysis puts important constraints on the range of chromospheric temperatures predicted from models of M-dwarf dynamos. Title: Tracers of Chromospheric Structure: Observations of CaII K and Hα in M Dwarfs Authors: Walkowicz, Lucianne M.; Hawley, S. L. Bibcode: 2006AAS...209.1403W Altcode: 2006BAAS...38R.915W We report on our observing program to capture simultaneous high resolution spectra of Ca II and Balmer lines in a sample of nearby M3 dwarfs. Our goal is to investigate the chromospheric heating required to produce both of these lines at the observed levels. We present the results of our observing program so far, and discuss the application of these results as empirical constraints on models of quiescent M dwarf atmospheres. We also present initial model calculations and place them in the context of the data. Title: Flare Rate Analysis of M-Dwarf Lightcurves Authors: Kowalski, Adam F.; Hilton, E. J.; Becker, A. C.; Hawley, S. L. Bibcode: 2006AAS...209.8907K Altcode: 2006BAAS...38.1025K We present a preliminary variability index analysis of lightcurves of several thousand M-dwarfs extracted from the Sloan Digital Sky Survey Equatorial Stripe. These objects have been subclassed by magnetic activity and spectral type. This analysis will provide the rates of flaring activity as a function of the above parameters as well as characterizing the colors of these stars while active. M-dwarf flare rates will be applicable to next-generation time domain surveys such as the Large Synoptic Survey Telescope by predicting the fraction of observed variable objects that are flaring M-dwarfs and not other cosmological transients. Title: Improvement in the SDSS Photometric Calibration for Red Stars Authors: Davenport, James R.; Bochanski, J.; Covey, K.; Hawley, S. Bibcode: 2006AAS...209.9712D Altcode: 2006BAAS...38.1037D The SDSS has been an extremely fruitful survey for the study of late-type stars and other inherently red objects. Because of the breadth of the survey, it is important that all of the photometric data be calibrated on the standard SDSS 2.5m ugriz system. However, for stars redder than r-i > 0.6, the stellar locus measured with the SDSS 2.5m telescope begins to diverge from the SDSS photometric telescope calibration measurements using the presently derived color transformations. We use photometry of hundreds of late type stars that have been measured with both the SDSS 2.5m and the SDSS photometric telescope to obtain improved color transformations between the two telescopes for stars with red colors. These data will be particularly useful for calibrating an improved photometric parallax relation for low mass stars. Title: The Age-Activity Relation for M dwarfs Using 25,000 SDSS Spectra Authors: Hawley, Suzanne L.; West, A. A.; Bochanski, J. J.; Covey, K. R. Bibcode: 2006AAS...209.8906H Altcode: 2006BAAS...38.1025H The age at which strong surface magnetic activity ceases in M dwarfs has been inferred to have a strong dependence on mass (spectral type, surface temperature) to explain previous results showing a large increase in the fraction of active stars at later spectral types. Using spectral observations of 25,000 M dwarfs in the SDSS, we show that the fraction of active stars decreases as a function of vertical distance from the Galactic plane, and that the magnitude of this decrease changes significantly for different M spectral types. Adopting a simple dynamical model for thin disk vertical heating, we assign an age for the activity decline at each spectral type, and thus determine an activity-age relation for M dwarfs. These results provide constraints for dynamo models that seek to describe the production of surface magnetic fields in low mass stars. Title: From Radio to X-Ray: The Quiescent Atmosphere of the dMe Flare Star EV Lacertae Authors: Osten, Rachel A.; Hawley, Suzanne L.; Allred, Joel; Johns-Krull, Christopher M.; Brown, Alexander; Harper, Graham M. Bibcode: 2006ApJ...647.1349O Altcode: 2006astro.ph..4255O We report on multiwavelength observations spanning radio to X-ray wavelengths of the M dwarf flare star EV Lacertae and probing the characteristics of the outer atmospheric plasma from the upper chromosphere to the corona. We detect the star at a wavelength of 2 cm (15 GHz) for the first time. UV and FUV line profiles show evidence of nonthermal broadening, and the velocity width appears to peak at lower temperatures than in the Sun; this trend is confirmed in another active M dwarf flare star. Electron density measurements indicate nearly constant electron pressures between logT=5.2 and 6.4. At higher coronal temperatures, there is a sharp increase of 2 orders of magnitude in density (ne~1013 cm-3 at logT=6.9). X-ray, EUV, FUV, and NUV spectra constrain the differential emission measure (DEM) from the upper chromosphere through the corona. The coronal pressures are inconsistent with the assumption of hydrostatic equilibrium, either through emission measure (EM) modeling or application of scaling laws, and imply large conductive loss rates and a large energy input at the highest temperatures. The timescales for radiative and conductive losses in EV Lac's upper atmosphere imply that significant continued heating must occur for the corona to maintain its quiescent properties. The high-frequency radio detection requires the high-temperature X-ray-emitting coronal plasma to be spatially distinct from the radio emission source. Length scales in the low-temperature corona are markedly larger than those in the high-temperature corona, further suggestions of an inhomogeneous mixture of thermal and nonthermal coronal plasma. Title: Radiative Hydrodynamic Models of Optical and Ultraviolet Emission from M Dwarf Flares Authors: Allred, Joel C.; Hawley, Suzanne L.; Abbett, William P.; Carlsson, Mats Bibcode: 2006ApJ...644..484A Altcode: 2006astro.ph..3195A We report on radiative hydrodynamic simulations of M dwarf stellar flares and compare the model predictions to observations of several flares. The flares were simulated by calculating the hydrodynamic response of a model M dwarf atmosphere to a beam of nonthermal electrons. Radiative back-warming through numerous soft X-ray, extreme-ultraviolet, and ultraviolet transitions are also included. The equations of radiative transfer and statistical equilibrium are treated in non-LTE for many transitions of hydrogen, helium, and the Ca II ion, allowing the calculation of detailed line profiles and continuum radiation. Two simulations were carried out, with electron beam fluxes corresponding to moderate and strong beam heating. In both cases we find that the dynamics can be naturally divided into two phases: an initial gentle phase in which hydrogen and helium radiate away much of the beam energy and an explosive phase characterized by large hydrodynamic waves. During the initial phase, lower chromospheric material is evaporated into higher regions of the atmosphere, causing many lines and continua to brighten dramatically. The He II 304 line is especially enhanced, becoming the brightest line in the flaring spectrum. The hydrogen Balmer lines also become much brighter and show very broad line widths, in agreement with observations. We compare our predicted Balmer decrements to decrements calculated for several flare observations and find the predictions to be in general agreement with the observations. During the explosive phase both condensation and evaporation waves are produced. The moderate flare simulation predicts a peak evaporation wave of ~130 km s-1 and a condensation wave of ~30 km s-1. The velocity of the condensation wave matches velocities observed in several transition region lines. The optical continuum also greatly intensifies, reaching a peak increase of 130% (at 6000 Å) for the strong flare, but does not match observed white-light spectra. Title: Erratum: ``Spectroscopic Survey of M Dwarfs within 100 Parsecs of the Sun'' (AJ, 130, 1871 [2005]) Authors: Bochanski, John J.; Hawley, Suzanne L.; Reid, I. Neill; Covey, Kevin R.; West, Andrew A.; Tinney, C. G.; Gizis, John E. Bibcode: 2006AJ....131.3136B Altcode: In Table 2 of the recent paper titled ``Spectroscopic Survey of M Dwarfs within 100 Parsecs of the Sun'' by Bochanski et al., the authors presented UVW space velocities, proper motions, radial velocities, and distances to the 574 M dwarfs within their sample. The UVW motions were then examined as a function of vertical distance from the Galactic plane, with a discussion on the significance of the results and their application to dynamic heating models.

The authors have discovered an error in the calculation of the UVW motions. During the preparation of the manuscript, the computed space motions were not accurately recorded for a given star, resulting in sporadic errors throughout Table 2 and the subsequent analysis. In addition, the authors want to explicitly state that the UVW motions, corrected to the local standard of rest, are in a right-handed system, with a positive U-velocity in the direction of the Galactic center.

The new space velocities for the M dwarfs within this sample affect Tables 2 and 4-6 and Figures 8 and 9. The new values are included below, but the authors stress that the original conclusions presented in § 6 of the original paper remain valid. In the new version of Figure 9, the general decrease in velocity dispersion of the broad component (circles) with distance from the plane is preserved, along with the mostly constant dispersion of the narrow velocity dispersion component (squares). For completeness, a new illustrative demonstration of our kinematic analysis is shown, along with updated versions of Tables 4-6, which present the details of the kinematic analysis for UVW.

The authors sincerely regret any confusion introduced by this error and wish to thank Francesca Figueras for helpful discussion. Title: A Radiative Hydrodynamic Simulation of the 23 July 2002 Solar Flare Authors: Allred, J. C.; Hawley, S. L. Bibcode: 2006AGUSMSH52A..01A Altcode: We report on a simulation of the 23 July 2002 X-class solar flare. The flare was simulated by modeling the radiative hydrodynamic response of the solar atmosphere to a beam of non-thermal electrons. The electron beam spectrum was inferred from X-ray spectra obtained by RHESSI during the 23 July flare. The total beam flux and energy distribution vary as a function of time allowing us to investigate temporal correlations of the electron beam with the observed spectral response. In particular, we investigate the correlation of the beam heating rate with the white light increase. Our flare simulations include detailed non-LTE, optically thick radiative transfer which is crucial for understanding how energy is transported from the chromosphere deep into the photosphere where the white light is produced. During the course of the flare simulation we find the level of increase in white light matches well with observations of similarly sized white light flares. Title: A Catalog of Spectroscopically Selected Close Binary Systems from the Sloan Digital Sky Survey Data Release Four Authors: Silvestri, Nicole M.; Hawley, Suzanne L.; West, Andrew A.; Szkody, Paula; Bochanski, John J.; Eisenstein, Daniel J.; McGehee, Peregrine; Schmidt, Gary D.; Smith, J. Allyn; Wolfe, Michael A.; Harris, Hugh C.; Kleinman, Scot J.; Liebert, James; Nitta, Atsuko; Barentine, J. C.; Brewington, Howard J.; Brinkmann, John; Harvanek, Michael; Krzesiński, Jurek; Long, Dan; Neilsen, Eric H., Jr.; Schneider, Donald P.; Snedden, Stephanie A. Bibcode: 2006AJ....131.1674S Altcode: We present a spectroscopic sample of 747 detached close binary systems from the Sloan Digital Sky Survey (SDSS) Fourth Data Release. The majority of these binaries consist of a white dwarf primary and a low-mass secondary (typically M dwarf) companion. We have determined the temperature and gravity for 496 of the white dwarf primaries and the spectral type and magnetic activity properties for 661 of the low-mass secondaries. We have estimated the distances for each of the white dwarf-main-sequence star binaries and use white dwarf evolutionary grids to establish the age of each binary system from the white dwarf cooling times. With respect to a spectroscopically identified sample of ~8000 isolated M dwarf stars in the SDSS, the M dwarf secondaries show enhanced activity with a higher active fraction at a given spectral type. The white dwarf temperatures and gravities are similar to the distribution of ~1900 DA white dwarfs from the SDSS. The ages of the binaries in this study range from ~0.5 Myr to nearly 3 Gyr (average age ~0.20 Gyr). Title: Optical Spectroscopy of a Flare on Barnard's Star Authors: Paulson, Diane B.; Allred, Joel C.; Anderson, Ryan B.; Hawley, Suzanne L.; Cochran, William D.; Yelda, Sylvana Bibcode: 2006PASP..118..227P Altcode: 2005astro.ph.11281P We present optical spectra of a flare on Barnard's star. Several photospheric and chromospheric species were enhanced by the flare heating. An analysis of the Balmer lines shows that their shapes are best explained by Stark broadening rather than chromospheric mass motions. We estimate the temperature of the flaring region in the lower atmosphere to be >=8000 K and the electron density to be ~1014 cm-3, similar to values observed in other dM flares. Because Barnard's star is considered to be one of our oldest neighbors, a flare of this magnitude is probably quite rare. Title: The Fourth Data Release of the Sloan Digital Sky Survey Authors: Adelman-McCarthy, Jennifer K.; Agüeros, Marcel A.; Allam, Sahar S.; Anderson, Kurt S. J.; Anderson, Scott F.; Annis, James; Bahcall, Neta A.; Baldry, Ivan K.; Barentine, J. C.; Berlind, Andreas; Bernardi, Mariangela; Blanton, Michael R.; Boroski, William N.; Brewington, Howard J.; Brinchmann, Jarle; Brinkmann, J.; Brunner, Robert J.; Budavári, Tamás; Carey, Larry N.; Carr, Michael A.; Castander, Francisco J.; Connolly, A. J.; Csabai, István; Czarapata, Paul C.; Dalcanton, Julianne J.; Doi, Mamoru; Dong, Feng; Eisenstein, Daniel J.; Evans, Michael L.; Fan, Xiaohui; Finkbeiner, Douglas P.; Friedman, Scott D.; Frieman, Joshua A.; Fukugita, Masataka; Gillespie, Bruce; Glazebrook, Karl; Gray, Jim; Grebel, Eva K.; Gunn, James E.; Gurbani, Vijay K.; de Haas, Ernst; Hall, Patrick B.; Harris, Frederick H.; Harvanek, Michael; Hawley, Suzanne L.; Hayes, Jeffrey; Hendry, John S.; Hennessy, Gregory S.; Hindsley, Robert B.; Hirata, Christopher M.; Hogan, Craig J.; Hogg, David W.; Holmgren, Donald J.; Holtzman, Jon A.; Ichikawa, Shin-ichi; Ivezić, Željko; Jester, Sebastian; Johnston, David E.; Jorgensen, Anders M.; Jurić, Mario; Kent, Stephen M.; Kleinman, S. J.; Knapp, G. R.; Kniazev, Alexei Yu.; Kron, Richard G.; Krzesinski, Jurek; Kuropatkin, Nikolay; Lamb, Donald Q.; Lampeitl, Hubert; Lee, Brian C.; Leger, R. French; Lin, Huan; Long, Daniel C.; Loveday, Jon; Lupton, Robert H.; Margon, Bruce; Martínez-Delgado, David; Mandelbaum, Rachel; Matsubara, Takahiko; McGehee, Peregrine M.; McKay, Timothy A.; Meiksin, Avery; Munn, Jeffrey A.; Nakajima, Reiko; Nash, Thomas; Neilsen, Eric H., Jr.; Newberg, Heidi Jo; Newman, Peter R.; Nichol, Robert C.; Nicinski, Tom; Nieto-Santisteban, Maria; Nitta, Atsuko; O'Mullane, William; Okamura, Sadanori; Owen, Russell; Padmanabhan, Nikhil; Pauls, George; Peoples, John, Jr.; Pier, Jeffrey R.; Pope, Adrian C.; Pourbaix, Dimitri; Quinn, Thomas R.; Richards, Gordon T.; Richmond, Michael W.; Rockosi, Constance M.; Schlegel, David J.; Schneider, Donald P.; Schroeder, Joshua; Scranton, Ryan; Seljak, Uroš; Sheldon, Erin; Shimasaku, Kazu; Smith, J. Allyn; Smolčić, Vernesa; Snedden, Stephanie A.; Stoughton, Chris; Strauss, Michael A.; SubbaRao, Mark; Szalay, Alexander S.; Szapudi, István; Szkody, Paula; Tegmark, Max; Thakar, Aniruddha R.; Tucker, Douglas L.; Uomoto, Alan; Vanden Berk, Daniel E.; Vandenberg, Jan; Vogeley, Michael S.; Voges, Wolfgang; Vogt, Nicole P.; Walkowicz, Lucianne M.; Weinberg, David H.; West, Andrew A.; White, Simon D. M.; Xu, Yongzhong; Yanny, Brian; Yocum, D. R.; York, Donald G.; Zehavi, Idit; Zibetti, Stefano; Zucker, Daniel B. Bibcode: 2006ApJS..162...38A Altcode: 2005astro.ph..7711A This paper describes the Fourth Data Release of the Sloan Digital Sky Survey (SDSS), including all survey-quality data taken through 2004 June. The data release includes five-band photometric data for 180 million objects selected over 6670 deg2 and 673,280 spectra of galaxies, quasars, and stars selected from 4783 deg2 of those imaging data using the standard SDSS target selection algorithms. These numbers represent a roughly 27% increment over those of the Third Data Release; all the data from previous data releases are included in the present release. The Fourth Data Release also includes an additional 131,840 spectra of objects selected using a variety of alternative algorithms, to address scientific issues ranging from the kinematics of stars in the Milky Way thick disk to populations of faint galaxies and quasars. Title: Investigating the late stages of stellar evolution with long period variables from MACHO and 2MASS Authors: Fraser, Oliver J.; Hawley, Suzanne L.; Cook, Kem H. Bibcode: 2006MmSAI..77..519F Altcode: 2005astro.ph..9569F We are re-analyzing the MACHO variable star database to explore the relationships between pulsation, evolution, and mass loss in evolved stars. We will analyze the multi-periodic properties of long period variable (LPV) stars, 50% of which could not be assigned any period in the original analysis. Recent results show that the missing stars may be an important element in understanding the origin of the period-luminosity sequences observed in the LMC. Our goal is to characterize the morphology and periodic properties of these stars, and then use the stars' 2MASS colors along with theoretical isochrones to understand their mass loss and evolution. We will develop a luminosity-independent criteria to classify the LMC LPVs, which can then be applied to Galactic LPVs. This will enable a synthesis of knowledge between LPVs in the LMC and the well-studied Galactic examples. Title: The Radio Spectrum of TVLM 513-46546: Constraints on the Coronal Properties of a Late M Dwarf Authors: Osten, Rachel A.; Hawley, Suzanne L.; Bastian, Timothy S.; Reid, I. Neill Bibcode: 2006ApJ...637..518O Altcode: 2005astro.ph..9762O We explore the radio emission from the M9 dwarf TVLM 513-46546 at multiple radio frequencies, determining the flux spectrum of persistent radio emission, as well as constraining the levels of circular polarization. Detections at both 3.6 and 6 cm provide a spectral index measurement α (where Sν~να) of -0.4+/-0.1. A detection at 20 cm suggests that the spectral peak is between 1.4 and 5 GHz. The most stringent upper limits on circular polarization are at 3.6 and 6 cm, with V/I<15%. These characteristics agree well with those of typical parameters for early- to mid-type M dwarfs, confirming that magnetic activity is present at levels comparable with those extrapolated from earlier M dwarfs. We apply analytic models to investigate the coronal properties under simple assumptions of dipole magnetic field geometry and radially varying nonthermal electron density distributions. Requiring the spectrum to be optically thin at frequencies higher than 5 GHz and reproducing the observed 3.6 cm fluxes constrains the magnetic field at the base to be less than about 500 G. There is no statistically significant periodicity in the 3.6 cm light curve, but it is consistent with low-level variability. Title: SDSS spectroscopic survey of stars. Authors: Ivezić, Ž.; Schlegel, D.; Uomoto, A.; Bond, N.; Beers, T.; Allende Prieto, C.; Wilhelm, R.; Lee, Y. Sun; Sivarani, T.; Jurić, M.; Lupton, R.; Rockosi, C.; Knapp, G.; Gunn, J.; Yanny, B.; Jester, S.; Kent, S.; Pier, J.; Munn, J.; Richards, G.; Newberg, H.; Blanton, M.; Eisenstein, D.; Hawley, S.; Anderson, S.; Harris, H.; Kiuchi, F.; Chen, A.; Bushong, J.; Sohi, H.; Haggard, D.; Kimball, A.; Barentine, J.; Brewington, H.; Harvanek, M.; Kleinman, S.; Krzesinski, J.; Long, D.; Nitta, A.; Snedden, S.; SDSS Collaboration Bibcode: 2006MmSAI..77.1057I Altcode: 2007astro.ph..1509I In addition to optical photometry of unprecedented quality, the Sloan Digital Sky Survey (SDSS) is also producing a massive spectroscopic database. We discuss determination of stellar parameters, such as effective temperature, gravity and metallicity from SDSS spectra, describe correlations between kinematics and metallicity, and study their variation as a function of the position in the Galaxy. We show that stellar parameter estimates by Beers et al. show a good correlation with the position of a star in the g-r vs. u-g color-color diagram, thereby demonstrating their robustness as well as a potential for photometric parameter estimation methods. Using Beers et al. parameters, we find that the metallicity distribution of the Milky Way stars at a few kpc from the galactic plane is bimodal with a local minimum at [Z/Z_⊙] ∼ -1.3. The median metallicity for the low-metallicity [Z/Z_⊙]< -1.3 subsample is nearly independent of Galactic cylindrical coordinates R and z, while it decreases with z for the high-metallicity [Z/Z_⊙]> -1.3 sample. We also find that the low-metallicity sample has ∼2.5 times larger velocity dispersion and that it does not rotate (at the ∼10 km/s level), while the rotational velocity of the high-metallicity sample decreases smoothly with the height above the galactic plane. Title: Low Mass Template Spectra from SDSS Authors: Bochanski, J. J.; West, A. A.; Hawley, S. L.; Covey, K. R. Bibcode: 2005AAS...20713107B Altcode: 2005BAAS...37.1378B We present mean template spectra of low mass dwarfs as observed by the Sloan Digital Sky Survey (SDSS). These extremely high signal-to-noise templates result from co-adding observations of stars with similar spectral types. We make use of ∼ 12,000 unique low mass stellar spectra to construct a set of templates spanning the spectral types, M0-L2. We measure the spectral and photometric properties of these mean templates, and report on H-alpha emission (due to chromospheric activity) and molecular band strengths. These pristine spectra are suitable for use as radial velocity cross-correlation templates as well as illuminating many of the mean properties of low mass stars.

We gratefully acknowledge the support of NSF grant AST02-05875 and NASA ADP grant NAG5-13111. Title: Testing LMC Microlensing Scenarios: The Discrimination Power of the SuperMACHO Microlensing Survey Authors: Rest, A.; Stubbs, C.; Becker, A. C.; Miknaitis, G. A.; Miceli, A.; Covarrubias, R.; Hawley, S. L.; Smith, R. C.; Suntzeff, N. B.; Olsen, K.; Prieto, J. L.; Hiriart, R.; Welch, D. L.; Cook, K. H.; Nikolaev, S.; Huber, M.; Prochtor, G.; Clocchiatti, A.; Minniti, D.; Garg, A.; Challis, P.; Keller, S. C.; Schmidt, B. P. Bibcode: 2005ApJ...634.1103R Altcode: 2005astro.ph..9240R Characterizing the nature and spatial distribution of the lensing objects that produce the previously measured microlensing optical depth toward the Large Magellanic Cloud (LMC) remains an open problem. We present an appraisal of the ability of the SuperMACHO Project, a next-generation microlensing survey directed toward the LMC, to discriminate between various proposed lensing populations. We consider two scenarios: lensing by a uniform foreground screen of objects and self-lensing by LMC stars. The optical depth for ``screen lensing'' is essentially constant across the face of the LMC, whereas the optical depth for self-lensing shows a strong spatial dependence. We have carried out extensive simulations, based on data obtained during the first year of the project, to assess the SuperMACHO survey's ability to discriminate between these two scenarios. In our simulations we predict the expected number of observed microlensing events for various LMC models for each of our fields by adding artificial stars to the images and estimating the spatial and temporal efficiency of detecting microlensing events using Monte Carlo methods. We find that the event rate itself shows significant sensitivity to the choice of the LMC luminosity function, limiting the conclusions that can be drawn from the absolute rate. If instead we determine the differential event rate across the LMC, we will decrease the impact of these systematic biases and render our conclusions more robust. With this approach the SuperMACHO Project should be able to distinguish between the two categories of lens populations. This will provide important constraints on the nature of the lensing objects and their contributions to the Galactic dark matter halo. Title: Seven Days in the Life of AR Lac Authors: Ayres, T. R.; Brown, A.; Harper, G. M.; Korhonen, H.; Redfield, S.; Hawley, S. L.; Optical Support Team Bibcode: 2005AAS...20717505A Altcode: 2005BAAS...37.1445A A week-long pointing on the short-period eclipsing RS CVn binary AR Lac (K0IV+G4IV; P=2d) by the Far-Ultraviolet Spectroscopic Explorer was coordinated with groundbased optical Doppler mapping, to provide an unprecedented view of structure, energetics, and dynamics of subcoronal activity, through time-resolved measurements of FUV diagnostics like C III λ 977, O VI λ 1031, and (coronal forbidden line) Fe XVIII λ 974. The observation was carried out over the period 29 November to 7 December 2004, with a total exposure of 225 ks, covering four revolutions of the binary. Three large flares were captured during this period, and numerous smaller ones, mainly on the K subgiant primary. We discuss the appearance of the FUV activity on the surfaces of the two hyperactive companions, with special emphasis on the eclipse intervals.

This work was supported by a FUSE Guest Investigator grant. Title: The SDSS/2MASS Low Mass Stellar Luminosity Function: The Calibration Region Authors: Covey, K. R.; Hawley, S. L.; Bochanski, J. J.; SDSS Collaboration Bibcode: 2005AAS...207.4204C Altcode: 2005BAAS...37.1227C We present an initial measurement of the luminosity and mass functions of low mass stars as constructed from a catalog of matched Sloan Digital Sky Survey (SDSS) and 2 Micron All Sky Survey (2MASS) point sources. We have assembled a photometric catalog of 25,000+ matched SDSS and 2MASS point sources, spanning over 30 square degrees on the sky. We have also obtained follow-up spectroscopy, complete to J=16, of 500+ low mass dwarf candidates within a 1 square degree sub-sample, and thousands of additional dwarf candidates in the remaining 29 square degrees. We have used this spectroscopic sample to assess the impact of, and correct for, photometric biases and contamination by distinct classes of astronomical objects found in nearby regions of color space (e.g. hi-z QSOs). Having validated this method to generate a low mass luminosity function from matched SDSS/2MASS datasets, future studies will enable extending this technique to the entirety of the SDSS/2MASS overlap.

The authors gratefully acknowledge the NASA ADP and GSRP programs for funding which enabled this work. Title: Spectroscopic Survey of M Dwarfs within 100 Parsecs of the Sun Authors: Bochanski, John J.; Hawley, Suzanne L.; Reid, I. Neill; Covey, Kevin R.; West, Andrew A.; Tinney, C. G.; Gizis, John E. Bibcode: 2005AJ....130.1871B Altcode: We have constructed a sample of M dwarfs out to a distance of ~100 pc. This sample of 605 stars (574 M dwarfs and 31 K dwarfs) have been spectroscopically observed, yielding spectral types, radial velocities, Hα equivalent widths, and molecular band indices. Photometric observations have been compiled, with photographic plates providing RI magnitudes and JHKs magnitudes from Two Micron All Sky Survey observations. Proper motions were determined by a match to USNO-B, and distances were computed employing a spectroscopic parallax, allowing the computation of UVW space motions. These data were used to investigate the distribution of magnetically active stars within the solar neighborhood. We find that there is no statistically significant variation in activity for equidistant locations above and below the Galactic plane. We also confirm prior kinematic analysis of large samples of M dwarfs, finding that active stars form a dynamically colder population. Title: VizieR Online Data Catalog: A preliminary 20pc census from the NLTT catalogue (Reid+, 2004) Authors: Reid, I. N.; Cruz, K. L.; Allen, P.; Mungall, F.; Kilkenny, D.; Liebert, J.; Hawley, S. L.; Fraser, O. J.; Covey, K. R.; Lowrance, P.; Kirkpatrick, J. D.; Burgasser, A. J. Bibcode: 2005yCat..51280463R Altcode: Continuing our census of late-type dwarfs in the solar neighborhood, we present BVRI photometry and optical spectroscopy of 800 mid-type M dwarfs drawn from the NLTT proper-motion catalog. The targets are taken both from our own cross-referencing of the NLTT Catalogue and the 2MASS Second Incremental Data Release, and from the revised NLTT compiled recently by Salim & Gould (Cat. <J/ApJ/582/1011>). All are identified as nearby-star candidates based on their location in the (mr, mr-Ks) diagram. Three hundred stars discussed here have previous astrometric, photometric, or spectroscopic observations. We present new BVRI photometry for 101 stars, together with low-resolution spectroscopy of a further 400 dwarfs.

(10 data files). Title: Status of Abundance Determinations for Low Mass Dwarfs and Subdwarfs Authors: Hawley, S. L. Bibcode: 2005ASPC..336...69H Altcode: In this talk, I will review the status of abundance determinations for M dwarfs and M subdwarfs. Most results come from photometric data (position of the star in a calibrated color magnitude diagram) and/or low resolution studies of molecular band-strengths. These methods give only rough estimates of the metallicity. A few high resolution studies have been attempted, and more are in progress. The calibration of low resolution abundance indicators using these high resolution studies offers the best hope for obtaining metallicities of large samples of stars in the future. Title: Radiative Hydrodynamic Models of the Optical and Ultraviolet Emission from Solar Flares Authors: Allred, Joel C.; Hawley, Suzanne L.; Abbett, William P.; Carlsson, Mats Bibcode: 2005ApJ...630..573A Altcode: 2005astro.ph..7335A We report on radiative hydrodynamic simulations of moderate and strong solar flares. The flares were simulated by calculating the atmospheric response to a beam of nonthermal electrons injected at the apex of a one-dimensional closed coronal loop and include heating from thermal soft X-ray, extreme ultraviolet, and ultraviolet (XEUV) emission. The equations of radiative transfer and statistical equilibrium were treated in non-LTE and solved for numerous transitions of hydrogen, helium, and Ca II, allowing the calculation of detailed line profiles and continuum emission. This work improves on previous simulations by incorporating more realistic nonthermal electron beam models and includes a more rigorous model of thermal XEUV heating. We find that XEUV back-warming contributes less than 10% of the heating, even in strong flares. The simulations show elevated coronal and transition region densities resulting in dramatic increases in line and continuum emission in both the UV and optical regions. The optical continuum reaches a peak increase of several percent, which is consistent with enhancements observed in solar white-light flares. For a moderate flare (~M class), the dynamics are characterized by a long gentle phase of near balance between flare heating and radiative cooling, followed by an explosive phase with beam heating dominating over cooling and characterized by strong hydrodynamic waves. For a strong flare (~X class), the gentle phase is much shorter, and we speculate that for even stronger flares the gentle phase may be essentially nonexistent. During the explosive phase, synthetic profiles for lines formed in the upper chromosphere and transition region show blueshifts corresponding to a plasma velocity of ~120 km s-1, and lines formed in the lower chromosphere show redshifts of ~40 km s-1. Title: Updated Colors for Cool Stars in the Sloan Digital Sky Survey Authors: West, Andrew A.; Walkowicz, Lucianne M.; Hawley, Suzanne L. Bibcode: 2005PASP..117..706W Altcode: We present updated colors for M and L dwarfs based on photometry from the third data release of the Sloan Digital Sky Survey (SDSS). These data are improved in quality and number from earlier results. We also provide updated equations for determining photometric parallaxes from SDSS colors of late-type stars. Walkowicz et al. have recently presented new techniques for studying the magnetic activity of low-mass stars, and their method relies on an accurate determination of SDSS color. We derive new relationships between SDSS colors and other common passbands and present updated formulas from Walkowicz et al. for determining the level of magnetic activity in M and L dwarfs. Title: The Magnetic Properties of an L Dwarf Derived from Simultaneous Radio, X-Ray, and Hα Observations Authors: Berger, E.; Rutledge, R. E.; Reid, I. N.; Bildsten, L.; Gizis, J. E.; Liebert, J.; Martín, E.; Basri, G.; Jayawardhana, R.; Brandeker, A.; Fleming, T. A.; Johns-Krull, C. M.; Giampapa, M. S.; Hawley, S. L.; Schmitt, J. H. M. M. Bibcode: 2005ApJ...627..960B Altcode: 2005astro.ph..2384B We present the first simultaneous, multiwavelength observations of an L dwarf, the L3.5 candidate brown dwarf 2MASS J00361617+1821104, conducted with the Very Large Array, the Chandra X-Ray Observatory, and the Kitt Peak 4 m telescope. We detect strongly variable and periodic radio emission (P=3 hr) with a fraction of about 60% circular polarization. No X-ray emission is detected to a limit of LX/Lbol<~2×10-5, several hundred times below the saturation level observed in early M dwarfs. Similarly, we do not detect Hα emission to a limit of LHα/Lbol<~2×10-7, the deepest for any L dwarf observed to date. The ratio of radio to X-ray luminosity is at least 4 orders of magnitude in excess of that observed in a wide range of active stars (including M dwarfs), providing the first direct confirmation that late-M and L dwarfs violate the radio/X-ray correlation. The radio emission is due to gyrosynchrotron radiation in a large-scale magnetic field of about 175 G, which is maintained on timescales longer than 3 yr. The detected 3 hr period may be due to (1) the orbital motion of a companion at a separation of about 5 stellar radii, similar to the configuration of RS CVn systems, (2) an equatorial rotation velocity of about 37 km s-1 and an anchored, long-lived magnetic field, or (3) periodic release of magnetic stresses in the form of weak flares. In the case of orbital motion, the magnetic activity may be induced by the companion, possibly explaining the unusual pattern of activity and the long-lived signal. We conclude that fully convective stars can maintain a large-scale and stable magnetic field, but the lack of X-ray and Hα emission indicates that the atmospheric conditions are markedly different than in early-type stars and even M dwarfs. Similar observations are therefore invaluable for probing both the internal and external structure of low-mass stars and substellar objects, and for providing constraints on dynamo models. Title: Characterizing the Near-UV Environment of M Dwarfs: Implications for Extrasolar Planetary Searches and Astrobiology Authors: Hawley, Suzanne Bibcode: 2005hst..prop10525H Altcode: We propose SNAP observations with the ACS HRC PR200L prism, designed to measure the near ultraviolet emission in a sample of 107 nearby M dwarfs. The sample spans the mass range from 0.1 - 0.6 solar masses {temperature range 2200K - 4000K} where the UV energy distributions vary widely between active and inactive stars. The strength and distribution of this UV emission can have critical consequences for the atmospheres of attendant planets. Our proposed observations will provide desperately needed constraints on models of the habitability zone and the atmospheres of possible terrestrial planets orbiting M dwarf hosts, and will be used to sharpen TPF target selection. In addition, the NUV data will be used in conjunction with existing optical, FUV and X-ray data to constrain a new generation of M dwarf atmospheric models, and to explore unanswered questions regarding the dynamo generation and magnetic heating in these low-mass stars. Title: The SuperMACHO Microlensing Survey Authors: Becker, Andrew C.; Rest, A.; Stubbs, C.; Miknaitis, G. A.; Miceli, A.; Covarrubias, R.; Hawley, S. L.; Aguilera, C.; Smith, R. C.; Suntzeff, N. B.; Olsen, K.; Prieto, J. L.; Hiriart, R.; Garg, A.; Welch, D. L.; Cook, K. H.; Nikolaev, S.; Clocchiatti, A.; Minniti, D.; Keller, S. C.; Schmidt, B. P. Bibcode: 2005IAUS..225..357B Altcode: 2004astro.ph..9167B We present the first results from our next-generation microlensing survey, the SuperMACHO project. We are using the CTIO 4m Blanco telescope and the MOSAIC imager to carry out a search for microlensing toward the Large Magellanic Cloud (LMC). We plan to ascertain the nature of the population responsible for the excess microlensing rate seen by the MACHO project. Our observing strategy is optimized to measure the differential microlensing rate across the face of the LMC. We find this derivative to be relatively insensitive to the details of the LMC's internal structure but a strong discriminant between Galactic halo and LMC self lensing. In December 2003 we completed our third year of survey operations. 2003 also marked the first year of real-time microlensing alerts and photometric and spectroscopic followup. We have extracted several dozen microlensing candidates, and we present some preliminary light curves and related information. Similar to the MACHO project, we find SNe behind the LMC to be a significant contaminant - this background has not been completely removed from our current single-color candidate sample. Our follow-up strategy is optimized to discriminate between SNe and true microlensing. Title: Cool Stars: Red Dwarfs and Brown Dwarfs Authors: Hawley, S. L. Bibcode: 2005AAS...206.2201H Altcode: 2005BAAS...37Q.463H Low mass red dwarfs and brown dwarfs are the coolest stars in the sky. I will review our current knowledge of these objects and discuss some interesting problems in their formation and evolution. Title: The Chromospheric Activity and Ages of M Dwarf Stars in Wide Binary Systems Authors: Silvestri, Nicole M.; Hawley, Suzanne L.; Oswalt, Terry D. Bibcode: 2005AJ....129.2428S Altcode: 2005astro.ph..2305S We investigate the relationship between age and chromospheric activity for 139 M dwarf stars in wide binary systems with white dwarf companions. The age of each system is determined from the cooling age of its white dwarf component. The current limit for activity-age relations found for M dwarfs in open clusters is 4 Gyr. Our unique approach to finding ages for M stars allows for the exploration of this relationship at ages older than 4 Gyr. The general trend of stars remaining active for a longer time at a later spectral type is confirmed. However, our larger sample and greater age range reveal additional complexity in assigning age based on activity alone. We find that M dwarfs in wide binaries older than 4 Gyr depart from the loglinear relation for clusters and are found to have activity at magnitudes, colors, and masses that are brighter, bluer, and more massive than predicted by the cluster relation. In addition to our activity-age results, we present the measured radial velocities and complete space motions for 161 white dwarf stars in wide binaries.

Based on observations obtained with the Apache Point Observatory 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium; the Cerro Tololo Inter-American Observatory 4.0 m telescope, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under a cooperative agreement with the National Science Foundation (NSF) as part of the National Optical Astronomy Observatory (NOAO), which also operates Kitt Peak National Observatory in Tucson, Arizona; and the SARA Observatory 0.9 m telescope at Kitt Peak, which is owned and operated by the Southeastern Association for Research in Astronomy (http://www.saraobservatory.org). Title: Where Are the Magnetic White Dwarfs with Detached, Nondegenerate Companions? Authors: Liebert, James; Wickramasinghe, Dayal T.; Schmidt, Gary D.; Silvestri, Nicole M.; Hawley, Suzanne L.; Szkody, Paula; Ferrario, Lilia; Webbink, Ronald F.; Oswalt, Terry D.; Smith, J. Allyn; Lemagie, Mara P. Bibcode: 2005AJ....129.2376L Altcode: The Sloan Digital Sky Survey has already more than doubled the sample of white dwarfs with spectral classifications, the subset with detached M dwarf companions, and the subset of magnetic white dwarfs. In the course of assessing these new discoveries, we have noticed a curious, unexpected property of the total lists of magnetic white dwarfs and of white dwarf plus main-sequence binaries: there appears to be virtually zero overlap between the two samples! No confirmed magnetic white dwarf has yet been found in such a pairing with a main-sequence star. The same statement can be made for the samples of white dwarf-M dwarf pairs in wide, common proper motion systems. This contrasts with the situation for interacting binaries, in which an estimated 25% of the accreting systems have a magnetic white dwarf primary. Alternative explanations are discussed for the observed absence of magnetic white dwarf-main-sequence pairs, but the recent discoveries of very low accretion rate magnetic binaries pose difficulties for each. A plausible explanation may be that the presence of the companion and the likely large mass and small radius of the magnetic white dwarf (relative to nonmagnetic degenerate dwarfs) may provide a selection effect against the discovery of the latter in such binary systems. More careful analysis of the existing samples may yet uncover members of this class of binary, and the sample sizes will continue to grow. The question of whether the mass and field distributions of the magnetic primaries in interacting binaries are similar to those of the isolated magnetic white dwarfs (including those in wider binaries) must also be answered. Title: Status Report on the SDSS-II Supernova Survey Authors: Kessler, R.; Adelman-McCarthy, J.; Barentine, J.; Becker, A.; Boroski, W.; Brewington, H.; Connolly, A.; DeJongh, F.; Dembicky, J.; Dilday, B.; Doi, M.; Frieman, J.; Gunn, J.; Harvanek, M.; Hawley, S.; Hendry, J.; Hoeflich, P.; Hogan, C.; Holtzman, J.; Inkmann, J.; Johnston, D.; Kaplan, J.; Ketzeback, B.; Kilper, G.; Kleinman, A.; Kleinman, S.; Kron, R. G.; Krughoff, S.; Krzesinski, J.; Lamenti, D.; Lampeitl, H.; Long, D.; Marriner, J.; McMillan, R.; Miknaitis, G.; Newman, P. R.; Nichol, R.; Riess, A. G.; Romani, R.; Sako, M.; Scranton, R.; Snedden, S.; Stoughton, C.; Subbarao, M.; Tucker, D.; Wang, L.; Yasuda, N.; Yocum, D.; York, D. Bibcode: 2005AAS...206.1507K Altcode: 2005BAAS...37..457K The SDSS-II Supernova Survey is a proposed optical survey to discover supernovae in the redshift range 0.05 < z < 0.35, and to measure their lightcurves for use as a probe of dark energy. The poster will present preliminary results of a test campaign in the Fall of 2004, as well as a proposal for a three-year run in 2005-2007.

A feasibility study in September-November of 2004 used the 2.5 m SDSS telescope at APO to repeat-scan 140 sq. degrees every other night. These scans were used to discover SN and to measure their lightcurves. A reduction pipeline running at APO was used to find SN candidates (g and r bands only) within 2 days; spectra for these candidates were taken by the ARC 3.5 m and HET telescopes. This test run resulted in 16 spectroscopically confirmed SN Ia, 5 type II and one type Ic.

The SDSS-II proposal is a three-year program to measure 200 SN Ia lightcurves in the five SDSS bands (ugriz). Compared to the 2004 test run, we anticipate lightcurve yield improvements as follows: > 2 from longer campaigns, x2 from increased sky coverage (along with scanning every night instead of every other night), and better detection efficiency from improved software. In addition to using the ARC 3.5 and HET telescopes for spectroscopy, proposals are pending to use the Subaru 8m, WHT 4.2m, NTT 3.5m, VLT 10m, and the Calar Alto 3.5m.

Funding for the Sloan Digital Sky Survey (SDSS) has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Aeronautics and Space Administration, the National Science Foundation, the U.S. Department of Energy, the Japanese Monbukagakusho, and the Max Planck Society. Title: Updated Colors for Cool Stars in the SDSS Authors: West, Andrew A.; Walkowicz, Lucianne M.; Hawley, Suzanne L. Bibcode: 2005astro.ph..4673W Altcode: We present updated colors for M and L dwarfs based on photometry from the third data release of the Sloan Digital Sky Survey (SDSS). These data are improved in quality and number from earlier results. We also provide updated equations for determining photometric parallaxes from SDSS colors of late-type stars. Walkowicz, Hawley & West (2004) have recently presented new techniques for studying the magnetic activity of low-mass stars and their method relies on an accurate determination of SDSS color. We derive new relationships between SDSS colors and other common passbands and present updated formulas from Walkowicz et al. (2004) for determining the level of magnetic activity in M and L dwarfs. Title: The Third Data Release of the Sloan Digital Sky Survey Authors: Abazajian, Kevork; Adelman-McCarthy, Jennifer K.; Agüeros, Marcel A.; Allam, Sahar S.; Anderson, Kurt S. J.; Anderson, Scott F.; Annis, James; Bahcall, Neta A.; Baldry, Ivan K.; Bastian, Steven; Berlind, Andreas; Bernardi, Mariangela; Blanton, Michael R.; Bochanski, John J., Jr.; Boroski, William N.; Brewington, Howard J.; Briggs, John W.; Brinkmann, J.; Brunner, Robert J.; Budavári, Tamás; Carey, Larry N.; Castander, Francisco J.; Connolly, A. J.; Covey, Kevin R.; Csabai, István; Dalcanton, Julianne J.; Doi, Mamoru; Dong, Feng; Eisenstein, Daniel J.; Evans, Michael L.; Fan, Xiaohui; Finkbeiner, Douglas P.; Friedman, Scott D.; Frieman, Joshua A.; Fukugita, Masataka; Gillespie, Bruce; Glazebrook, Karl; Gray, Jim; Grebel, Eva K.; Gunn, James E.; Gurbani, Vijay K.; Hall, Patrick B.; Hamabe, Masaru; Harbeck, Daniel; Harris, Frederick H.; Harris, Hugh C.; Harvanek, Michael; Hawley, Suzanne L.; Hayes, Jeffrey; Heckman, Timothy M.; Hendry, John S.; Hennessy, Gregory S.; Hindsley, Robert B.; Hogan, Craig J.; Hogg, David W.; Holmgren, Donald J.; Holtzman, Jon A.; Ichikawa, Shin-ichi; Ichikawa, Takashi; Ivezić, Željko; Jester, Sebastian; Johnston, David E.; Jorgensen, Anders M.; Jurić, Mario; Kent, Stephen M.; Kleinman, S. J.; Knapp, G. R.; Kniazev, Alexei Yu.; Kron, Richard G.; Krzesinski, Jurek; Lamb, Donald Q.; Lampeitl, Hubert; Lee, Brian C.; Lin, Huan; Long, Daniel C.; Loveday, Jon; Lupton, Robert H.; Mannery, Ed; Margon, Bruce; Martínez-Delgado, David; Matsubara, Takahiko; McGehee, Peregrine M.; McKay, Timothy A.; Meiksin, Avery; Ménard, Brice; Munn, Jeffrey A.; Nash, Thomas; Neilsen, Eric H., Jr.; Newberg, Heidi Jo; Newman, Peter R.; Nichol, Robert C.; Nicinski, Tom; Nieto-Santisteban, Maria; Nitta, Atsuko; Okamura, Sadanori; O'Mullane, William; Owen, Russell; Padmanabhan, Nikhil; Pauls, George; Peoples, John; Pier, Jeffrey R.; Pope, Adrian C.; Pourbaix, Dimitri; Quinn, Thomas R.; Raddick, M. Jordan; Richards, Gordon T.; Richmond, Michael W.; Rix, Hans-Walter; Rockosi, Constance M.; Schlegel, David J.; Schneider, Donald P.; Schroeder, Joshua; Scranton, Ryan; Sekiguchi, Maki; Sheldon, Erin; Shimasaku, Kazu; Silvestri, Nicole M.; Smith, J. Allyn; Smolčić, Vernesa; Snedden, Stephanie A.; Stebbins, Albert; Stoughton, Chris; Strauss, Michael A.; SubbaRao, Mark; Szalay, Alexander S.; Szapudi, István; Szkody, Paula; Szokoly, Gyula P.; Tegmark, Max; Teodoro, Luis; Thakar, Aniruddha R.; Tremonti, Christy; Tucker, Douglas L.; Uomoto, Alan; Vanden Berk, Daniel E.; Vandenberg, Jan; Vogeley, Michael S.; Voges, Wolfgang; Vogt, Nicole P.; Walkowicz, Lucianne M.; Wang, Shu-i.; Weinberg, David H.; West, Andrew A.; White, Simon D. M.; Wilhite, Brian C.; Xu, Yongzhong; Yanny, Brian; Yasuda, Naoki; Yip, Ching-Wa; Yocum, D. R.; York, Donald G.; Zehavi, Idit; Zibetti, Stefano; Zucker, Daniel B. Bibcode: 2005AJ....129.1755A Altcode: 2004astro.ph.10239A This paper describes the Third Data Release of the Sloan Digital Sky Survey (SDSS). This release, containing data taken up through 2003 June, includes imaging data in five bands over 5282 deg2, photometric and astrometric catalogs of the 141 million objects detected in these imaging data, and spectra of 528,640 objects selected over 4188 deg2. The pipelines analyzing both images and spectroscopy are unchanged from those used in our Second Data Release. Title: From Radio to X-Ray: Flares on the dMe Flare Star EV Lacertae Authors: Osten, Rachel A.; Hawley, Suzanne L.; Allred, Joel C.; Johns-Krull, Christopher M.; Roark, Christine Bibcode: 2005ApJ...621..398O Altcode: 2004astro.ph.11236O We present the results of a campaign to observe flares on the M dwarf flare star EV Lacertae over the course of two days in 2001 September, utilizing a combination of radio continuum, optical photometric and spectroscopic, ultraviolet spectroscopic, and X-ray spectroscopic observations to characterize the multiwavelength nature of flares from this active, single, late-type star. We find flares in every wavelength region in which we observed. A large radio flare from the star was observed at both 3.6 and 6 cm and is the most luminous example of a gyrosynchrotron flare yet observed on a dMe flare star. The radio flare can be explained as encompassing a large magnetic volume, comparable to the stellar disk, and involving trapped electrons that decay over timescales of hours. Flux enhancements at 6 cm accompanied by highly negatively circularly polarized emission (πc-->-100%) imply that a coherent emission mechanism is operating in the corona of EV Lac. There are numerous optical white-light flares, and yet no signature of emission-line response from the chromosphere appears. Two small ultraviolet enhancements differ in the amount of nonthermal broadening present. There are numerous X-ray flares occurring throughout the observation, and an analysis of undispersed photons and grating events reveals no evidence for abundance variations. Higher temperatures are present during some flares; however, the maximum temperature achieved varies from flare to flare. There is no evidence for density variations during any flare intervals. In the multiwavelength context, the start of the intense radio flare is coincident with an impulsive optical U-band flare, to within 1 minute, and yet there is no signature of an X-ray response. There are other intervals of time when optical flaring and UV flaring is occurring, but these cannot be related to the contemporaneous X-ray flaring: the time-integrated luminosities do not match the instantaneous X-ray flare luminosity, as one would expect for the Neupert effect. We investigate the probability of chance occurrences of flares from disparate wavelength regions producing temporal coincidences but find that not all the flare associations can be explained by a superposition of flares due to a high flaring rate. We caution against making causal associations of multiwavelength flares based solely on temporal correlations for high flaring rate stars such as EV Lac. Title: Radio observations of brown dwarfs Authors: Osten, R. A.; Hawley, S. L.; Bastian, T. S.; Reid, I. N. Bibcode: 2005ESASP.560..857O Altcode: 2005csss...13..857O No abstract at ADS Title: Long-Period Variables in the Large Magellanic Cloud: Results from MACHO and 2MASS Authors: Fraser, Oliver J.; Hawley, Suzanne L.; Cook, Kem H.; Keller, Stefan C. Bibcode: 2005AJ....129..768F Altcode: 2004astro.ph.10398F We use the 8 year light-curve database from the MAssive Compact Halo Objects project together with infrared colors and magnitudes from the Two Micron All Sky Survey to identify a sample of 22,000 long-period variables in the Large Magellanic Cloud (referred to hereafter as LMC LPVs). A period-luminosity diagram of these stars reveals six well-defined sequences, in substantial agreement with previous analyses of samples from the Optical Gravitational Lensing Experiment. In our analysis we identify analogues to Galactic LPVs in the LMC LPV sample. We find that carbon-dominated asymptotic giant branch (AGB) stars populate only two of the sequences, one of which includes the Mira variables. The high-luminosity end of the same two sequences are also the location of the only stars with J-Ks>2, indicating that they are enshrouded in dust. The unknown mechanism that drives the variability of stars in the longest period produces different morphology in the period-luminosity diagram as compared with the shortest period sequences, which are thought to be caused by pulsation. In particular, the longest period sequence extends to lower luminosity red giant branch stars, and the luminosity function does not peak among the AGB stars. We point out several features that will constrain new models of the period-luminosity sequences. Title: The Fall 2004 SDSS Supernova Survey Authors: Sako, Masao; Romani, Roger; Frieman, Josh; Adelman-McCarthy, Jen; Becker, Andrew; Dejongh, Fritz; Dilday, Ben; Estrada, Juan; Hendry, John; Holtzman, Jon; Kaplan, Jared; Kessler, Rick; Lampeitl, Hubert; Marriner, John; Miknaitis, Gajus; Riess, Adam; Tucker, Douglas; Barentine, John; Blandford, Roger; Brewington, Howard; Dembicky, Jack; Harvanek, Mike; Hawley, Suzanne; Hogan, Craig; Johnston, David; Kahn, Steve; Ketzeback, Bill; Kleinman, Scot; Krzesinski, Jerzy; Lamenti, Dennis; Long, Dan; McMillan, Russet; Newman, Peter; Nitta, Atsuko; Nichol, Robert; Scranton, Ryan; Sheldon, Erin; Snedden, Stephanie; Stoughton, Chris; York, Don; SDSS Collaboration Bibcode: 2005tsra.conf..415S Altcode: 2005astro.ph..4455S In preparation for the Supernova Survey of the Sloan Digital Sky Survey (SDSS) II, a proposed 3-year extension to the SDSS, we have conducted an early engineering and science run during the fall of 2004, which consisted of approximately 20 scheduled nights of repeated imaging of half of the southern equatorial stripe. Transient supernova-like events were detected in near real-time and photometric measurements were made in the five SDSS filter bandpasses with a cadence of ~ 2 days. Candidate type Ia supernovae (SNe) were pre-selected based on their colors, light curve shape, and the properties of the host galaxy. Follow-up spectroscopic observations were performed with the Astrophysical Research Consortium 3.5m telescope and the 9.2m Hobby-Eberly Telescope to confirm their types and measure the redshifts. The 2004 campaign resulted in 22 spectroscopically confirmed SNe, which includes 16 type Ia, 5 type II, and 1 type Ib/c. These SN Ia will help fill in the sparsely sampled redshift interval of z = 0.05-0.35, the so-called 'redshift desert', in the Hubble diagram. Detailed investigation of the spectral properties of these moderate-redshift SNe Ia will also provide a bridge between local SNe and high-redshift objects, and will help us understand the systematics for future cosmological applications that require high photometric precision. Finally, the large survey volume also provides the opportunity to select unusual supernovae for spectroscopic study that are poorly sampled in other surveys. We report on some of the early results from this program and discuss potential future applications. Title: New light on dark stars : red dwarfs, low-mass stars, brown dwarfs Authors: Reid, I. Neill; Hawley, Suzanne L. Bibcode: 2005nlds.book.....R Altcode: No abstract at ADS Title: The Search for Magnetic White Dwarfs in Pre-Cataclysmic Binaries from the SDSS Authors: Lemagie, M. P.; Silvestri, N. M.; Hawley, S. L.; Schmidt, G. D.; Liebert, J.; Wolfe, M. A. Bibcode: 2004AAS...20510305L Altcode: 2004BAAS...36Q1515L We present the results of our investigation of white dwarfs in several hundred close binary systems from the SDSS. The close binary systems in this study are believed to be the progenitors of cataclysmic variables. Since approximately 25% of the known cataclysmic variables have magnetic white dwarfs, many of the white dwarfs in our large sample of pre-cataclysmic binary systems should have a measurable magnetic field. A cursory inspection of the composite spectra of these systems however, reveals no obvious magnetic white dwarfs, possibly because of the low signal-to-noise of the spectrum and/or the contamination of the white dwarf spectrum by the low mass companion. To reduce the contamination, we first subtract the low mass companion from the composite SDSS spectrum. We then smooth and compare the Balmer absorption features of the remaining DA white dwarf spectrum to magnetic models at a variety of field strengths. Our search reveals only about 10 magnetic white dwarf stars in these systems. All of the candidate magnetic white dwarfs have relatively low magnetic field strengths (< 10 MG), as expected. Our techniques for finding magnetic white dwarfs in these systems, their physical properties, and the implications of our results are discussed.

This work was supported in part by NSF Grant AST02-05875. Title: First results from the SDSS Supernova Survey Authors: Lampeitl, H.; Adelman-McCarthy, J.; Barentine, J.; Becker, A.; Boroski, W.; Brewington, H.; Connolly, A.; DeJongh, F.; Dembicky, J.; Dilday, B.; Doi, M.; Frieman, J.; Gunn, J.; Harvanek, M.; Hawley, S.; Hendry, J.; Hoeflich, P.; Hogan, C.; Holtzman, J.; Inkmann, J.; Johnston, D.; Kaplan, J.; Kessler, R.; Ketzeback, B.; Kilper, G.; Kleinman, A.; Kleinman, S.; Kron, R. G.; Krughoff, S.; Krzesinski, J.; Lamenti, D.; Long, D.; Marriner, J.; McMillan, R.; Miknaitis, G.; Newman, P. R.; Nichol, R.; Riess, A.; Romani, R.; Sako, M.; Scranton, R.; Snedden, S.; Stoughton, C.; Subbarao, M.; Tucker, D.; Wang, L.; Yasuda, N.; Yocum, D. R.; York, D.; Sloan Digital Sky Survey Bibcode: 2004AAS...20511404L Altcode: 2005BAAS...37R.374L The SDSS Supernova Survey is a proposed optical survey to discover supernovae of type Ia (SN Ia) in the redshift range of z 0.1 to z<0.3. Data acquisition is intended to take place in the fall period of 2005, 2006 and 2007 and an additional feasibility study already carried out in 2004. The final survey will cover a region of approx. 200 sq. degrees along the celestial equator in imaging using the well calibrated and understood SDSS 2.5m telescope. Dedicated spectroscopic follow up observations will be carried out on the ARC 3.5m, the HET and various other telescopes to determine the type and the redshift of the supernovae. The complete survey is projected to discover approximately 200 SN Ia with well measured lightcurves.

The feasibility study carried out in October and November 2004 resulted in 11 useful nights of imaging data under various sky conditions and covered a field of view of approx 100 sq. degrees. The imaging data has been reduced and visually inspected usually within 48 hours to allow for fast spectroscopic follow up observations. So far more than 10 SN Ia have been identified spectroscopically by using the ARC 3.5m telescope and the HET. In addition several SN of various other types have been discovered. The poster will give an outline of the search strategy and will present preliminary lightcurves and spectra of the newly discovered supernova.

Funding for the Sloan Digital Sky Survey (SDSS) has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Aeronautics and Space Administration, the National Science Foundation, the U.S. Department of Energy, the Japanese Monbukagakusho, and the Max Planck Society. Title: Radio Observations of Brown Dwarfs Authors: Quick, L. C.; Osten, R.; Bastian, T.; Hawley, S. Bibcode: 2004AAS...205.1101Q Altcode: 2004BAAS...36.1351Q Radio emission commonly signifies the presence of magnetic activity in the coronae of late-type stars, while emission from the H-alpha transition is a sign of magnetic activity in their chromospheres. Surveys of H-alpha emission from ultracool dwarfs of spectral types late M, L, and T have not shown this indicator of magnetic activity. As a result, it was believed that all magnetic activity declined in these cool bodies. Although sparse, the most recent detections of radio emission contradict this behavior. As part of a large VLA survey of nearby ultracool dwarfs out to 13pc, the aim of my research was to determine how common radio emission is in these late-type stars. Data from 9 L and T dwarfs was reduced, and evidence for emission was detected from three of these objects. This research was conducted as a part of the NRAO Summer Student program, with partial funding from the National Science Foundation. Title: A Spectroscopic Survey of M Dwarfs within 100 Parsecs of the Sun Authors: Bochanski, J. J.; Hawley, S. L.; Reid, I. N.; Covey, K.; Munn, J. A.; Tinney, C. G. Bibcode: 2004AAS...205.5506B Altcode: 2004BAAS...36S1431B Low mass M dwarfs are the dominant stellar component in the Universe. Their ubiquity and longevity make them ideal tracers of galactic populations. Using 12 Schmidt plates from both northern and southern galactic hemispheres, we constructed a sample of M dwarfs to distances of about 100 pc, to investigate the dependence of magnetic activity on location in the Galaxy. We have also investigated the kinematics of active and non-active M dwarfs at various distances from the Galactic plane. We find that there is no statistically significant variation in activity for equidistant locations above and below the plane. We also confirm that active stars are a younger dynamical population.

We gratefully acknowledge the support of NSF grant AST02-05875 and NASA ADP grant NAG5-13111. Title: The Quiescent Atmosphere of the dMe Flare Star EV Lacertae Authors: Osten, R. A.; Hawley, S. L.; Johns-Krull, C. M.; Brown, A.; Allred, J. Bibcode: 2004AAS...205.5507O Altcode: 2004BAAS...36.1431O We report on multi-wavelength spectroscopic observations of the M dwarf flare star, EV Lacertae, during quiescent intervals. The study of extreme coronae, such as on M dwarf flare stars, allows an investigation into regimes of temperature, density, and activity not available from spatially detailed studies of our low-activity Sun. Our investigation makes use of simultaneous Chandra HETGS and HST/STIS high resolution spectra, along with non-contemporaneous FUSE and EUVE spectra, to probe the characteristics of the outer atmospheric plasma from the upper chromosphere to the corona. A detailed study of the coronal spectrum finds evidence of the inverse First Ionization Potential (FIP) effect, commonly seen in active stars. We examine the structures producing this emission through the shape of the emission measure distribution over a span of three decades in temperature, and the variation of electron density with electron temperature over a similar range. The correspondence of elements with ionic transitions in both X-ray and UV spectral ranges allows us to investigate the region in the atmosphere where the coronal abundance fractionation pattern begins.

RAO acknowledges funding through a Jansky fellowship from NRAO. RAO acknowledges funding through grants from SAO and STScI. Title: The Evolution of Low Mass Stars in Close Binary Systems Authors: Silvestri, N. M.; Hawley, S. L.; Szkody, P.; Bochanski, J. J.; West, A. A.; Fraser, O. J.; Covey, K. R.; Wolfe, M. A.; Vanlandingham, K. M.; Dang, L. C.; SDSS Collaboration Bibcode: 2004AAS...20512005S Altcode: 2004BAAS...36.1549S We report on our extensive investigation of the evolution of low mass stars in close binary systems with white dwarfs. Cataclysmic variables (CVs), which are the most numerous UV and X-ray sources in the Galaxy, and Type Ia supernovae, which are standard candles for cosmology, are believed to be the end products of these close binary systems, but little is known about their evolution before they reach the CV stage. In particular, we are studying the influence of the binary environment on the evolution of the low mass secondary star (typically an M dwarf), and investigating how the properties of the M dwarf are impacted by the presence of the white dwarf primary. Using our growing sample of over 700 M dwarf-white dwarf close binary systems identified spectroscopically in the Sloan Digital Sky Survey, we determine spectral types and magnetic activity properties of the M dwarfs, and effective temperatures and gravities of the white dwarfs, which allows us to determine their ages. Candidate systems with very active secondaries are then observed using time-series spectroscopy on the ARC 3.5m to find their orbital periods. Candidates are also observed using photometric time-series on the MDM 2.4m to search for variability (eclipses, rotational modulation). We have now compiled a sample of systems with a wide range of orbital period and age, and will discuss our results on the properties of the secondary stars, and compare them to recent field M dwarf studies (e.g. West et al. 2004).

This work was supported in part by NSF Grant AST02-05875. Title: The SDSS Supernova Survey Authors: Frieman, J.; Adelman-McCarthy, J.; Barentine, J.; Becker, A.; Boroski, W.; Brewington, H.; Connolly, A.; DeJongh, F.; Dembicky, J.; Dilday, B.; Doi, M.; Gunn, J.; Harvanek, M.; Hawley, S.; Hoeflich, P.; Hogan, C.; Holtzman, J.; Johnston, D.; Kaplan, J.; Kessler, R.; Ketzeback, B.; Kilper, G.; Kleinman, A.; Kleinman, S.; Kron, R. G.; Krughoff, S.; Krzesinski, J.; Lamenti, D.; Lampeitl, H.; Long, D.; Marriner, J.; McMillan, R.; Miknaitis, G.; Newman, P. R.; Nichol, R.; Riess, A.; Romani, R.; Sako, M.; Scranton, R.; Snedden, S.; Stoughton, C.; Subbarao, M.; Tucker, D.; Wang, L.; Yasuda, N.; York, D.; SDSS Affiliation Bibcode: 2004AAS...20512001F Altcode: 2004BAAS...36.1548F The proposed SDSS II includes a Supernova Survey that will encompass three 3-month seasons, Sept.-Nov. 2005-7, with the aim of obtaining well-sampled, well-calibrated, multi-band lightcurves for 200 Type Ia supernovae in the redshift `desert' z = 0.1-0.35. This sample, with photometric data over 250 square degrees imaged every other night from a single instrument with well-understood wavelength response, will yield improved constraints on the dark energy and enable detailed study of the systematics of the Ia population as they affect the use of these objects as standard candles for cosmology. The survey will include spectroscopic follow-up on other telescopes for SN identification and redshift determination, near-infrared imaging follow-up to constrain host galaxy extinction, and multi-epoch spectrophotometry for a subsample in order to obtain improved K corrections. In preparation for SDSS II, the collaboration is carrying out 20 nights of repeat imaging on the SDSS 2.5m telescope in Fall 2004, with follow-up planned on the ARC 3.5m, HET, and other telescopes. This talk will describe the goals, status, and early results from the SDSS Supernova Survey. It will also briefly describe the sample of nearby supernovae discovered in SDSS galaxy spectra.

Funding for the Sloan Digital Sky Survey (SDSS) has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Aeronautics and Space Administration, the National Science Foundation, the U.S. Department of Energy, the Japanese Monbukagakusho, and the Max Planck Society. Title: Thin Disk Dynamical Heating and the Activity of Low Mass Dwarfs Authors: Silvestri, N. M.; West, A. A.; Hawley, S. L.; Cruz, K.; Reid, I. N.; Liebert, J. W. Bibcode: 2004AAS...20511402S Altcode: 2004BAAS...36.1542S We present a continuing analysis of the magnetic activity of thousands of M-dwarfs from the Sloan Digital Sky Survey (SDSS) and 2MASS. We confirm the trend described by West et al. (2004) that the fraction of active stars decreases as a function of vertical distance from the galactic plane. This result suggests that the older stars, which have undergone more dynamical heating, are also less likely to remain active, a further confirmation of an age-activity relation. We also investigate a possible variation in the amount of activity (as measured by LH-alpha/Lbol) as a function of distance from the plane and find that there is no statistically significant trend. These data imply that older stars continue to have the same distribution of activity until they cease being active. Title: A Second Stellar Color Locus: a Bridge from White Dwarfs to M stars Authors: Smolcic, V.; Ivezic, Z.; Knapp, G. R.; Lupton, R. H.; Pavlovski, K.; Ilijic, S.; Schlegel, D.; Smith, J. A.; McGehee, P. M.; Silvestri, N. M.; Hawley, S. L.; Rockosi, C.; Gunn, J. E.; Strauss, M. A. Bibcode: 2004ASPC..318..396S Altcode: 2004ssrc.conf..396S We report the discovery of a locus of stars in the SDSS g-r vs. u-g color-color diagram that connects the colors of white dwarfs and M dwarfs. While its contrast with respect to the main stellar locus is only ∼1:2300, this previously unrecognized feature includes 863 stars from SDSS Data Release 1. The position and shape of the feature is in good agreement with predictions of a simple binary star model that consists of a white dwarf and an M dwarf, with the components' luminosity ratio controlling the position along this binary system locus. SDSS DR1 spectra for 47 of these objects strongly support this model. Title: A Second Stellar Color Locus: a Bridge from White Dwarfs to M stars Authors: Smolčić, Vernesa; Ivezić, Željko; Knapp, Gillian R.; Lupton, Robert H.; Pavlovski, Krešimir; Ilijić, Saša; Schlegel, David; Smith, J. Allyn; McGehee, Peregrine M.; Silvestri, Nicole M.; Hawley, Suzanne L.; Rockosi, Constance; Gunn, James E.; Strauss, Michael A.; Fan, Xiaohui; Eisenstein, Daniel; Harris, Hugh Bibcode: 2004ApJ...615L.141S Altcode: 2004astro.ph..3218S We report the discovery of a locus of binary stars in the Sloan Digital Sky Survey (SDSS) g-r versus u-g color-color diagram that connects the colors of white dwarfs and M dwarfs. While its contrast with respect to the main stellar locus is only ~1:2300, this previously unrecognized feature includes 863 stars from the SDSS Data Release 1 (DR1). The position and shape of the feature are in good agreement with predictions of a simple binary star model that consists of a white dwarf and an M dwarf, with the components' luminosity ratio controlling the position along this binary system locus. SDSS DR1 spectra for 47 of these objects strongly support this model. The absolute magnitude-color distribution inferred for the white dwarf component is in good agreement with the models of Bergeron et al. Title: The χ Factor: Determining the Strength of Activity in Low-Mass Dwarfs Authors: Walkowicz, Lucianne M.; Hawley, Suzanne L.; West, Andrew A. Bibcode: 2004PASP..116.1105W Altcode: 2004astro.ph.10422W We describe a new, distance-independent method for calculating the magnetic activity strength in low-mass dwarfs, LHα/Lbol. Using a well-observed sample of nearby stars and cool standards spanning spectral type M0.5 to L0, we compute χ, the ratio between the continuum flux near Hα and the bolometric flux, fλ6560/fbol. This ratio can be multiplied by the measured equivalent width of the Hα emission line to yield LHα/Lbol. We provide χ values for all objects in our sample, and also fits to χ as a function of color and average values by spectral type. This method was used by West et al. to examine trends in magnetic activity strength in low-mass stars. Title: Cataclysmic Variables from the Sloan Digital Sky Survey. III. The Third Year Authors: Szkody, Paula; Henden, Arne; Fraser, Oliver; Silvestri, Nicole; Bochanski, John; Wolfe, Michael A.; Agüeros, Marcel; Warner, Brian; Woudt, Patrick; Tramposch, Jonica; Homer, Lee; Schmidt, Gary; Knapp, Gillian R.; Anderson, Scott F.; Covey, Kevin; Harris, Hugh; Hawley, Suzanne; Schneider, Donald P.; Voges, Wolfgang; Brinkmann, J. Bibcode: 2004AJ....128.1882S Altcode: This paper continues the series that identifies new cataclysmic variables found in the Sloan Digital Sky Survey (SDSS). We present 36 cataclysmic variables and one possible symbiotic star from Sloan spectra obtained during 2002, of which 34 are new discoveries, two are known dwarf novae (BC UMa and KS UMa), and one is a known cataclysmic variable identified from the Two-Degree Field survey. The positions, colors, and spectra of all 37 systems are presented, along with follow-up spectroscopic/photometric observations of 10 systems. As in the past 2 yr of data, the new SDSS systems show a large variety of characteristics based on their inclination and magnetic fields, including three eclipsing systems, four with prominent He II emission, and 15 systems showing features of the underlying stars.

Based on observations obtained with the Sloan Digital Sky Survey and with the Apache Point Observatory (APO) 3.5 m telescope, which are owned and operated by the Astrophysical Research Consortium. Title: Chandra Observation of V426 Ophiuchi: Weighing the Evidence for a Magnetic White Dwarf Authors: Homer, Lee; Szkody, Paula; Raymond, John C.; Fried, Robert E.; Hoard, D. W.; Hawley, S. L.; Wolfe, M.; Tramposch, J. N.; Yirak, K. T. Bibcode: 2004ApJ...610..991H Altcode: 2004astro.ph..4289H We report the results of a 45 ks Chandra observation of the cataclysmic variable (CV) V426 Ophiuchus. The high-resolution spectrum from the high-energy transmission grating spectrometer is most consistent with a cooling flow model, placing V426 Oph among the group of CVs including U Gem and EX Hya. An uninterrupted light curve was also constructed, in which we detect a significant 4.2 hr modulation together with its first harmonic at 2.1 hr. Reanalysis of archival Ginga and ROSAT X-ray light curves also reveals modulations at periods consistent with 4.2 and/or 2.1 hr. Furthermore, optical photometry in V, simultaneous with the Chandra observation, indicates a modulation anticorrelated with the X-ray, and later more extensive R-band photometry finds a signal at ~2.1 hr. The earlier reported X-ray periods at ~0.5 and 1 hr appear to be only transient and quasi-periodic in nature. In contrast, the 4.2 hr period or its harmonic is stable and persistent in X-ray/optical data from 1988 to 2003. This periodicity is clearly distinct from the 6.85 hr orbit and could be due to the spin of the white dwarf. If this is the case, V426 Oph would be the first long-period intermediate polar with a ratio Pspin/Porb of 0.6. However, this interpretation requires unreasonable values of magnetic field strength and mass accretion rate. Title: VizieR Online Data Catalog: Catalog of white dwarfs in SDSS-DR1 (Kleinman+, 2004) Authors: Kleinman, S. J.; Harris, H. C.; Eisenstein, D. J.; Liebert, J.; Nitta, A.; Krzesinski, J.; Munn, J. A.; Dahn, C. C.; Hawley, S. L.; Pier, J. R.; Schmidt, G.; Silvestri, N. M.; Smith, J. A.; Szkody, P.; Strauss, M. A.; Knapp, G. R.; Collinge, M. J.; Mukadam, A. S.; Koester, D.; Uomoto, A.; Schlegel, D. J.; Anderson, S. F.; Brinkmann, J.; Lamb, D. Q.; Schneider, D. P.; York, D. G. Bibcode: 2004yCat..16070426K Altcode: We present the full spectroscopic white dwarf and hot subdwarf sample from the Sloan Digital Sky Survey (SDSS) First Data Release, DR1. We find 2551 white dwarf stars of various types, 240 hot subdwarf stars, and an additional 144 objects we have identified as uncertain white dwarf stars. Of the white dwarf stars, 1888 are nonmagnetic DA types and 171 are nonmagnetic DBs. The remaining (492) objects consist of all different types of white dwarf stars: DO, DQ, DC, DH, DZ, hybrid stars such as DAB, etc., and those with nondegenerate companions. We fit the DA and DB spectra with a grid of models to determine the Teff and logg for each object. For all objects, we provide coordinates, proper motions, SDSS photometric magnitudes, and enough information to retrieve the spectrum/image from the SDSS public database. This catalog nearly doubles the known sample of spectroscopically identified white dwarf stars. In the DR1 imaged area of the sky, we increase the known sample of white dwarf stars by a factor of 8.5. We also comment on several particularly interesting objects in this sample.

(6 data files). Title: Spectroscopic Properties of Cool Stars in the Sloan Digital Sky Survey: An Analysis of Magnetic Activity and a Search for Subdwarfs Authors: West, Andrew A.; Hawley, Suzanne L.; Walkowicz, Lucianne M.; Covey, Kevin R.; Silvestri, Nicole M.; Raymond, Sean N.; Harris, Hugh C.; Munn, Jeffrey A.; McGehee, Peregrine M.; Ivezić, Željko; Brinkmann, J. Bibcode: 2004AJ....128..426W Altcode: 2004astro.ph..3486W We present a spectroscopic analysis of nearly 8000 late-type dwarfs in the Sloan Digital Sky Survey. Using the Hα emission line as an activity indicator, we investigate the fraction of active stars as a function of spectral type and find a peak near type M8, confirming previous results. In contrast to past findings, we find that not all M7-M8 stars are active. We show that this may be a selection effect of the distance distributions of previous samples, since the active stars appear to be concentrated near the Galactic plane. We also examine the activity strength (ratio of the luminosity emitted in Hα to the bolometric luminosity) for each star and find that the mean activity strength is constant over the range M0-M5 and declines at later types. The decline begins at a slightly earlier spectral type than previously found. We explore the effect that activity has on the broadband photometric colors and find no significant differences between active and inactive stars. We also carry out a search for subdwarfs using spectroscopic metallicity indicators and find 60 subdwarf candidates. Several of these candidates are near the extreme subdwarf boundary. The spectroscopic subdwarf candidates are redder by ~0.2 mag in g-r compared with disk dwarfs at the same r-i color. Title: Cataclysmic Variables from SDSS III. The Third Year Authors: Szkody, Paula; Henden, Arne; Fraser, Oliver; Silvestri, Nicole; Bochanski, John; Wolfe, Michael A.; Agüeros, Marcel; Warner, Brian; Woudt, Patrick; Tramposch, Jonica; Homer, Lee; Schmidt, Gary; Knapp, Gillian R.; Anderson, Scott F.; Covey, Kevin; Harris, Hugh; Hawley, Suzanne; Schneider, Donald P.; Voges, Wolfgang; Brinkmann, J. Bibcode: 2004astro.ph..7071S Altcode: This paper continues the series that identifies new cataclysmic variables found in the Sloan Digital Sky Survey. We present 36 cataclysmic variables and one possible symbiotic star from Sloan spectra obtained during 2002, of which 34 are new discoveries, 2 are known dwarf novae (BC UMa, KS UMa) and one is a known CV identified from the 2dF survey. The positions, colors and spectra of all 37 systems are presented, along with follow-up spectroscopic/photometric observations of 10 systems. As in the past 2 years of data, the new SDSS systems show a large variety of characteristics based on their inclination and magnetic fields, including 3 eclipsing systems, 4 with prominent He II emission, and 15 systems showing features of the underlying stars. Title: Meeting the Cool Neighbors. VIII. A Preliminary 20 Parsec Census from the NLTT Catalogue Authors: Reid, I. Neill; Cruz, Kelle L.; Allen, Peter; Mungall, F.; Kilkenny, D.; Liebert, James; Hawley, Suzanne L.; Fraser, Oliver J.; Covey, Kevin R.; Lowrance, Patrick; Kirkpatrick, J. Davy; Burgasser, Adam J. Bibcode: 2004AJ....128..463R Altcode: 2004astro.ph..4061R Continuing our census of late-type dwarfs in the solar neighborhood, we present BVRI photometry and optical spectroscopy of 800 mid-type M dwarfs drawn from the NLTT proper-motion catalog. The targets are taken both from our own cross-referencing of the NLTT Catalogue and the 2MASS Second Incremental Data Release, and from the revised NLTT compiled recently by Salim & Gould. All are identified as nearby-star candidates based on their location in the (mr,mr-Ks) diagram. Three hundred stars discussed here have previous astrometric, photometric, or spectroscopic observations. We present new BVRI photometry for 101 stars, together with low-resolution spectroscopy of a further 400 dwarfs. In total, we find that 241 stars are within 20 pc of the Sun, while a further 70 lie within 1 σ of our distance limit. Combining the present results with previous analyses, we have quantitative observations for 1910 of the 1913 candidates in our NLTT nearby-star samples. Eight hundred fifteen of those stars have distance estimates of 20 pc or less, including 312 additions to the local census. With our NLTT follow-up observations essentially complete, we have searched the literature for K and early-type M dwarfs within the sampling volume covered by the 2MASS second release. Comparing the resultant 20 pc census against predicted numbers, derived from the 8 pc luminosity function, shows an overall deficit of ~20% for stellar systems and ~35% for individual stars. Almost all are likely to be fainter than MJ=7, and at least half are probably as yet undiscovered companions of known nearby stars. Our results suggest that there are relatively few missing systems at the lowest luminosities, MJ>8.5. We discuss possible means of identifying the missing stars. Title: Investigation of M Dwarf Atmospheres Using Archival STIS Data Authors: Hawley, Suzanne Bibcode: 2004hst..prop10312H Altcode: 2004hst..prop.6630H We propose an archival study of the STIS/MAMA data from program GO-8129. The data comprise the only high-resolution, near-ultraviolet spectra in the HST archive, and indeed in existence, for an M dwarf. We will analyze the six orbits of data to find periods of quiescence {between obvious flares}, and will produce a high signal-to-noise ratio summed quiescent spectrum for analysis. Using the CHIANTI database together with detailed radiative hydrodynamic models, we will investigate the outer atmospheric structure of active M dwarfs. Employing hundreds of lines in the archival spectrum as constraints, we will construct the first self-consistent model of an M dwarf atmosphere. Title: Chandra X-ray results on V426 Ophiuchi Authors: Homer, L.; Szkody, P.; Raymond, J. C.; Fried, R. E.; Hoard, D. W.; Hawley, S. L.; Wolfe, M.; Tramposch, J. N.; Yirak, K. T. Bibcode: 2004RMxAC..20..176H Altcode: 2004IAUCo.194..176H From a 45ks Chandra observation of V426 Oph we have obtained high-resolution X-ray spectra at moderate signal-to-noise, and a good quality, uninterrupted lightcurve. The spectra are reasonably fit with a cooling flow model, similar to EX Hya and U Gem. Our analysis of the Chandra and additional X-ray/optical lightcurves reveals a persistent modulation at 4.2 hr from 1988 to 2003, likely the white dwarf spin period indicating an intermediate polar nature for V426 Oph. Title: Radiative Hydrodynamic Simulations of Solar and Stellar Flares Authors: Allred, J. C.; Hawley, S. L.; Abbett, W. P. Bibcode: 2004AAS...204.0305A Altcode: 2004BAAS...36..671A We have constructed radiative hydrodynamic simulations of the effects of flare heating on model solar and dMe stellar atmospheres. The heating is assumed to be driven by a beam of non-thermal electrons originating in the corona and impacting on the lower transition region and chromosphere. We use thick target bremsstrahlung fits to RHESSI hard X-ray observations of the July 23, 2002 and February 26, 2002 flares to model the electron beam. Our simulations include detailed calculations of numerous bound-bound and bound-free transitions which we compare with line profiles measured during flares on the Sun and on the dMe star AD Leo. We also investigate the possibility that the 511 keV emission line is produced from a significant amount of material at transition region temperatures. Title: A Strategy for Finding Near-Earth Objects with the SDSS Telescope Authors: Raymond, Sean N.; Miknaitis, Gajus; Fraser, Oliver J.; Garg, Arti; Hawley, Suzanne L.; Jedicke, Robert; Quinn, Thomas; Rockosi, Constance M.; Stubbs, Christopher W.; Anderson, Scott F.; Hogan, Craig J.; Ivezić, Željko; Lupton, Robert H.; West, Andrew A.; Brewington, Howard; Brinkmann, J.; Harvanek, Michael; Kleinman, Scot J.; Krzesiński, Jurek; Long, Dan; Neilsen, Eric H.; Newman, Peter R.; Nitta, Atsuko; Snedden, Stephanie A. Bibcode: 2004AJ....127.2978R Altcode: 2004astro.ph..1438R We present a detailed observational strategy for finding near-Earth objects (NEOs) with the Sloan Digital Sky Survey (SDSS) telescope. We investigate strategies in normal, unbinned mode, as well as binning the CCDs 2×2 or 3×3, which affects the sky coverage rate and the limiting apparent magnitude. We present results from 1 month, 3 year, and 10 year simulations of such surveys. For each cadence and binning mode, we evaluate the possibility of achieving the Spaceguard goal of detecting 90% of 1 km NEOs (absolute magnitude H<=18 for an albedo of 0.1). We find that an unbinned survey is most effective at detecting H<=20 NEOs in our sample. However, a 3×3 binned survey reaches the Spaceguard goal after only 7 years of operation. As the proposed large survey telescopes (Pan-STARRS, LSST) are at least 5-10 years from operation, an SDSS NEO survey could make a significant contribution to the detection and photometric characterization of the NEO population. Title: Spectroscopic Properties of Cool Stars in the SDSS Authors: Hawley, S. L.; West, A. A.; Walkowicz, L. M.; Covey, K. R. Bibcode: 2004AAS...204.0307H Altcode: 2004BAAS...36..672H We present a spectroscopic analysis of nearly 8000 late-type dwarfs in the Sloan Digital Sky Survey. Using the H-alpha emission line as an activity indicator, we investigate the fraction of active stars as a function of spectral type and find a peak near type M8, confirming previous results. In contrast to past findings, we find that not all M7-M8 stars are active. We show that this may be a selection effect of the distance distributions of previous samples, as the active stars appear to be concentrated near the Galactic Plane. We also examine the activity strength (ratio of the luminosity emitted in H-alpha to the bolometric luminosity) for each star, and find that the mean activity strength is constant over the range M0-M5 and declines at later types. The decline begins at a slightly earlier spectral type than previously found. We explore the effect that activity has on the broadband photometric colors and find no significant differences between active and inactive stars. We also carry out a search for subdwarfs using spectroscopic metallicity indicators, and find 60 subdwarf candidates. Several of these candidates are near the extreme subdwarf boundary. The spectroscopic subdwarf candidates are redder by approx. 0.2 magnitudes in (g-r) compared to disk dwarfs at the same (r-i) color.

A paper describing these results is scheduled for the June 2004 issue of the Astronomical Journal. This work is supported by NSF grant AST 02-05875. Title: A Catalog of Spectroscopically Identified White Dwarf Stars in the First Data Release of the Sloan Digital Sky Survey Authors: Kleinman, S. J.; Harris, Hugh C.; Eisenstein, Daniel J.; Liebert, James; Nitta, Atsuko; Krzesiński, Jurek; Munn, Jeffrey A.; Dahn, Conard C.; Hawley, Suzanne L.; Pier, Jeffrey R.; Schmidt, Gary; Silvestri, Nicole M.; Smith, J. Allyn; Szkody, Paula; Strauss, Michael A.; Knapp, G. R.; Collinge, Matthew J.; Mukadam, A. S.; Koester, D.; Uomoto, Alan; Schlegel, D. J.; Anderson, Scott F.; Brinkmann, J.; Lamb, D. Q.; Schneider, Donald P.; York, Donald G. Bibcode: 2004ApJ...607..426K Altcode: 2004astro.ph..2209K We present the full spectroscopic white dwarf and hot subdwarf sample from the Sloan Digital Sky Survey (SDSS) first data release, DR1. We find 2551 white dwarf stars of various types, 240 hot subdwarf stars, and an additional 144 objects we have identified as uncertain white dwarf stars. Of the white dwarf stars, 1888 are nonmagnetic DA types and 171 are nonmagnetic DBs. The remaining (492) objects consist of all different types of white dwarf stars: DO, DQ, DC, DH, DZ, hybrid stars such as DAB, etc., and those with nondegenerate companions. We fit the DA and DB spectra with a grid of models to determine the Teff and logg for each object. For all objects, we provide coordinates, proper motions, SDSS photometric magnitudes, and enough information to retrieve the spectrum/image from the SDSS public database. This catalog nearly doubles the known sample of spectroscopically identified white dwarf stars. In the DR1 imaged area of the sky, we increase the known sample of white dwarf stars by a factor of 8.5. We also comment on several particularly interesting objects in this sample. Title: Persistent Transition Region Emission in Very Low Mass Stars Authors: Hawley, S. L.; Johns-Krull, C. M. Bibcode: 2004IAUS..219..306H Altcode: 2003IAUS..219E.216H We present results from our cycle 10 HST program to search for transition region emission in very low-mass main-sequence stars in the spectral range M7-M9. flaring and quiescent origin for the emission. We have obtained HST/STIS time series observations of three active very low mass stars (VB 8 VB 10 and LHS 2065) which show persistent activity in transition region lines including C IV Si IV and He II. The emission in these transition region lines is variable between exposures but is always observed. A strong flare was observed in one 10 minute exposure on VB 10. Our results indicate that active very low-mass stars maintain a persistent quiescent chromosphere and transition region that is similar to those observed in active earlier type M dwarfs in contrast to suggestions that these low-mass main-sequence stars exhibit only flaring activity. Title: Magnetic Activity in Low Mass Stars: SDSS Results Authors: West, A. A.; Hawley, S. L.; Walkowicz, L. M.; Covey, K. R. Bibcode: 2004IAUS..219..935W Altcode: 2003IAUS..219E.232W We present a study of the magnetic activity properties of low-mass stars in the Sloan Digital Sky Survey. Using the H-alpha emission line as an activity indicator we examine the fraction of active stars as a function of spectral type and find a peak near type M7 confirming previous results. However contrary to past findings we find that not all M7 stars are active. We investigate the ratio of the luminosity emitted in H-alpha compared to the bolometric luminosity for each star and find a roughly constant ratio (with large scatter) over the range M0-M7. There appears to be a slight decrease in this ratio for types M8-L0 in agreement with previous determinations. We also explore the effect of metallicity on activity and examine whether activity is correlated with changes in SDSS colors. Title: Multi-Wavelength Observations of EV Lacertae Authors: Osten, R. A.; Hawley, S. L.; Allred, J.; Johns-Krull, C. M.; Roark, C.; Ambruster, C.; Brown, A.; Ayres, T. R.; Linsky, J. L. Bibcode: 2004IAUS..219..249O Altcode: 2003IAUS..219E.207O We present an analysis of simultaneous radio optical UV and X-ray observations of the dMe flare star EV Lacertae taken in 2001 September. The analysis is time-resolved and concentrates on determining flare-related changes in each spectral region. Temporal correlations in different wavelength regions are examined. Numerous X-ray flares were observed; two X-ray flares are accompanied by UV enhancements in a pattern reminiscent of the Neupert effect seen in solar flares where UV bursts are interpreted as a product of nonthermal heat input to the lower atmosphere and soft X-ray emission occurs as a result of the heating. An extemely large radio flare seen at two frequencies and representing a factor of 100 increase in quiescent radio flux density has an optical counterpart with an enhancement of about 3 magnitudes in the U filter. There is no corresponding increase in soft X-ray flux. We investigate scenarios which could give rise to the observed multi-wavelength correlations. The run of electron density with temperature in the outer atmosphere (transition region through corona) is investigated and implications for coronal structure are given. Title: HST, EUVE and Ground-Based Observations of Flares on AD Leo Authors: Allred, J. C.; Hawley, S. L.; Johns-Krull, C. M.; Fisher, G. H.; Abbett, W. P.; Avgoloupis, S. I.; Seiradakis, J. H. Bibcode: 2004IAUS..219..829A Altcode: No abstract at ADS Title: VizieR Online Data Catalog: Spectroscopy of faint red NLTT dwarfs (Reid+, 2003) Authors: Reid, I. N.; Cruz, K. L.; Allen, P.; Mungall, F.; Kilkenny, D.; Liebert, J.; Hawley, S. L.; Fraser, O. J.; Covey, K. R.; Lowrance, P. Bibcode: 2004yCat..51263007R Altcode: We present low-resolution optical spectroscopy and BVRI photometry of 453 candidate nearby stars drawn from the NLTT (<I/98>) proper-motion catalog. The stars were selected based on optical/near-infrared colors, derived by combining the NLTT photographic data with photometry from the 2MASS Second Incremental Data Release (<II/241>). Based on the derived photometric and spectroscopic parallaxes, we identify 111 stars as lying within 20pc of the Sun, including nine stars with formal distance estimates of less than 10pc. A further 53 stars have distance estimates within 1σ of our 20pc limit. Almost all of those stars are additions to the nearby-star census. In total, our NLTT-based survey has so far identified 496 stars likely to be within 20pc, of which 195 are additions to nearby-star catalogs. Most of the newly identified nearby stars have spectral types between M4 and M8.

(5 data files). Title: Recent Advances in Understanding Star and Planet Formation Authors: Reid, I. N.; Hawley, S. L. Bibcode: 2004autt.book....1R Altcode: No abstract at ADS Title: Meeting the Cool Neighbors. VII. Spectroscopy of Faint Red NLTT Dwarfs Authors: Reid, I. Neill; Cruz, Kelle L.; Allen, Peter; Mungall, F.; Kilkenny, D.; Liebert, James; Hawley, Suzanne L.; Fraser, Oliver J.; Covey, Kevin R.; Lowrance, Patrick Bibcode: 2003AJ....126.3007R Altcode: 2003astro.ph..8380R We present low-resolution optical spectroscopy and BVRI photometry of 453 candidate nearby stars drawn from the NLTT proper-motion catalog. The stars were selected based on optical/near-infrared colors, derived by combining the NLTT photographic data with photometry from the 2MASS Second Incremental Data Release. Based on the derived photometric and spectroscopic parallaxes, we identify 111 stars as lying within 20 pc of the Sun, including nine stars with formal distance estimates of less than 10 pc. A further 53 stars have distance estimates within 1 σ of our 20 pc limit. Almost all of those stars are additions to the nearby-star census. In total, our NLTT-based survey has so far identified 496 stars likely to be within 20 pc, of which 195 are additions to nearby-star catalogs. Most of the newly identified nearby stars have spectral types between M4 and M8. Title: Identification of Low Mass T Tauri Candidates at High Galactic Latitudes Authors: McGehee, P. M.; Hawley, S. L.; Ivezic, Z. Bibcode: 2003AAS...203.0510M Altcode: 2003BAAS...35Q1211M We present an optical study of low mass stars at high galactic latitudes (|b| > 30) using Sloan Digital Sky Survey (SDSS) imaging and spectroscopy. We specifically target stars whose SDSS colors indicate a M dwarf spectral type which, for objects having ages between 1 and 10 Myr, corresponds to masses less than 0.8 solar. Analysis of SDSS data obtained in the Orion OB1b and Taurus Star Formation Regions shows that actively accreting young stars have (u-g, g-r) colors distinct from those of the white dwarf - M dwarf pairs that dominate the field ultraviolet excess low mass star population. Furthermore, we find that this separation can be drawn using the reddening-invariant index formed by u-g and g-r, thus enabling selection of low mass Classical T Tauri candidates without correction for extinction. The spatial distribution of candidates is analyzed with emphasis on their relation to high latitude molecular clouds. Title: Spectroscopic Calibrations for the SDSS/2MASS Low Mass Luminosity Function Authors: Covey, K. R.; Hawley, S. L.; Sloan Digital Sky Survey Collaboration Bibcode: 2003AAS...203.4301C Altcode: 2003BAAS...35.1272C The photometric precision and overwhelming size of the SDSS and 2MASS databases lend themselves to large statistical studies of astronomical objects. One such project is currently underway, correlating detections of low mass stars in both databases and making use of photometric parallax relations to construct a luminosity function for late type stars. However, a sample constructed from photometric identifications alone must be carefully corrected for bias, incompleteness, and contamination. We describe an ongoing observational campaign to calibrate the extent of these effects, and present early indications of the reliability of the relationships with which low mass dwarfs can be targeted from photometric detections in the SDSS and 2MASS databases.

The authors gratefully acknowledge support of this work from NASA ADP grant NAG5-13111. Title: Radiative Hydrodynamic Models of Solar White Light Flares Authors: Allred, J. C.; Hawley, S. L.; Abbett, W. P.; Fisher, G. H.; Hudson, H. S.; Metcalf, T. R. Bibcode: 2003AGUFMSH22A0175A Altcode: We report on theoretical radiative hydrodynamic simulations of solar white light flares. The solar atmosphere is modeled in detail from the transition region to the photosphere. The coronal pressure and X-ray backheating are included self-consistently. Flare heating is assumed to be from an electron beam which is modeled for several white light flares using data from RHESSI, TRACE and Yohkoh. We also investigate the possibility that the 511 keV line width is produced from a significant column depth of atmosphere at transition region temperatures. We compare our new solar flare models to previous results, and to models of M dwarf stellar flares. Title: Quasar Outburst in Mensa Authors: Clocchiatti, A.; Minitti, D.; Aguilera, C.; Becker, A.; Cook, K.; Covarrubias, R.; Hawley, S.; Hiriart, R.; Keller, S.; Miceli, A.; Miknaitis, G.; Nikolaev, S.; Olsen, K.; Prieto, J.; Proctor, G.; Rest, A.; Schmidt, B.; Smith, C.; Stubbs, C.; Suntzeff, N.; Welch, D. Bibcode: 2003IAUC.8258....1C Altcode: 2003IAUC.8258A...1C A. Clocchiatti and D. Minitti, Pontificia Universidad Catolica de Chile, on behalf of the SuperMACHO project (involving also C. Aguilera, A. Becker, K. Cook, R. Covarrubias, S. Hawley, R. Hiriart, S. Keller, A. Miceli, G. Miknaitis, S. Nikolaev, K. Olsen, J. Prieto, G. Proctor, A. Rest, B. Schmidt, C. Smith, C. Stubbs, N. Suntzeff, and D. Welch), report the discovery of a highly unusual outburst of a quasistellar object (QSO) at z = 2.87. The object, located at R.A. = 5h13m03s.94, Decl. = -70o22'50".5 (equinox 2000.0), had a quiescent broadband magnitude of VR approximately 22.2. Multiple broadband-VR-filter images taken at the Blanco 4-m telescope at Cerro Tololo reveal no significant change in brightness from the beginning of observations in 2001 Sept. until 2003 Sept. 27 UT, around the date that it began to brighten linearly in flux with time. By Dec. 15, it had brightened by a factor of 15 and has reached VR = 19.4 with no evidence of a change in trend. Identified as a SuperMACHO microlensing candidate, follow-up spectroscopy (456-s exposure) was obtained at the Magellan II (Clay) 6.5-m telescope (+ LDSS2 spectrograph with medium-blue grism) on Dec. 3.8. The spectrum reveals several prominent QSO lines with strong P-Cyg profiles, indicative of an ejection velocity of 1600 km/s; identified features include H (Lyman-alpha), N V, C IV 154.9-nm, Si IV 139.3-nm, O IV, and [C III] 191.0-nm. The high redshift, extreme current luminosity, evidence of outflow (from P-Cyg line profiles), and continued brightening suggest that this is an object worthy of intense monitoring. Title: White Dwarf-M Dwarf Close Binary Systems in the Sloan Digital Sky Survey Authors: Silvestri, N. M.; Hawley, S. L.; Szkody, P.; SDSS Collaboration Bibcode: 2003AAS...203.4201S Altcode: 2003BAAS...35.1271S Using photometric colors and spectra, we have identified over 400 white dwarf-M dwarf close binary systems in the SDSS database. We are in the process of performing followup observations of systems with the strongest Balmer emission on the ARC 3.5-m telescope as we suspect these pairs may be in a pre-cataclysmic variable phase of evolution. There has been much emphasis on the evolution of the white dwarf in these systems, but it is not really known how the binary environment influences the evolution of the M dwarf and whether the properties of the M dwarf are impacted by the presence of a white dwarf companion. From the followup spectroscopy, we have determined the physical properties of the M dwarf, the temperature, spectral type and rough age estimate of the white dwarf as well as the radial velocity and orbital period for several of these close binary systems. The physical properties and activity of the M dwarf and influence of the pre-CV system on M dwarf evolution are discussed.

This work is supported in part by NSF Grant AST02-05875. Title: Multiwavelength Observations of Flares on AD Leonis Authors: Hawley, Suzanne L.; Allred, Joel C.; Johns-Krull, Christopher M.; Fisher, George H.; Abbett, William P.; Alekseev, Ilya; Avgoloupis, Stavros I.; Deustua, Susana E.; Gunn, Alastair; Seiradakis, John H.; Sirk, Martin M.; Valenti, Jeff A. Bibcode: 2003ApJ...597..535H Altcode: We report results from a multiwavelength observing campaign conducted during 2000 March on the flare star AD Leo. Simultaneous data were obtained from several ground- and space-based observatories, including observations of eight sizable flares. We discuss the correlation of line and continuum emission in the optical and ultraviolet wavelength regimes, as well as the flare energy budget, and we find that the emission properties are remarkably similar even for flares of very different evolutionary morphology. This suggests a common heating mechanism and atmospheric structure that are independent of the detailed evolution of individual flares. We also discuss the Neupert effect, chromospheric line broadening, and velocity fields observed in several transition region emission lines. The latter show significant downflows during and shortly after the flare impulsive phase. Our observations are broadly consistent with the solar model of chromospheric evaporation and condensation following impulsive heating by a flux of nonthermal electrons. These data place strong constraints on the next generation of radiative hydrodynamic models of stellar flares. Title: SDSS White Dwarfs with Spectra Showing Atomic Oxygen and/or Carbon Lines Authors: Liebert, James; Harris, H. C.; Dahn, C. C.; Schmidt, Gary D.; Kleinman, S. J.; Nitta, Atsuko; Krzesiński, Jurek; Eisenstein, Daniel; Smith, J. Allyn; Szkody, Paula; Hawley, Suzanne; Anderson, Scott F.; Brinkmann, J.; Collinge, Matthew J.; Fan, Xiaohui; Hall, Patrick B.; Knapp, Gillian R.; Lamb, Don Q.; Margon, B.; Schneider, Donald P.; Silvestri, Nicole Bibcode: 2003AJ....126.2521L Altcode: We discuss 18 white dwarfs, one of which (G227-5) was previously known, whose SDSS spectra show lines of neutral and/or singly ionized carbon. At least two and perhaps four show lines of neutral or singly ionized oxygen. Apart from the extremely hot ``PG 1159'' stars, these are the first white dwarfs with photospheric oxygen detected in their optical spectra. The photometry strongly suggests that these stars lie in the 11,000-30,000 K temperature range of the helium-atmosphere DB white dwarfs, though only one of them shows weak neutral helium lines in the spectrum. Trigonometric parallaxes are known for G227-5 and another, previously known white dwarf (G35-26) showing atomic carbon lines, and they indicate that both are massive stars. Theoretical arguments suggest that all members of this class of rare white dwarfs are massive (~1 Msolar), and this finding could explain the paucity of massive DB white dwarfs. Title: An Insider's View of Brown Dwarfs Authors: Hawley, S. L. Bibcode: 2003csss...12...97H Altcode: This review seeks to provide the background material necessary to understand the newest developments in the study of brown dwarfs. I describe the physical and observational properties of low mass stars and brown dwarfs, and discuss our ability to distinguish between them. Other topics include atmospheric variability in the form of magnetic activity and weather, and the mass function and local density of brown dwarfs in the solar neighborhood. The connection between brown dwarfs and planets will be covered in the companion review paper on extrasolar planets. Title: The First Data Release of the Sloan Digital Sky Survey Authors: Abazajian, Kevork; Adelman-McCarthy, Jennifer K.; Agüeros, Marcel A.; Allam, Sahar S.; Anderson, Scott F.; Annis, James; Bahcall, Neta A.; Baldry, Ivan K.; Bastian, Steven; Berlind, Andreas; Bernardi, Mariangela; Blanton, Michael R.; Blythe, Norman; Bochanski, John J., Jr.; Boroski, William N.; Brewington, Howard; Briggs, John W.; Brinkmann, J.; Brunner, Robert J.; Budavári, Tamás; Carey, Larry N.; Carr, Michael A.; Castander, Francisco J.; Chiu, Kuenley; Collinge, Matthew J.; Connolly, A. J.; Covey, Kevin R.; Csabai, István; Dalcanton, Julianne J.; Dodelson, Scott; Doi, Mamoru; Dong, Feng; Eisenstein, Daniel J.; Evans, Michael L.; Fan, Xiaohui; Feldman, Paul D.; Finkbeiner, Douglas P.; Friedman, Scott D.; Frieman, Joshua A.; Fukugita, Masataka; Gal, Roy R.; Gillespie, Bruce; Glazebrook, Karl; Gonzalez, Carlos F.; Gray, Jim; Grebel, Eva K.; Grodnicki, Lauren; Gunn, James E.; Gurbani, Vijay K.; Hall, Patrick B.; Hao, Lei; Harbeck, Daniel; Harris, Frederick H.; Harris, Hugh C.; Harvanek, Michael; Hawley, Suzanne L.; Heckman, Timothy M.; Helmboldt, J. F.; Hendry, John S.; Hennessy, Gregory S.; Hindsley, Robert B.; Hogg, David W.; Holmgren, Donald J.; Holtzman, Jon A.; Homer, Lee; Hui, Lam; Ichikawa, Shin-ichi; Ichikawa, Takashi; Inkmann, John P.; Ivezić, Željko; Jester, Sebastian; Johnston, David E.; Jordan, Beatrice; Jordan, Wendell P.; Jorgensen, Anders M.; Jurić, Mario; Kauffmann, Guinevere; Kent, Stephen M.; Kleinman, S. J.; Knapp, G. R.; Kniazev, Alexei Y.; Kron, Richard G.; Krzesiński, Jurek; Kunszt, Peter Z.; Kuropatkin, Nickolai; Lamb, Donald Q.; Lampeitl, Hubert; Laubscher, Bryan E.; Lee, Brian C.; Leger, R. French; Li, Nolan; Lidz, Adam; Lin, Huan; Loh, Yeong-Shang; Long, Daniel C.; Loveday, Jon; Lupton, Robert H.; Malik, Tanu; Margon, Bruce; McGehee, Peregrine M.; McKay, Timothy A.; Meiksin, Avery; Miknaitis, Gajus A.; Moorthy, Bhasker K.; Munn, Jeffrey A.; Murphy, Tara; Nakajima, Reiko; Narayanan, Vijay K.; Nash, Thomas; Neilsen, Eric H., Jr.; Newberg, Heidi Jo; Newman, Peter R.; Nichol, Robert C.; Nicinski, Tom; Nieto-Santisteban, Maria; Nitta, Atsuko; Odenkirchen, Michael; Okamura, Sadanori; Ostriker, Jeremiah P.; Owen, Russell; Padmanabhan, Nikhil; Peoples, John; Pier, Jeffrey R.; Pindor, Bartosz; Pope, Adrian C.; Quinn, Thomas R.; Rafikov, R. R.; Raymond, Sean N.; Richards, Gordon T.; Richmond, Michael W.; Rix, Hans-Walter; Rockosi, Constance M.; Schaye, Joop; Schlegel, David J.; Schneider, Donald P.; Schroeder, Joshua; Scranton, Ryan; Sekiguchi, Maki; Seljak, Uroš; Sergey, Gary; Sesar, Branimir; Sheldon, Erin; Shimasaku, Kazu; Siegmund, Walter A.; Silvestri, Nicole M.; Sinisgalli, Allan J.; Sirko, Edwin; Smith, J. Allyn; Smolčić, Vernesa; Snedden, Stephanie A.; Stebbins, Albert; Steinhardt, Charles; Stinson, Gregory; Stoughton, Chris; Strateva, Iskra V.; Strauss, Michael A.; SubbaRao, Mark; Szalay, Alexander S.; Szapudi, István; Szkody, Paula; Tasca, Lidia; Tegmark, Max; Thakar, Aniruddha R.; Tremonti, Christy; Tucker, Douglas L.; Uomoto, Alan; Vanden Berk, Daniel E.; Vandenberg, Jan; Vogeley, Michael S.; Voges, Wolfgang; Vogt, Nicole P.; Walkowicz, Lucianne M.; Weinberg, David H.; West, Andrew A.; White, Simon D. M.; Wilhite, Brian C.; Willman, Beth; Xu, Yongzhong; Yanny, Brian; Yarger, Jean; Yasuda, Naoki; Yip, Ching-Wa; Yocum, D. R.; York, Donald G.; Zakamska, Nadia L.; Zehavi, Idit; Zheng, Wei; Zibetti, Stefano; Zucker, Daniel B. Bibcode: 2003AJ....126.2081A Altcode: 2003astro.ph..5492C; 2003astro.ph..5492T The Sloan Digital Sky Survey (SDSS) has validated and made publicly available its First Data Release. This consists of 2099 deg2 of five-band (u,g,r,i,z) imaging data, 186,240 spectra of galaxies, quasars, stars and calibrating blank sky patches selected over 1360 deg2 of this area, and tables of measured parameters from these data. The imaging data go to a depth of r~22.6 and are photometrically and astrometrically calibrated to 2% rms and 100 mas rms per coordinate, respectively. The spectra cover the range 3800-9200 Å, with a resolution of 1800-2100. This paper describes the characteristics of the data with emphasis on improvements since the release of commissioning data (the SDSS Early Data Release) and serves as a pointer to extensive published and on-line documentation of the survey. Title: An Outsiders View of Extrasolar Planets Authors: Hawley, S. L.; Reid, I. N. Bibcode: 2003csss...12..128H Altcode: We summarize the current state of extrasolar planet research, including the newest discoveries, properties of planetary systems, the current census, the mass function, and some thoughts on the formation and evolution of planetary disks. Title: The March 2000 AD Leo Flare Campaign Authors: Hawley, S. L.; Johns-Krull, C. M.; Fisher, G. H.; Abbett, W. P.; Seiradakis, J. H.; Avgoloupis, S. I. Bibcode: 2003csss...12..975H Altcode: Flares are by their nature random and unpredictable events and flare observations are often the serendipitous result of programs designed for other scientific endeavors. Thus, few observations of flares covering multiple wavelength regimes, with both spectroscopic and photometric information, are available to test stellar flare models. Occasionally, a bold and reckless team will put together a flare campaign, employing suitable statistical arguments to convince the relevant telescope allocation committees that such a campaign will prove fruitful, while hoping desperately for the combination of clear weather, working instruments and cooperative star necessary to warrant the herculean organizational effort. We report here on one such campaign, conducted during March, 2000 on the dM3e flare star AD Leo. Title: White Dwarf - M Dwarf Pairs in the Sloan Digital Sky Survey (SDSS) Authors: Raymond, S. N.; Szkody, P.; Hawley, S. L. Bibcode: 2003csss...12..992R Altcode: Using spectra and color cuts in the Sloan filter system, we have identified 83 White Dwarf - M dwarf pairs in the Sloan Digital Sky Survey (SDSS). The blue portion of the spectrum is fit with white dwarf models as a function of temperature. The best fit is then subtracted off to extract the M-dwarf spectrum. Many of these objects show strong Hα emission, an indicator of M-dwarf chromospheric activity. We have extracted a list of white dwarf temperatures, M-dwarf spectral types, and Hα equivalent widths, and we compare the activity level of these irradiated systems with the field M star population. If a portion of this activity is due to irradiation from the white dwarf companion, then we are studying binaries at a wide range in separations, from loosely bound systems to close binary pre-CVs. This hypothesis is being tested with a spectroscopic follow-up of SDSS objects by looking for (orbital) periodicity in the systems with the highest activity levels, using the ARC 3.5m telescope at Apache Point Observatory (APO). Title: New M and L Dwarfs Identified in the Sloan Digital Sky Survey Early Data Release Authors: Covey, K. R.; Hawley, S. L.; Knapp, G. R.; Anderson, S. F. Bibcode: 2003csss...12..658C Altcode: Spectra from the Sloan Digital Sky Survey (SDSS) Early Data Release (EDR) reveal 645 late-type (spectral type M and L) dwarfs. Additional SDSS spectra have been obtained of 34 L dwarfs from SDSS data not contained within the EDR. Stars were assigned spectral types from the spectral sequence of Kirkpatrick et al. (1999) using measurements of spectral indices and least squares fits to templates. Correlations between spectral type, optical (SDSS) and infrared (2MASS) colors are investigated. Title: Magnetic White Dwarfs from the Sloan Digital Sky Survey: The First Data Release Authors: Schmidt, Gary D.; Harris, Hugh C.; Liebert, James; Eisenstein, Daniel J.; Anderson, Scott F.; Brinkmann, J.; Hall, Patrick B.; Harvanek, Michael; Hawley, Suzanne; Kleinman, S. J.; Knapp, Gillian R.; Krzesinski, Jurek; Lamb, Don Q.; Long, Dan; Munn, Jeffrey A.; Neilsen, Eric H.; Newman, Peter R.; Nitta, Atsuko; Schlegel, David J.; Schneider, Donald P.; Silvestri, Nicole M.; Smith, J. Allyn; Snedden, Stephanie A.; Szkody, Paula; Vanden Berk, Dan Bibcode: 2003ApJ...595.1101S Altcode: 2003astro.ph..7121S Beyond its goals related to the extragalactic universe, the Sloan Digital Sky Survey (SDSS) is an effective tool for identifying stellar objects with unusual spectral energy distributions. Here we report on the 53 new magnetic white dwarfs discovered during the first two years of the survey, including 38 whose data are made public in the 1500 deg2 First Data Release. Discoveries span the magnitude range 16.3<=g<=20.5, and based on the recovery rate for previously known magnetic white dwarfs, the completeness of the SDSS appears to be high for reasonably hot stars with B>~3 MG and g>~15. The new objects nearly double the total number of known magnetic white dwarfs and include examples with polar field strengths Bp>500 MG, as well as several with exotic atmospheric compositions. The improved sample statistics and uniformity indicate that the distribution of magnetic white dwarfs has a broad peak in the range ~5-30 MG and a tail extending to nearly 109 G. Degenerates with polar fields Bp>~50 MG are consistent with being descendents of magnetic Ap/Bp main-sequence stars, but low- and moderate-field magnetic white dwarfs appear to imply another origin. Yet-undetected magnetic F-type stars with convective envelopes that destroy the ordered underlying field are attractive candidates.

A portion of the results presented here were obtained with the MMT Observatory, a facility operated jointly by the University of Arizona and the Smithsonian Institution. Title: Cataclysmic Variables from the Sloan Digital Sky Survey. II. The Second Year Authors: Szkody, Paula; Fraser, Oliver; Silvestri, Nicole; Henden, Arne; Anderson, Scott F.; Frith, James; Lawton, Brandon; Owens, Ethan; Raymond, Sean; Schmidt, Gary; Wolfe, Michael; Bochanski, John; Covey, Kevin; Harris, Hugh; Hawley, Suzanne; Knapp, Gillian R.; Margon, Bruce; Voges, Wolfgang; Walkowicz, Lucianne; Brinkmann, J.; Lamb, D. Q. Bibcode: 2003AJ....126.1499S Altcode: 2003astro.ph..6269S The first full year of operation following the commissioning year of the Sloan Digital Sky Survey (SDSS) has revealed a wide variety of newly discovered cataclysmic variables (CVs). We show the SDSS spectra of 42 CVs observed in 2002, of which 35 are new classifications, four are known dwarf novae (CT Hya, RZ Leo, T Leo, and BZ UMa), one is a known CV identified from a previous quasar survey (Aqr1), and two are known ROSAT or FIRST discovered CVs (RX J09445+0357, FIRST J102347.6+003841). The SDSS positions, colors, and spectra of all 42 systems are presented. In addition, the results of follow-up studies of several of these objects identify the orbital periods, velocity curves, and polarization that provide the system geometry and accretion properties. While most of the SDSS discovered systems are faint (greater than 18th magnitude) with low accretion rates (as implied from their spectral characteristics), there are also a few bright objects that may have escaped previous surveys due to changes in the mass transfer rate.

Based on observations obtained with the Sloan Digital Sky Survey and with the Apache Point Observatory 3.5 m telescope, which are owned and operated by the Astrophysical Research Consortium (ARC). Title: An Initial Survey of White Dwarfs in the Sloan Digital Sky Survey Authors: Harris, Hugh C.; Liebert, James; Kleinman, S. J.; Nitta, Atsuko; Anderson, Scott F.; Knapp, Gillian R.; Krzesiński, Jurek; Schmidt, Gary; Strauss, Michael A.; Vanden Berk, Dan; Eisenstein, Daniel; Hawley, Suzanne; Margon, Bruce; Munn, Jeffrey A.; Silvestri, Nicole M.; Smith, J. Allyn; Szkody, Paula; Collinge, Matthew J.; Dahn, Conard C.; Fan, Xiaohui; Hall, Patrick B.; Schneider, Donald P.; Brinkmann, J.; Burles, Scott; Gunn, James E.; Hennessy, Gregory S.; Hindsley, Robert; Ivezić, Zeljko; Kent, Stephen; Lamb, Donald Q.; Lupton, Robert H.; Nichol, R. C.; Pier, Jeffrey R.; Schlegel, David J.; SubbaRao, Mark; Uomoto, Alan; Yanny, Brian; York, Donald G. Bibcode: 2003AJ....126.1023H Altcode: 2003astro.ph..5347H An initial assessment is made of white dwarf and hot subdwarf stars observed in the Sloan Digital Sky Survey. In a small area of sky (190 square degrees), observed much like the full survey will be, 269 white dwarfs (WDs) and 56 hot subdwarfs are identified spectroscopically where only 44 white dwarfs and five hot subdwarfs were known previously. Most are ordinary DA (hydrogen atmosphere) and DB (helium) types. In addition, in the full survey to date, a number of WDs have been found with uncommon spectral types. Among these are blue DQ stars displaying lines of atomic carbon; red DQ stars showing molecular bands of C2 with a wide variety of strengths; DZ stars where Ca and occasionally Mg, Na, and/or Fe lines are detected; and magnetic WDs with a wide range of magnetic field strengths in DA, DB, DQ, and (probably) DZ spectral types. Photometry alone allows identification of stars hotter than 12,000 K, and the density of these stars for 15<g<20 is found to be ~2.2 deg-2 at Galactic latitudes of 29°-62°. Spectra are obtained for roughly half of these hot stars. The spectra show that for 15<g<17, 40% of hot stars are WDs, and the fraction of WDs rises to ~90% at g=20. The remainder are hot sdB and sdO stars. Title: Looking for Very Low-Mass Pre-Main Sequence Objects with SDSS Authors: McGehee, Peregrine M.; Hawley, Suzanne L.; Covey, Kevin R. Bibcode: 2003IAUS..211..525M Altcode: Determining the process(es) by which brown dwarfs form is key to understanding their intrinsic nature. If their origins are within circumstellar disks they are akin to giant planets. If, on the other hand, they coalesce from molecular cloud cores, then they share a common lineage with low mass stars. These two mechanisms can be distinguished by investigation of young (< 10 Myr) substellar objects. If brown dwarfs are small failed stars, we expect to find very low mass analogs of the Classical T Tauris, with primordial magnetic fields from the molecular cloud collapse. Accretion onto these objects leads to characteristic magnetic activity signatures such as chromospheric and coronal emission resulting in an ultraviolet excess continuum. The Orion OB1b association (m-M = 7.9, 2 Myr) provides a laboratory for following the strength and occurrence of the accretion process as a function of mass. Studies of the substellar mass function within the sigma Orionis cluster at the southern end of the association indicate that brown dwarfs are common. Based on model isochrones and the SDSS M dwarf sequence we expect the 95% completeness limit of the "Orion" scans to correspond to 0.1 and 0.03 solar masses for the u and g bands. Title: A First Look at White Dwarf-M Dwarf Pairs in the Sloan Digital Sky Survey Authors: Raymond, Sean N.; Szkody, Paula; Hawley, Suzanne L.; Anderson, Scott F.; Brinkmann, J.; Covey, Kevin R.; McGehee, P. M.; Schneider, D. P.; West, Andrew A.; York, D. G. Bibcode: 2003AJ....125.2621R Altcode: 2003astro.ph..2405R We have identified 109 white dwarf (WD)-M dwarf pairs in the Sloan Digital Sky Survey (SDSS) with g<20th magnitude. For each system we determined the temperature of the WD primary and the spectral type of the M dwarf secondary. Using Hα emission as a proxy for the chromospheric activity level of the M dwarf, we investigated correlations between the activity level and properties of the system. Compared with field M dwarfs previously observed in the Palomar/MSU Survey, we see a slightly higher active fraction of early-type stars, with activity levels similar to the field. We have conducted follow-up observations at the ARC 3.5 m telescope to obtain radial velocity information and to search for short-period binaries that may be on the verge of interacting. We report on one system with a 4.1 hr period and several additional systems with significant velocity variations. Title: Transition Region Emission from Very Low Mass Stars Authors: Hawley, Suzanne L.; Johns-Krull, Christopher M. Bibcode: 2003ApJ...588L.109H Altcode: 2003astro.ph..4542H We present results from our Cycle 10 Hubble Space Telescope (HST) program to search for transition region emission in very low mass main-sequence stars in the spectral range M7-M9. Our program is aimed at (1) detecting emission and (2) distinguishing between flaring and quiescent origin for the emission. We have obtained HST/Space Telescope Imaging Spectrograph time series observations of three active, very low mass stars (VB 8, VB 10, and LHS 2065), which show persistent activity in transition region lines including Si IV, C IV, and He II. Emission in transition region lines appears to be variable between exposures but is always observed. A strong flare was also observed in one 10 minute exposure on VB 10. Our results indicate that active, very low mass stars maintain a persistent quiescent chromosphere and transition region that is similar to those observed in active earlier type M dwarfs, in contrast to suggestions that these low-mass main-sequence stars exhibit only relatively strong flares and no quiescent emission. Title: Discovery of a New Nearby Star Authors: Teegarden, B. J.; Pravdo, S. H.; Hicks, M.; Lawrence, K.; Shaklan, S. B.; Covey, K.; Fraser, O.; Hawley, S. L.; McGlynn, T.; Reid, I. N. Bibcode: 2003ApJ...589L..51T Altcode: 2003astro.ph..2206T We report the discovery of a nearby star with a very large proper motion of 5.05"+/-0.03" yr-1. The star is called SO 025300.5+165258 and referred to herein as a high proper motion star (HPMS). The discovery came as a result of a search of the SkyMorph database, a sensitive and persistent survey that is well suited for finding stars with high proper motions. There are currently only seven known stars with proper motions greater than 5" yr-1. The spectrum and measured tangential velocity indicate that the HPMS is a main-sequence star with spectral type M6.5. Trigonometric and photometric parallaxes have been determined, yielding distance estimates of 2.4+0.7-0.4 pc (lower limit) and 3.6+/-0.4 pc, respectively. If the former is correct, the HPMS ranks third in the list of nearest stellar systems. If the latter is correct, it is 17th. A more precise trigonometric parallax measurement is expected to be completed near the end of the year. Title: Two Rare Magnetic Cataclysmic Variables with Extreme Cyclotron Features Identified in the Sloan Digital Sky Survey Authors: Szkody, Paula; Anderson, Scott F.; Schmidt, Gary; Hall, Patrick B.; Margon, Bruce; Miceli, Antonino; SubbaRao, Mark; Frith, James; Harris, Hugh; Hawley, Suzanne; Lawton, Brandon; Covarrubias, Ricardo; Covey, Kevin; Fan, Xiaohui; Murphy, Thomas; Narayanan, Vijay; Raymond, Sean; Rest, Armin; Strauss, Michael A.; Stubbs, Christopher; Turner, Edwin; Voges, Wolfgang; Bauer, Amanda; Brinkmann, J.; Knapp, Gillian R.; Schneider, Donald P. Bibcode: 2003ApJ...583..902S Altcode: 2002astro.ph..8241S Two newly identified magnetic cataclysmic variables discovered in the Sloan Digital Sky Survey (SDSS), SDSS J155331.12+551614.5 and SDSS J132411.57+032050.5, have spectra showing highly prominent, narrow, strongly polarized cyclotron humps with amplitudes that vary on orbital periods of 4.39 and 2.6 hr, respectively. In the former, the spacing of the humps indicates the third and fourth harmonics in a magnetic field of ~60 MG. The narrowness of the cyclotron features and the lack of strong emission lines imply very low temperature plasmas and very low accretion rates, so that the accreting area is heated by particle collisions rather than accretion shocks. The detection of rare systems like these exemplifies the ability of the SDSS to find the lowest accretion rate close binaries.

Based in part on observations obtained with the Sloan Digital Sky Survey (SDSS) and with the Apache Point Observatory (APO) 3.5 m telescope, which are owned and operated by the Astrophysical Research Consortium (ARC). A portion of the observations reported here were obtained at the MMT Observatory, a joint facility of the University of Arizona and the Smithsonian Institution. Title: White Dwarfs in Cataclysmic Variables: HST Results on GW LIB and Gleanings from SDSS Provide Insight on the Effects of Accretion Authors: Szkody, P.; Gänsicke, B. T.; Sion, E. M.; Howell, S. B.; Raymond, S.; Hawley, S. L. Bibcode: 2003ASIB..105..309S Altcode: 2003whsw.conf..309S; 2003whdw.conf..309S Cataclysmic variables (CVs) provide a rich laboratory to study the effects of mass transfer and accretion on the properties and evolution of white dwarfs. One interesting aspect is the effect of accretion on the instability strip. So far, there is only one ZZ Cet pulsator known to be a CV - GW Lib. Our UV spectra obtained with HST provide interesting results. The UV light curve of GW Lib reveals large amplitude pulsations at 3 periods while the spectrum shows a temperature hotter than single DAVs. However, our UV data on systems with WD temperatures in the DAV zone show no pulsation. The emerging SDSS database provides a rich resource for studies of many other aspects of accretion. So far, there are more than 60 new CVs and more than 100 WD+M pairs that have been found. A few of the unusual systems and some of the results on the pairs are highlighted.

The SDSS Web site is SDSS. Title: The Nature of High Velocity White Dwarfs Authors: Silvestri, Nicole M.; Oswalt, Terry D.; Hawley, Suzanne L. Bibcode: 2003ASIB..105..395S Altcode: 2003whsw.conf..395S; 2003whdw.conf..395S No abstract at ADS Title: The Quiescent and Flaring Atmosphere of the dMe Flare Star EV Lacertae Authors: Osten, R. A.; Hawley, S. L.; Johns-Krull, C. M.; Brown, A.; Ayres, T. R.; Ambruster, C. Bibcode: 2002AAS...201.1207O Altcode: 2002BAAS...34.1113O We report on a multi-wavelength campaign to observe flares on the dM4.5e flare star, EV Lac, in 2001 September. The campaign utilized the Chandra ACIS-HETGS, HST-STIS, VLA, and optical photometry and spectroscopy with the McDonald Observatory's 2.1 and 2.7m telescopes. The goal of the campaign was to characterize EV Lac's dynamic outer atmosphere and study the characteristics of magnetic energy release processes in a completely convective star. X-ray grating observations confirm the quiescent underabundance of iron deduced from previous low spectral resolution observations and show evidence of enhanced and variable Ne/Fe abundance ratios. Numerous flares were observed in the 100 ksec X-ray pointing; UV observations overlap one impulsive event, while radio and optical observations reveal impulsive flare signatures during a moderate X-ray flare. Preliminary results from a time-resolved spectroscopic analysis of the X-ray data will be presented, including determination of changing abundances, density, and temperature structure of the coronal plasma in EV Lac. The timing of flares in radio, UV, and optical will be compared against X-ray variations. A discussion of the observed multi-wavelength temporal trends will be given, and comparison made to solar flares. RAO acknowledges support from Chandra grant G01-2014A and HST grant GO-08880.04-A, as well as support from NRAO through a Jansky fellowship. Title: White Dwarf - M Dwarf Pairs in the Sloan Digital Sky Survey Authors: Bochanski, J.; Raymond, S.; Hawley, S.; Szkody, P.; Sloan Digtial Sky Survey Collaboration Bibcode: 2002AAS...201.1606B Altcode: 2002BAAS...34.1125B We present intial analysis of 109 White Dwarf (WD) - M dwarf pairs observed with the Sloan Digital Sky Survey (SDSS). For each of these pairs, the temperature of the WD primary and spectral type of the M dwarf were determined. Further examination of the M dwarfs was conducted, using Hα emission as a marker of chromospheric activity. Comparing this new data set to that of Hawley et al. (1996), we observe a somewhat higher active fraction of early-type M dwarfs in these pairs. Followup radial velocity observations at the ARC 3.5m telescope are being used to confirm any short period binaries with substantial velocity variations. These observations, which already span over 5 nights, have already detected a short period binary (P=4.1 hr). We have also produced a catalog of the WD - M dwarf pairs in the DR1 of the SDSS. We report on the status of this project. We gratefully acknoledge the support of NSF grant AST-0205875. Title: T Tauri and Chromospherically Active Stars in the SDSS II: Variability Authors: McGehee, P. M.; Ivezić, Ž.; Hawley, S. L. Bibcode: 2002AAS...201.1605M Altcode: 2002BAAS...34.1125M The detection of pre-main sequence and magnetically active low mass stars in the field via ultraviolet excess is complicated by the presence of white dwarf - M dwarf pairs (WD+M) in which the white dwarf signature mimics the excess continuum due to accretion or chromospheric activity. However, the use of synoptic survey data permits a clean separation between the WD+M and candidate T Tauris and dMe on the grounds of near-UV and blue variability. We utilize multi-epoch photometry obtained by the Sloan Digital Sky Survey to identify possible PMS and magnetically active M stars using changes in the SDSS u* and g* magnitudes. The spatial location of the resulting candidates are studied in relation to that of high-latitude molecular clouds. Title: Transition Region Emission From Very Low Mass Stars Authors: Johns-Krull, C. M.; Hawley, S. L. Bibcode: 2002AAS...201.1208J Altcode: 2002BAAS...34.1113J We present results from our cycle 10 HST program to search for transition region emission in very low mass stars in the spectral range M7-M9. Our program is aimed at 1) detecting emission; and 2) distinguishing between flaring and persistent origin for the emission. We have obtained time series observations of HST/STIS spectra of three active, very low mass stars (VB8, VB10, and LHS 2065) which reveal persistent emission in transition region lines including Si IV, C IV, and He II. This emission does show variability from one exposure to the next, but is always observed. A strong flare was also observed in one 10 minute exposure on VB10. Our preliminary analysis indicates that active, very low mass stars maintain a chromosphere and transition region that is similar to those observed in active, earlier type M dwarfs, in contrast to suggestions that these low mass stars exhibit only flaring activity. This research was made possible by grant HST-GO-9090 from the Space Telescope Science Institute, operated by AURA for NASA. Title: Multiwavelength Observations of Flares on AD Leo Authors: Allred, J. C.; Hawley, S. L.; Johns-Krull, C. M.; Fisher, G. H. Bibcode: 2002AAS...201.1205A Altcode: 2002BAAS...34R1113A In March 2000, a campaign was conducted to observe flares on the dM3e flare star AD Leo over a large range of wavelengths, using both ground and space-based observatories. Eight sizable flares and numerous smaller ones were observed over the four day duration of the campaign. We compare and contrast the behavior of the optical and ultraviolet continuum and emission lines during the large flares. We also investigate line broadening, velocity evolution and evidence for the Neupert effect. Title: Magnetic Activity in Low Mass Stars: SDSS Results Authors: Hawley, S. L.; West, A. A.; Covey, K. R.; Raymond, S. N.; Walkowicz, L. M. Bibcode: 2002AAS...201.1604H Altcode: 2002BAAS...34.1125H We present a study of the magnetic activity properties of low-mass stars in the Sloan Digital Sky Survey. Using the Hα emission line as an activity indicator, we examine the fraction of active stars as a function of spectral type and find a peak near type M7, confirming previous results. We investigate the ratio of the luminosity emitted in Hα compared to the bolometric luminosity for each star, and find a roughly constant ratio (with large scatter) over the range M0-M9. There does not appear to be a decrease in the ratio for types M8-M9, in contrast to previous determinations. We also explore the effect of metallicity on activity, and examine whether activity is correlated with changes in the SDSS colors. Title: The Space Density of Field Methane (``T") Dwarfs Authors: Collinge, M. J.; Knapp, G. R.; Fan, X.; Lupton, R. H.; Narayanan, V.; Strauss, M. A.; Gunn, J. E.; Schlegel, D. J.; Ivezić, Ž.; Rockosi, C. M.; Geballe, T. R.; Leggett, S. K.; Golimowski, D.; Hawley, S. L. Bibcode: 2002AAS...201.1603C Altcode: 2002BAAS...34.1125C We describe a complete magnitude-limited sample of 11 field methane (T) dwarfs brighter than z ≈ 20.2 selected from the imaging data of the Sloan Digital Sky Survey (SDSS). We discuss the optical and near-infrared colors of these and other extremely red objects and show that T dwarfs occupy a unique region in optical color-color space. The area density of methane dwarfs in this sample is one per 140 square degrees, and the space density is about one per 160 pc3. We use simulations to show that this is consistent with an IMF that is slowly rising toward lower mass through the substellar regime (dn/dm m-α , where α < 1), in reasonable agreement with the results of many open cluster studies. The inferred mass density in substellar objects is about 10% of that in stars. Funding for the SDSS is provided by the Alfred P. Sloan Foundation, NASA, NSF, DoE, Monbukagakusho, the Max Planck Society and the member institutions. The SDSS web site is http://www.sdss.org/. Title: Well Defined Areas of Doubt and Uncertainty in M Dwarf Astrophysics Authors: Hawley, S. L. Bibcode: 2002AAS...201.0201H Altcode: 2002AAS...201..201H; 2002BAAS...34.1094H Although M dwarfs comprise some 80% of the stars in the Galaxy, many of their properties remain unexplained. I will concentrate on three well-defined, unsolved problems in these stars, to wit: 1) the response of the M dwarf atmosphere to flare heating, a classic problem in stellar atmospheric physics; 2) the appearance of a break in the HR diagram in the mid-M dwarfs; and 3) the changes in surface magnetic activity through the M dwarf temperature sequence. I will show conclusively that, while our understanding of this ubiquitous population is far from complete, M dwarfs are an excellent testbed for stellar astrophysics. Title: The Sloan Digital Sky Survey low mass star & brown dwarf sample Authors: Covey, K. R.; Hawley, S. L.; Walkowicz, L. M.; SDSS Collaboration Bibcode: 2002AAS...201.1601C Altcode: 2002BAAS...34R1124C The large numbers of late type stars and brown dwarf candidates identified in the Sloan Digital Sky Survey's photometric and spectrscopic databases have laid the foundation for a study of the stellar population in the solar neighborhood, as well as at different heights within the Galactic disk. We characterize the photometric properties of these objects as a function of spectral type and present derived spectroscopic and photometric parallax relations. We describe the status of efforts to identify new candidates within the newly public Data Release 1, and discuss topics of stellar astrophysics and galactic structure for which this sample could hold promise. Title: VizieR Online Data Catalog: Radial velocities of high-velocity white dwarfs (Silvestri+, 2002) Authors: Silvestri, N. M.; Oswalt, T. D.; Hawley, S. L. Bibcode: 2002yCat..51241118S Altcode: Radial velocities and complete space motions were measured for 116 white dwarf stars with M dwarf companions (WD+M), including thirteen pairs having "halo-like" velocities. These 116 WD+dM binaries were observed on the 3.5 m telescope at the Apache Point Observatory (APO) on nearly 30 half-nights between 2000 September 4 and 2001 October 20. The APO Double Imaging Spectrograph was used with a 15" slit, yielding a resolution of approximately 2arcsrc/pixel.

>From the near-solar abundance levels of the M dwarf companions, only one potential stellar halo white dwarf (LP 164-52) was found in the sample, 12 of the 13 high-velocity white dwarfs being actually part of the high-velocity tail of the thick disk rather than the dark matter halo of the Galaxy.

(1 data file). Title: The Palomar/MSU Nearby Star Spectroscopic Survey. IV. The Luminosity Function in the Solar Neighborhood and M Dwarf Kinematics Authors: Reid, I. Neill; Gizis, John E.; Hawley, Suzanne L. Bibcode: 2002AJ....124.2721R Altcode: We have used new astrometric and spectroscopic observations to refine the volume-complete sample of M dwarfs defined in previous papers in this series. With the addition of Hipparcos astrometry, our revised VC2 sample includes 558 main-sequence stars in 448 systems. Analysis of that data set shows no evidence of any systematic kinematic bias. Combining those data with a Hipparcos-based sample of AFGK dwarfs within 25 pc of the Sun, we have derived the solar neighborhood luminosity function, Φ(MV), for stars with absolute magnitudes between -1 and +17. Using empirical and semiempirical mass-MV relations, we transform Φ(MV) to the present-day mass function, ψ(M) (=dN/dM). Depending on the mass-luminosity calibration adopted, ψ(M) can be represented by either a two-component or a three-component power law. In either case, the power-law index α has a value of ~1.3 at low masses (0.1 Msolar<M<0.7 Msolar), and the local mass density of main-sequence stars is ~0.031 Msolar pc-3. We have converted ψ(M) to an estimate of the initial mass function, Ψ(M), by allowing for stellar evolution, the density law perpendicular to the plane, and the local mix of stellar populations. The results give α=1.1-1.3 at low masses and α=2.5-2.8 at high masses, with the change in slope lying between 0.7 and 1.1 Msolar. Finally, the (U,W) velocity distributions of both the VC2 sample and the fainter (MV>4) stars in the Hipparcos 25 pc sample are well represented by two-component Gaussian distributions, with ~10% of the stars in the higher velocity dispersion component. We suggest that the latter component is the thick disk, and we offer a possible explanation for the relatively low velocity dispersions shown by ultracool dwarfs.

Based partly on observations made at the 60 inch (1.5 m) telescope at Palomar Mountain, which is jointly owned by the California Institute of Technology and the Carnegie Institution of Washington. Title: Wide Binary Systems and the Nature of High-Velocity White Dwarfs Authors: Silvestri, Nicole M.; Oswalt, Terry D.; Hawley, Suzanne L. Bibcode: 2002AJ....124.1118S Altcode: We present measured radial velocities and complete space motions for 116 white dwarf stars with M dwarf companions. Thirteen pairs have ``halo-like'' velocities. According to a recent study by Oppenheimer et al., all these high-velocity white dwarfs should be considered part of the dark matter heavy halo of the Galaxy, based on their kinematics. Based on the near-solar abundance levels of the M dwarf companions, we conclude that 12 of our 13 high-velocity white dwarfs are actually part of the high-velocity tail of the thick disk, rather than the dark matter halo of the Galaxy, in agreement with the results of a recent study of 514 M dwarfs performed by Reid, Sahu, & Hawley. We find only one potential stellar halo white dwarf (LP 164-52) in our sample. The M dwarf companion of LP 164-52 is a metal-poor, intermediate subdwarf with high-velocity UVW-space motions. In view of the similarity to our sample, we conclude that the majority of the dark matter halo white dwarfs identified by Oppenheimer et al. are most likely to be members of the thick disk, and hence their contribution to the dark matter content of the halo is very much overestimated. Our results suggest that the assignment of population membership solely on incomplete kinematical information is not definitive and that a more robust examination of suspected halo white dwarfs must be performed. Based on observations obtained with the Apache Point Observatory 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium, and the SARA Observatory at Kitt Peak, which is owned and operated by the Southeastern Association for Research in Astronomy. Title: The MACHO Project Large Magellanic Cloud Variable Star Inventory. XII. Three Cepheid Variables in Eclipsing Binaries Authors: Alcock, C.; Allsman, R. A.; Alves, D. R.; Becker, A. C.; Bennett, D. P.; Cook, K. H.; Drake, A. J.; Freeman, K. C.; Griest, K.; Hawley, S. L.; Keller, S.; Lehner, M. J.; Lepischak, D.; Marshall, S. L.; Minniti, D.; Nelson, C. A.; Peterson, B. A.; Popowski, P.; Pratt, M. R.; Quinn, P. J.; Rodgers, A. W.; Suntzeff, N.; Sutherland, W.; Vandehei, T.; Welch, D. L. Bibcode: 2002ApJ...573..338A Altcode: 2002astro.ph..1481A We present a method for solving the light curve of an eclipsing binary system that contains a Cepheid variable as one of its components as well as the solutions for three eclipsing Cepheids in the Large Magellanic Cloud (LMC). A geometric model is constructed in which the component stars are assumed to be spherical and on circular orbits. The emergent system flux is computed as a function of time, with the intrinsic variations in temperature and radius of the Cepheid treated self-consistently. Fitting the adopted model to photometric observations, incorporating data from multiple bandpasses, yields a single parameter set best describing the system. This method is applied to three eclipsing Cepheid systems from the MACHO project LMC database: MACHO 6.6454.5, 78.6338.24, and 81.8997.87. A best-fit value is obtained for each system's orbital period and inclination and for the relative radius, color, and limb-darkening coefficients of each star. Pulsation periods and parameterizations of the intrinsic color variations of the Cepheids are also obtained, and the amplitude of the radial pulsation of each Cepheid is measured directly. The system 6.6454.5 is found to contain a 4.97 day Cepheid, which cannot be definitely classified as type I or type II, with an unexpectedly brighter companion. The system 78.6338.24 consists of a 17.7 day, W Virginis class type II Cepheid with a smaller, dimmer companion. The system 81.8997.87 contains an intermediate-mass, 2.03 day overtone Cepheid with a dimmer, red giant secondary. Title: The Palomar/MSU Nearby Star Spectroscopic Survey. III. Chromospheric Activity, M Dwarf Ages, and the Local Star Formation History Authors: Gizis, John E.; Reid, I. Neill; Hawley, Suzanne L. Bibcode: 2002AJ....123.3356G Altcode: 2002astro.ph..3499G We present high-resolution echelle spectroscopy of 676 nearby M dwarfs. Our measurements include radial velocities, equivalent widths of important chromospheric emission lines, and rotational velocities for rapidly rotating stars. We identify several distinct groups by their Hα properties and investigate variations in chromospheric activity among early (M0-M2.5) and mid (M3-M6) dwarfs. Using a volume-limited sample together with a relationship between age and chromospheric activity, we show that the rate of star formation in the immediate solar neighborhood has been relatively constant over the last 4 Gyr. In particular, our results are inconsistent with recent large bursts of star formation. We use the correlation between Hα activity and age as a function of color to set constraints on the properties of L and T dwarf secondary components in binary systems. We also identify a number of interesting stars, including rapid rotators, radial velocity variables, and spectroscopic binaries. Observations were made at the 60 inch telescope at Palomar Mountain, which is jointly owned by the California Institute of Technology and the Carnegie Institution of Washington. Title: Characterization of M, L, and T Dwarfs in the Sloan Digital Sky Survey Authors: Hawley, Suzanne L.; Covey, Kevin R.; Knapp, Gillian R.; Golimowski, David A.; Fan, Xiaohui; Anderson, Scott F.; Gunn, James E.; Harris, Hugh C.; Ivezić, Željko; Long, Gary M.; Lupton, Robert H.; McGehee, Peregrine M.; Narayanan, Vijay; Peng, Eric; Schlegel, David; Schneider, Donald P.; Spahn, Emily Y.; Strauss, Michael A.; Szkody, Paula; Tsvetanov, Zlatan; Walkowicz, Lucianne M.; Brinkmann, J.; Harvanek, Michael; Hennessy, Gregory S.; Kleinman, S. J.; Krzesinski, Jurek; Long, Dan; Neilsen, Eric H.; Newman, Peter R.; Nitta, Atsuko; Snedden, Stephanie A.; York, Donald G. Bibcode: 2002AJ....123.3409H Altcode: 2002astro.ph..4065H An extensive sample of M, L, and T dwarfs identified in the Sloan Digital Sky Survey (SDSS) has been compiled. The sample of 718 dwarfs includes 677 new objects (629 M dwarfs and 48 L dwarfs), together with 41 that have been previously published. All new objects and some of the previously published ones have new optical spectra obtained either with the SDSS spectrographs or with the Apache Point Observatory 3.5 m ARC telescope. Spectral types and SDSS colors are available for all objects; approximately 35% also have near-infrared magnitudes measured by 2MASS (Two Micron All Sky Survey) or on the Mauna Kea system. We use this sample to characterize the color-spectral type and color-color relations of late-type dwarfs in the SDSS filters and to derive spectroscopic and photometric parallax relations for use in future studies of the luminosity and mass functions based on SDSS data. We find that the i*-z* and i*-J colors provide good spectral type and absolute magnitude (Mi*) estimates for M and L dwarfs. Our distance estimates for the current sample indicate that SDSS is finding early M dwarfs out to ~1.5 kpc, L dwarfs to ~100 pc, and T dwarfs to ~20 pc. The T dwarf photometric data show large scatter and are therefore less reliable for spectral type and distance estimation. Based on observations obtained with the Sloan Digital Sky Survey and the Apache Point Observatory 3.5 m telescope, which are owned and operated by the Astrophysical Research Consortium. Title: Multiwavelength Flares on AD Leo Authors: Allred, J. C.; Hawley, S. L.; Johns-Krull, C. M.; Fisher, G. H. Bibcode: 2002AAS...200.7408A Altcode: 2002BAAS...34..771A We report on a multiwavelength flare campaign conducted during March, 2000 on the dM3e flare star AD Leo. Participating observatories included HST, EUVE, McDonald, DAO, Stephanion, CrAO, and Jodrell Bank. We present a preliminary analysis of the optical and ultraviolet photometry and spectrosocpy obtained during several flares observed with multiple instruments. The CIV light curves and velocity evolution are consistent with models of chromospheric evaporation and condensation which are commonly applied to solar flares. Title: Transition Region Emission Observed During a Flare on VB8 Authors: Hawley, S. L.; Johns-Krull, C. M. Bibcode: 2002AAS...200.7416H Altcode: 2002BAAS...34..772H We present results from our cycle 10 HST program to search for transition region emission in very low mass stars. Our program is aimed at 1) detecting emission; and 2) distinguishing between flaring and persistent origin for the emission. Observations of our first target, VB8 (dM7e), comprise a sequence of 15 exposures with STIS, each of 5 minute duration. Our preliminary analysis indicates that we detect C IV and He I emission during only one of the exposures. This supports the hypothesis that transition region emission occurs as the result of transient flare activity in very low mass stars. This research was made possible by grant HST-GO-9090 from the Space Telescope Science Institute, operated by AURA for NASA. Title: Is There an Empirical Connection Between Rotation and Activity in Low Mass Stars? Authors: Hawley, Suzanne Bibcode: 2002smra.progE...9H Altcode: No abstract at ADS Title: Sloan Digital Sky Survey: Early Data Release Authors: Stoughton, Chris; Lupton, Robert H.; Bernardi, Mariangela; Blanton, Michael R.; Burles, Scott; Castander, Francisco J.; Connolly, A. J.; Eisenstein, Daniel J.; Frieman, Joshua A.; Hennessy, G. S.; Hindsley, Robert B.; Ivezić, Željko; Kent, Stephen; Kunszt, Peter Z.; Lee, Brian C.; Meiksin, Avery; Munn, Jeffrey A.; Newberg, Heidi Jo; Nichol, R. C.; Nicinski, Tom; Pier, Jeffrey R.; Richards, Gordon T.; Richmond, Michael W.; Schlegel, David J.; Smith, J. Allyn; Strauss, Michael A.; SubbaRao, Mark; Szalay, Alexander S.; Thakar, Aniruddha R.; Tucker, Douglas L.; Vanden Berk, Daniel E.; Yanny, Brian; Adelman, Jennifer K.; Anderson, John E., Jr.; Anderson, Scott F.; Annis, James; Bahcall, Neta A.; Bakken, J. A.; Bartelmann, Matthias; Bastian, Steven; Bauer, Amanda; Berman, Eileen; Böhringer, Hans; Boroski, William N.; Bracker, Steve; Briegel, Charlie; Briggs, John W.; Brinkmann, J.; Brunner, Robert; Carey, Larry; Carr, Michael A.; Chen, Bing; Christian, Damian; Colestock, Patrick L.; Crocker, J. H.; Csabai, István; Czarapata, Paul C.; Dalcanton, Julianne; Davidsen, Arthur F.; Davis, John Eric; Dehnen, Walter; Dodelson, Scott; Doi, Mamoru; Dombeck, Tom; Donahue, Megan; Ellman, Nancy; Elms, Brian R.; Evans, Michael L.; Eyer, Laurent; Fan, Xiaohui; Federwitz, Glenn R.; Friedman, Scott; Fukugita, Masataka; Gal, Roy; Gillespie, Bruce; Glazebrook, Karl; Gray, Jim; Grebel, Eva K.; Greenawalt, Bruce; Greene, Gretchen; Gunn, James E.; de Haas, Ernst; Haiman, Zoltán; Haldeman, Merle; Hall, Patrick B.; Hamabe, Masaru; Hansen, Brad; Harris, Frederick H.; Harris, Hugh; Harvanek, Michael; Hawley, Suzanne L.; Hayes, J. J. E.; Heckman, Timothy M.; Helmi, Amina; Henden, Arne; Hogan, Craig J.; Hogg, David W.; Holmgren, Donald J.; Holtzman, Jon; Huang, Chih-Hao; Hull, Charles; Ichikawa, Shin-Ichi; Ichikawa, Takashi; Johnston, David E.; Kauffmann, Guinevere; Kim, Rita S. J.; Kimball, Tim; Kinney, E.; Klaene, Mark; Kleinman, S. J.; Klypin, Anatoly; Knapp, G. R.; Korienek, John; Krolik, Julian; Kron, Richard G.; Krzesiński, Jurek; Lamb, D. Q.; Leger, R. French; Limmongkol, Siriluk; Lindenmeyer, Carl; Long, Daniel C.; Loomis, Craig; Loveday, Jon; MacKinnon, Bryan; Mannery, Edward J.; Mantsch, P. M.; Margon, Bruce; McGehee, Peregrine; McKay, Timothy A.; McLean, Brian; Menou, Kristen; Merelli, Aronne; Mo, H. J.; Monet, David G.; Nakamura, Osamu; Narayanan, Vijay K.; Nash, Thomas; Neilsen, Eric H., Jr.; Newman, Peter R.; Nitta, Atsuko; Odenkirchen, Michael; Okada, Norio; Okamura, Sadanori; Ostriker, Jeremiah P.; Owen, Russell; Pauls, A. George; Peoples, John; Peterson, R. S.; Petravick, Donald; Pope, Adrian; Pordes, Ruth; Postman, Marc; Prosapio, Angela; Quinn, Thomas R.; Rechenmacher, Ron; Rivetta, Claudio H.; Rix, Hans-Walter; Rockosi, Constance M.; Rosner, Robert; Ruthmansdorfer, Kurt; Sandford, Dale; Schneider, Donald P.; Scranton, Ryan; Sekiguchi, Maki; Sergey, Gary; Sheth, Ravi; Shimasaku, Kazuhiro; Smee, Stephen; Snedden, Stephanie A.; Stebbins, Albert; Stubbs, Christopher; Szapudi, István; Szkody, Paula; Szokoly, Gyula P.; Tabachnik, Serge; Tsvetanov, Zlatan; Uomoto, Alan; Vogeley, Michael S.; Voges, Wolfgang; Waddell, Patrick; Walterbos, René; Wang, Shu-i.; Watanabe, Masaru; Weinberg, David H.; White, Richard L.; White, Simon D. M.; Wilhite, Brian; Wolfe, David; Yasuda, Naoki; York, Donald G.; Zehavi, Idit; Zheng, Wei Bibcode: 2002AJ....123..485S Altcode: The Sloan Digital Sky Survey (SDSS) is an imaging and spectroscopic survey that will eventually cover approximately one-quarter of the celestial sphere and collect spectra of ~106 galaxies, 100,000 quasars, 30,000 stars, and 30,000 serendipity targets. In 2001 June, the SDSS released to the general astronomical community its early data release, roughly 462 deg2 of imaging data including almost 14 million detected objects and 54,008 follow-up spectra. The imaging data were collected in drift-scan mode in five bandpasses (u, g, r, i, and z); our 95% completeness limits for stars are 22.0, 22.2, 22.2, 21.3, and 20.5, respectively. The photometric calibration is reproducible to 5%, 3%, 3%, 3%, and 5%, respectively. The spectra are flux- and wavelength-calibrated, with 4096 pixels from 3800 to 9200 Å at R~1800. We present the means by which these data are distributed to the astronomical community, descriptions of the hardware used to obtain the data, the software used for processing the data, the measured quantities for each observed object, and an overview of the properties of this data set. Title: Toward Spectral Classification of L and T Dwarfs: Infrared and Optical Spectroscopy and Analysis Authors: Geballe, T. R.; Knapp, G. R.; Leggett, S. K.; Fan, X.; Golimowski, D. A.; Anderson, S.; Brinkmann, J.; Csabai, I.; Gunn, J. E.; Hawley, S. L.; Hennessy, G.; Henry, T. J.; Hill, G. J.; Hindsley, R. B.; Ivezić, Ž.; Lupton, R. H.; McDaniel, A.; Munn, J. A.; Narayanan, V. K.; Peng, E.; Pier, J. R.; Rockosi, C. M.; Schneider, D. P.; Smith, J. Allyn; Strauss, M. A.; Tsvetanov, Z. I.; Uomoto, A.; York, D. G.; Zheng, W. Bibcode: 2002ApJ...564..466G Altcode: 2001astro.ph..8443G We present 0.6-2.5 μm, R>~400 spectra of 27 cool, low-luminosity stars and substellar objects. Based on these and previously published spectra, we develop a preliminary spectral classification system for L and T dwarfs. For late L and T types the classification system is based entirely on four spectral indices in the 1-2.5 μm interval. Two of these indices are derived from water absorption bands at 1.15 and 1.4 μm, the latter of which shows a smooth increase in depth through the L and T sequences and can be used to classify both spectral types. The other two indices make use of methane absorption features in the H and K bands, with the K-band index also applicable to mid-to-late L dwarfs. Continuum indices shortward of 1 μm used by previous authors to classify L dwarfs are found to be useful only through mid-L subclasses. We employ the 1.5 μm water index and the 2.2 μm methane index to complete the L classification through L9.5 and to link the new system with a modified version of the 2MASS ``color-d'' index. By correlating the depths of the methane and water absorption features, we establish a T spectral sequence from T0 to T8, based on all four indices, that is a smooth continuation of the L sequence. We reclassify two 2MASS L8 dwarfs as L9 and L9.5 and identify one SDSS object as L9. In the proposed system methane absorption appears in the K band approximately at L8, two subclasses earlier than its appearance in the H band. The L and T spectral classes are distinguished by the absence and presence, respectively, of H-band methane absorption. Title: L Dwarfs Found in Sloan Digital Sky Survey Commissioning Data. II. Hobby-Eberly Telescope Observations Authors: Schneider, Donald P.; Knapp, Gillian R.; Hawley, Suzanne L.; Covey, Kevin R.; Fan, Xiaohui; Ramsey, Lawrence W.; Richards, Gordon T.; Strauss, Michael A.; Gunn, James E.; Hill, Gary J.; MacQueen, Phillip J.; Adams, Mark T.; Hill, Grant M.; Ivezić, Željko; Lupton, Robert H.; Pier, Jeffrey R.; Saxe, David H.; Shetrone, Matthew; Tufts, Joseph R.; Wolf, Marsha J.; Brinkmann, J.; Csabai, István; Hennessy, G. S.; York, Donald G. Bibcode: 2002AJ....123..458S Altcode: 2001astro.ph.10273S Low-dispersion optical spectra have been obtained with the Hobby-Eberly Telescope of 22 very red objects found in early imaging data from the Sloan Digital Sky Survey (SDSS). The objects are assigned spectral types on the Two Micron All Sky Survey (2MASS) system and are found to range from late M to late L. The red and near-infrared colors from SDSS and 2MASS correlate closely with each other, and most of the colors are closely related to spectral type in this range; the exception is the i*-z* color, which appears to be independent of spectral type between about M7 and L4. The spectra suggest that this independence is due to the disappearance of the TiO and VO absorption in the i band for later spectral types, the presence of strong Na I and K I absorption in the i band, and the gradual disappearance of the 8400 Å absorption of TiO and FeH in the z band. Based on observations obtained with the Sloan Digital Sky Survey, which is owned and operated by the Astrophysical Research Consortium, and on observations obtained with the Hobby-Eberly Telescope, which is a joint project of the University of Texas at Austin, Pennsylvania State University, Stanford University, Ludwig-Maximillians-Universität München, and Georg-August-Universität Göttingen. Title: EUVE and Multiwavelength Studies of Stellar Flares Authors: Hawley, S. L. Bibcode: 2002ASPC..264..123H Altcode: 2002ccea.conf..123H No abstract at ADS Title: Cataclysmic Variables from The Sloan Digital Sky Survey. I. The First Results Authors: Szkody, Paula; Anderson, Scott F.; Agüeros, Marcel; Covarrubias, Ricardo; Bentz, Misty; Hawley, Suzanne; Margon, Bruce; Voges, Wolfgang; Henden, Arne; Knapp, Gillian R.; Vanden Berk, Daniel E.; Rest, Armin; Miknaitis, Gajus; Magnier, Eugene; Brinkmann, J.; Csabai, I.; Harvanek, M.; Hindsley, R.; Hennessy, G.; Ivezic, Z.; Kleinman, S. J.; Lamb, D. Q.; Long, D.; Newman, P. R.; Neilsen, E. H.; Nichol, R. C.; Nitta, A.; Schneider, D. P.; Snedden, S. A.; York, D. G. Bibcode: 2002AJ....123..430S Altcode: 2001astro.ph.10291S The commissioning year of the Sloan Digital Sky Survey (SDSS) has demonstrated that many cataclysmic variables (CVs) have been missed in previous surveys with brighter limits. We report the identification of 22 CVs, of which 19 are new discoveries and three are known systems (SW UMa, BH Lyn, and OU Vir). A compendium of positions, colors, and characteristics of these systems obtained from the SDSS photometry and spectroscopy is presented, along with data obtained during follow-up studies with the Apache Point Observatory and Manastash Ridge Observatory telescopes. We have determined orbital periods for three of the new systems, two show dwarf nova outbursts, and the third is a likely magnetic system with eclipses of its region of line emission. Based on these results, we expect the completed survey to locate at least 400 new CVs. Most of these will be faint systems with low accretion rates that will provide new constraints on binary evolution models. Based on observations obtained with the Sloan Digital Sky Survey and with the Apache Point Observatory 3.5 m telescope, which are owned and operated by the Astrophysical Research Consortium. Title: Infrared Photometry of Late-M, L, and T Dwarfs Authors: Leggett, S. K.; Golimowski, David A.; Fan, Xiaohui; Geballe, T. R.; Knapp, G. R.; Brinkmann, J.; Csabai, István; Gunn, James E.; Hawley, Suzanne L.; Henry, Todd J.; Hindsley, Robert; Ivezić, Željko; Lupton, Robert H.; Pier, Jeffrey R.; Schneider, Donald P.; Smith, J. Allyn; Strauss, Michael A.; Uomoto, Alan; York, D. G. Bibcode: 2002ApJ...564..452L Altcode: 2001astro.ph..8435L We present ZJHKL'M' photometry of a sample of 58 late M, L, and T dwarfs, most of which are identified from the Sloan Digital Sky Survey and the Two Micron All-Sky Survey. Near-infrared spectra and spectral classifications for most of this sample are presented in a companion paper by Geballe et al. We derive the luminosities of 18 dwarfs in the sample with known parallaxes, and the results imply that the effective temperature range for the L dwarfs in our sample is approximately 2200-1300 K and for the T dwarfs 1300-800 K. We obtained new photometric data at the United Kingdom Infrared Telescope for: 42 dwarfs at Z, 34 dwarfs at JHK, 21 dwarfs at L', as well as M' data for two L dwarfs and two T dwarfs. The M' data provide the first accurate photometry for L and T dwarfs in this bandpass-for a T2 and a T5 dwarf, we find K-M'=1.2 and 1.6, respectively. These colors are much bluer than predicted by published models, suggesting that CO may be more abundant in these objects than expected, as has been found for the T6 dwarf Gl 229B. We also find that K-L' increases monotonically through most of the M, L, and T subclasses, but it is approximately constant between types L6 and T5, restricting its usefulness as a temperature indicator. The degeneracy is probably due to the onset of CH4 absorption at the blue edge of the L' bandpass. The JHK colors of L dwarfs show significant scatter, suggesting that the fluxes in these bandpasses are sensitive to variations in photospheric dust properties. The H-K colors of the later T dwarfs also show some scatter, which we suggest is due to variations in pressure-induced H2 opacity, which is sensitive to gravity and metallicity. Title: LONEOS RR Lyrae Survey: Early Results Authors: Miceli, A.; Rest, A.; Miknaitis, G. A.; Covarrubias, R.; Stubbs, C. W.; Hawley, S.; Magnier, G.; Koehn, B.; Bowell, T.; Cook, K. Bibcode: 2001AAS...19910111M Altcode: 2001BAAS...33.1463M We have investigated 6000 sq. deg. of data from the Lowell Observatory Near Earth Object Survey (LONEOS) with more than 20 epochs down to a limiting magnitude of 19 in R (see Rest, et.al these proceedings). From this dataset, thousands of candidate RR Lyrae stars have been extracted. RR Lyrae stars are excellent standard candles for two reasons: they have characteristic lightcurves which make them easily identifiable, and they also have small scatter in their intrinsic brightness. Thus, a sufficiently large sample of Galactic RR Lyrae stars can probe the structure of the Galaxy. We present lightcurves of several newly discovered RR Lyrae. We also present follow-up photometry with the 3.5-m Apache Point Observatory (APO) and 0.76-m Manastash Ridge Observatory (MRO) to determine the degree of contamination and for the refinement of selection criteria. Finally, we present radial velocity measurements taken at APO for a small sample of RR Lyrae stars identified in LONEOS. Title: T Tauri and Chromospherically Active Stars in the SDSS I: Photometric Selection and First Results Authors: McGehee, P. M.; Hawley, S. L.; Ivezic, Z. Bibcode: 2001AAS...199.8901M Altcode: 2001BAAS...33.1434M We present first results from the Sloan Digital Sky Survey T Tauri and flare star program including new Classical T Tauris and related emission line stars selected on the basis of SDSS u*g^*r^*i^*z^* photometry and spectroscopically verified using the facilities at Apache Point Observatory (APO) and Calar Alto Observatory (CAHA). The photometric search criteria make use of reddening invariant combinations of the SDSS passbands to select for late spectral type stars exhibiting an ultraviolet excess. The depth of the SDSS UV-excess technique is compared with other wide-field surveys including IRAS, RASS, and, in detail, 2MASS, where it is evident that the SDSS will excel in the detection of dMe and the post-circumstellar disk Weak-lined T Tauris that are expected to comprise the bulk of the high galactic latitude pre-main-sequence star population. Title: High-Velocity White Dwarfs: Thick Disk, Not Dark Matter Authors: Reid, I. Neill; Sahu, Kailash C.; Hawley, Suzanne L. Bibcode: 2001ApJ...559..942R Altcode: 2001astro.ph..4110R We present an alternative interpretation of the nature of the extremely cool, high-velocity white dwarfs identified by Oppenheimer et al. in a high-latitude astrometric survey. We argue that the velocities of the majority of the sample are more consistent with the high-velocity tail of a rotating population, probably the thick disk, rather than with a pressure-supported halo system. Indeed, the observed numbers are well matched by predictions based on the kinematics of a complete sample of nearby M dwarfs. Analyzing only stars showing retrograde motion gives a local density close to that expected for white dwarfs in the stellar (R-3.5) halo. Under our interpretation, none of the white dwarfs need be assigned to the dark matter heavy halo. However, luminosity functions derived from observations of these stars can set important constraints on the age of the oldest stars in the Galactic disk. Title: The Chromospheric Activity-Age Relation for M Dwarf Stars Authors: Silvestri, Nicole M.; Oswalt, Terry D.; Hawley, Suzanne L. Bibcode: 2001noao.prop..254S Altcode: We propose to complete our study of M dwarf/white dwarf binary systems with the goal of determining the correlation between the chromospheric activity and ages of M dwarf stars for ages up to the age of the galactic disk (~M7-8; ~10 Gyr). This project is unique in that it uses the well determined age of the white dwarf to establish the age of the M dwarf in the binary system. Previous studies used open clusters for age determination, and were confined to ages < 5 Gyr. These indicated the surprising result that the age at which activity ceased depended on the mass (temperature, color) of the M dwarf, in contrast to the well known Skumanich relation for early type F-G-K stars where the age-activity relation is a manifestation of the rotational velocity evolution. Such a different age-activity relation has important consequences for understanding the dynamo generation of the magnetic fields in the lowest mass stars and brown dwarfs, and the different manifestations of the magnetic activity compared to solar-type stars. Title: A Next Generation Microlensing Survey of the LMC Authors: Stubbs, Christopher W.; Cook, Kem; Hawley, Suzanne; Welch, Doug; Alcock, Charles; Mighell, Ken; Becker, Andrew; Nelson, Cailin; Drake, Andrew; Rest, Armin; Miknaitis, Gajus; Keller, Stefan Bibcode: 2001noao.prop...37S Altcode: One of the foremost outstanding problems in the physical sciences is the nature and distribution of the ``dark matter'' that is the gravitationally dominant component of mass in all galaxies, including the Milky Way. One way to search for astrophysical dark matter objects (often called MAssive Compact Halo Objects, or MACHOs) is to search for the transient brightening of background stars due to the gravitational lensing by foreground MACHOs. A previous experiment has produced a peculiar result: While the detected rate of gravitational lensing events indicates that MACHOs comprise at most perhaps 20% of the dark matter halo, the number of events far exceeds that expected from known stellar populations. The nature of these excess lensing objects remains a mystery. We intend to determine the nature of this lensing population, which may outweigh all other known components of the Galaxy, by conducting a search with at least a tenfold improvement in the event detection rate. This will be one of the deepest time-domain surveys to date. The survey will have no proprietary data period, and we can draw heavily upon existing tools to provide useful access to the data. Title: Transition Region Emission in Very Low Mass Stars Authors: Hawley, Suzanne Bibcode: 2001hst..prop.9090H Altcode: 2001hst..prop.5438H The origin of the magnetic heating which produces hot outer atmospheres in late-type stars is one of the most interesting, and elusive, problems in stellar astrophysics. Our poor understanding is due in part to the lack of data for a large and varied sample of stars, which are needed to provide the basis for a general theory. Observationally, our knowledge is particularly sparse for the very low mass stars. In fact, diametrically opposed conclusions have been reached in this field: the available data has been interpreted 1.} to indicate that magnetic heating of the hot transition region and corona becomes relatively more important in stars of later spectral type {lower mass} - the pre-1999 position; and 2.} to claim that the magnetic heating is insufficient to produce these regions at all, except during flares, in very low mass objects - the current widely held view. The manifestations of magnetic activity at the stellar/brown dwarf boundary have yet to be probed in transition region diagnostics; previous IUE and HST/GHRS observations were not sensitive enough to provide constraining data. Our proposed HST/STIS observations of three very low mass stars will conclusively show if quiescent magnetic heating sufficient to produce a hot outer atmosphere still exists in these objects, or whether they are categorically different than higher mass M dwarfs. Title: SDSS Stellar Spectroscopy Authors: Pier, J. R.; Harris, H. C.; Vanden Berk, D. E.; Bauer, A.; Anderson, S. F.; Hawley, S. L.; Margon, B.; Szkody, P.; Knapp, G. R.; Schlegel, D.; Strauss, M. A.; SDSS Collaboration Bibcode: 2000AAS...197.1310P Altcode: 2000BAAS...32.1424P While the SDSS spectroscopic survey is intended primarily to obtain redshifts of galaxies and quasars, spectra of thousands of stars are also being obtained. Some of these stars are intended spectroscopic targets: there are standards of various kinds, stars targeted for stellar science and/or Galactic structure science, and objects that are assigned spectroscopic fibers due to their unusual location in 5-color space. We present a number of spectra showing the spectral sequence of early through late stellar types. This sequence demonstrates the coverage, resolution, and spectral classification capabilities of the SDSS spectrographs and shows the promise of a stellar spectral atlas of SDSS spectra, currently under construction. We also show spectra of unusual objects. Many of these are of relatively rare, though previously classified, stellar types or binary systems. But some of the more unusual spectra show stellar features that have defied classification to date. Title: The Chromospheric Activity-Age Relation for M Dwarf Stars Authors: Silvestri, N. M.; Oswalt, T. D.; Hawley, S. L. Bibcode: 2000AAS...197.4416S Altcode: 2000BAAS...32.1474S We present preliminary results from our study in which we use moderate resolution spectroscopy to determine the correlation between the chromospheric activity and age of M dwarf stars in wide binary systems. We have observed ~50 M dwarf stars from our sample with the Apache Point Observatory 3.5-m telescope. We measure the ratio of Hα luminosity to the bolometric luminosity (LHα /Lbol) of the M dwarf---a measure of activity that is proven to correlate well with age. This project is unique in that it will extend the chromospheric activity-age relation of low-mass main sequence stars beyond the ages provided by cluster methods. The ages so determined are also independent of the uncertainties in cluster age determinations. The technique has the potential to improve by at least a factor of two the precision and the range over which ages can currently be determined for main sequence stars. Work on this project is supported by the NASA Graduate Student Researchers Program grant NGT-50290 (N.M.S.). Title: Optical Spectroscopy of Supernova 1993J During Its First 2500 Days Authors: Matheson, Thomas; Filippenko, Alexei V.; Barth, Aaron J.; Ho, Luis C.; Leonard, Douglas C.; Bershady, Matthew A.; Davis, Marc; Finley, David S.; Fisher, David; González, Rosa A.; Hawley, Suzanne L.; Koo, David C.; Li, Weidong; Lonsdale, Carol J.; Schlegel, David; Smith, Harding E.; Spinrad, Hyron; Wirth, Gregory D. Bibcode: 2000AJ....120.1487M Altcode: 2000astro.ph..6263M We present 42 low-resolution spectra of supernova (SN) 1993J, our complete collection from the Lick and Keck observatories, from day 3 after explosion to day 2454, as well as one Keck high-dispersion spectrum from day 383. SN 1993J began as an apparent SN II, albeit an unusual one. After a few weeks, a dramatic transition took place, as prominent helium lines emerged in the spectrum. SN 1993J had metamorphosed from a SN II to a SN IIb. Nebular spectra of SN 1993J closely resemble those of SNe Ib and Ic, but with a persistent Hα line. At very late times, the Hα emission line dominated the spectrum, but with an unusual, boxlike profile. This is interpreted as an indication of circumstellar interaction. Title: Coordinated Observations of Stellar Flares on AD Leo Authors: Hawley, Suzanne Bibcode: 2000hst..prop.8613H Altcode: 2000hst..prop.4949H We will obtain high resolution HST/STIS spectra of the dMe star AD Leo during periods of quiescence and during flares to study the physics of atmospheric heating in flare stars. The HST observations will form an essential part of a large, coordinated observing campaign including FUSE, EUVE, and ground-based observations {both multicolor photometry and high resolution optical spectroscopy}. The STIS spectra, in combination with data from the other satellites, will allow us to determine the structure {during quiescence} and evolution {during flares} of the temperature and density in the corona, transition region, and chromosphere. These data will provide strong empirical constraints on our current generation of flare evolution models. The uniquely high spectral resolution of the STIS data will also allow us to directly observe the dynamic effects of the chromospheric shocks that are predicted by the models. In addition, we will search for significant red-shifted emission in the hydrogen Lyman-Alpha line during the flare rise phase, which is a signature of an energetic proton beam. The existence and role of proton beams in both solar and stellar flares is currently a subject of considerable debate. Title: CCD photometry and proper motions of late-type stars in the young open cluster Stock 2 Authors: Foster, D. C.; Theissen, A.; Butler, C. J.; Rolleston, W. R. J.; Byrne, P. B.; Hawley, S. L. Bibcode: 2000A&AS..143..409F Altcode: We present the results of the first CCD BVRI photometric and proper motion study of late-type stars in the young open cluster Stock 2. Twenty-one fields of approximately 5'x 5' size have been observed photometrically, from which we have identified 118 candidate members based on their positions on colour-magnitude diagrams relative to theoretical isochrones. From a comparison of the known star density of the Pleiades, we estimate the contamination of this selection process due to background stars to be as large as ~ 50%. However, only 22 of those 118 candidate members have proper motions consistent with membership, suggesting that the contamination is of the order of 80%. Additional candidate members were found by means of a proper motion analysis of Schmidt plate material for a 3degx 3deg field containing the cluster. The cluster proper motion allows us to separate members from background and foreground stars. We have found 634 stars with a membership probability >= 50% down to a limiting magnitude of B ~ 20, corresponding to late-M dwarfs at the distance of Stock 2. Table 5 and the Table Appendix are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html. Title: VizieR Online Data Catalog: Stock 2 CCD photometry and proper motions (Foster+, 2000) Authors: Foster, D. C.; Theissen, A.; Butler, C. J.; Rolleston, W. R. J.; Byrne, P. B.; Hawley, S. L. Bibcode: 2000yCat..41430409F Altcode: We present the results of the first CCD BVRI photometric and proper motion study of late-type stars in the young open cluster Stock 2. Twenty-one fields of approximately 5'x5' size have been observed photometrically, from which we have identified 118 candidate members based on their positions on colour-magnitude diagrams relative to theoretical isochrones. From a comparison of the known star density of the Pleiades, we estimate the contamination of this selection process due to background stars to be as large as ~50%. However, only 22 of those 118 candidate members have proper motions consistent with membership, suggesting that the contamination is of the order of 80%. Additional candidate members were found by means of a proper motion analysis of Schmidt plate material for a 3°x3° field containing the cluster. The cluster proper motion allows us to separate members from background and foreground stars. We have found 634 stars with a membership probability >=50% down to a limiting magnitude of B=~20, corresponding to late-M dwarfs at the distance of Stock 2. (2 data files). Title: Understanding The Secondary in AL Com Authors: Szkody, Paula; Hawley, Suzanne; Harrison, Thomas; Howell, Steve; Laws, Chris Bibcode: 2000noao.prop..362S Altcode: We will use the MMT Spectrograph at moderate resolution to explore the secondary in the faint (20th mag), ultrashort period (81 min) cataclysmic variable AL Com. WHT optical spectra obtained during our HST UV spectral program in 1996 indicated broad band features consistent with MgH and CaH. The corresponding lack of TiO implies a metal defficiency in the secondary. Confirmation and further exploration of these features will provide important insight into abundance peculiarities related to the evolution of close binaries, as AL Com sits at the critical juncture of the orbital period minimum in evolution. Theoretical models predict systems that start at high mass should ultimately evolve to the period minimum, after which the secondary becomes a degenerate low mass (brown dwarf-like) star. The low mass transfer rate in AL Com allows us a rare glimpse into the stellar properties that are affected by mass transfer scenarios in comparison to normal field M dwarfs and brown dwarfs. Title: Magnetic Activity in Low Mass Stars and Brown Dwarfs Authors: Hawley, S.; Reid, I. N.; Gizis, J. Bibcode: 2000ASPC..212..252H Altcode: 2000fgpc.conf..252H No abstract at ADS Title: New light on dark stars. Red dwarfs, low-mass stars, brown dwarfs. Authors: Reid, I. N.; Hawley, S. L. Bibcode: 2000nlod.book.....R Altcode: This book presents a comprehensive discussion of both the astrophysical structure of individual M dwarf and brown dwarf star, and their collective statistical properties as a Galactic stellar population. The first section of the book discusses M dwarfs and brown dwarfs as individual objects - their observational properties, formation, internal structure and atmospheres. The second section deals with M dwarfs from the Galactic perspective - the number of stars, their possible contribution to dark matter and the missing mass and their use as probes of the stellar populations that make up our Galaxy. Contents: (1) Astronomical concepts. (2) Basic observational properties of low-mass dwarfs. (3) The structure, formation and evolution of low-mass stars and brown dwarfs. (4) The photosphere. (5) Stellar activity. (6) A Galactic structure primer. (7) The stellar luminosity function. (8) The mass function. (9) Brown dwarfs: new light on dark stars. (10) Extrasolar planets. (11) M dwarfs in the Galactic halo. Appendix: The 8 parsec sample. Title: New light on dark stars : red dwarfs, low mass stars, brown dwarfs Authors: Reid, Neill; Hawley, Suzanne L. Bibcode: 2000nlds.conf.....R Altcode: No abstract at ADS Title: Properties of M Dwarfs in Clusters and the Field Authors: Hawley, S. L.; Reid, I. N.; Tourtellot, J. G. Bibcode: 2000vlms.conf..109H Altcode: No abstract at ADS Title: Dynamic Models of Optical Emission in Impulsive Solar Flares Authors: Abbett, William P.; Hawley, Suzanne L. Bibcode: 1999ApJ...521..906A Altcode: No abstract at ADS Title: Some Astronomical Performance Advantages of Off-Axis Telescopes Authors: Kuhn, J. R.; Hawley, S. L. Bibcode: 1999PASP..111..601K Altcode: Measurements requiring very high photometric dynamic range, like astronomical observations of faint objects near bright sources (e.g., extrasolar planet detection), are often limited by the scattered light characteristics of the telescope. Although the light-gathering power of recently built telescopes has increased dramatically, their scattered light performance has not. We compare models and measurements of telescope scattered light and discuss some of the scientific and technical issues that suggest how a low scattered light design could extend the scientific capabilities of moderate (4 m aperture) telescopes. Title: Low-Mass Stars in Open Clusters. I. NGC 2516 and NGC 3680 Authors: Hawley, Suzanne L.; Tourtellot, Jonathan G.; Reid, I. Neill Bibcode: 1999AJ....117.1341H Altcode: We have obtained photometric and spectroscopic observations of low-mass stars in the young cluster NGC 2516 and the older cluster NGC 3680. Our observations extend the membership surveys approximately 6 mag fainter than previous studies in these clusters. Using fiducial main sequences representative of the cluster metallicities, we present candidate membership lists and use these to investigate the magnetic activity and luminosity functions in the clusters. NGC 2516 has many active M dwarfs and their properties are similar to those in other young clusters. The dMe stars tend to lie above/red of the fiducial main sequence in an M_V versus V-I color-magnitude diagram. Using spectroscopic observations of the CaOH band at 6230 Å, we show that CaOH is shallower in dMe stars compared with dM stars at the same color. The absolute magnitudes of the dMe stars and dM stars can be brought into agreement when CaOH is used as the temperature indicator, which indicates that the magnetic activity is affecting the V-I color in these stars. The activity strength, measured by log (L_Hα/L_bol), increases toward lower mass stars, in agreement with X-ray and chromospheric results in other young clusters. A few anomalous stars with low activity strength were found, in contrast to other young clusters. Comparison with a recent X-ray survey of NGC 2516 revealed very few low-mass stars with X-ray emission, indicating that low-mass cluster stars probably cannot explain the many X-ray sources without optical counterparts in the survey. The luminosity function for NGC 2516 shows that the cluster is quite extended on the sky, and mass segregation and preferential evaporation of certain low-mass stars are probably occurring. The NGC 3680 observations are consistent with a truncation of the cluster at ~1 M_solar (M_V<~5-6) stars. The absence of low-mass members indicates extensive dynamical evolution or a deviation from a typical initial mass function for this cluster. Title: Mass Segregation and the Initial Mass Function of Low Mass Stars in Open Clusters Authors: Tourtellot, Jonathan; Hawley, Suzanne L.; Reid, I. Neill Bibcode: 1999noao.prop..368T Altcode: The observed luminosity function of low mass stars in an open cluster provides information about the initial mass function (IMF) and the dynamical evolution of that cluster. Our previous survey of open clusters has revealed three clusters with interesting low mass star luminosity functions. We propose to observe these clusters over a much greater spatial extent, and to deeper magnitude limits, than has previously been possible. These data will provide us with complete samples of candidate members out to a large radius from the cluster center. We will use the samples to investigate the mass segregation, dynamical evolution and initial mass functions of the clusters. Title: CCDPHOT Photometry of Extremely Metal-Poor Stars Authors: Anthony-Twarog, B. J.; Beers, T. C.; Hawley, S. L.; Sarajedini, A.; Twarog, B. A. Bibcode: 1999ASPC..189..192A Altcode: 1999pcp..conf..192A No abstract at ADS Title: Chromospheric Activity in Low Mass Stars: Observational Results from Clusters and the Field Authors: Hawley, S. L.; Reid, I. N.; Gizis, J. E.; Byrne, P. B. Bibcode: 1999ASPC..158...63H Altcode: 1999ssa..conf...63H No abstract at ADS Title: Brown Dwarfs in the Hyades and Beyond? Authors: Reid, I. Neill; Hawley, Suzanne L. Bibcode: 1999AJ....117..343R Altcode: 1998astro.ph.11347R We have used both the Low-Resolution Imaging Spectrograph and the High Resolution Echelle Spectrograph on the Keck telescopes to obtain spectra of 12 candidate members of the Hyades identified by Leggett & Hawkins. All of the objects are chromospherically active, late-type M dwarfs, with Hα equivalent widths varying from 1 to 30 Å. Based on our measured radial velocities, the level of stellar activity, and other spectroscopic features, only one of the 12 stars has properties consistent with cluster membership. We consider how this result affects estimates of the luminosity and mass function of the Hyades. Five of the 11 field stars have weak K I lambdalambda7665, 7699 and CaH absorption as compared with M dwarf standards of the same spectral type, suggesting a lower surface gravity. Two of these sources, LH 0416+14 and LH 0419+15, exhibit significant lithium 6708 Å absorption. Based partly on parallax measurements by the US Naval Observatory (Harris et al.), we identify all five as likely to be young, pre-main-sequence objects in or near the Taurus-Auriga association at distances of between 150 and 250 pc. A comparison with theoretical models of pre-main-sequence stars indicates masses of less than 0.05 M_solar. Title: Dynamical Solar Flare Model Atmospheres Authors: Abbett, W. P.; Hawley, S. L. Bibcode: 1999ASPC..158..212A Altcode: 1999ssa..conf..212A No abstract at ADS Title: The absolute magnitudes of RR Lyraes from HIPPARCOS parallaxes and proper motions Authors: Fernley, J.; Barnes, T. G.; Skillen, I.; Hawley, S. L.; Hanley, C. J.; Evans, D. W.; Solano, E.; Garrido, R. Bibcode: 1998A&A...330..515F Altcode: We have used HIPPARCOS proper motions and the method of Statistical Parallax to estimate the absolute magnitude of RR Lyrae stars. In addition we used the HIPPARCOS parallax of RR Lyrae itself to determine it's absolute magnitude. These two results are in excellent agreement with each other and give a zero-point for the RR Lyrae M_v,[Fe/H] relation of 0.77+/-0.15 at [Fe/H]=-1.53. This zero-point is in good agreement with that obtained recently by several groups using Baade-Wesselink methods which, averaged over the results from the different groups, gives M_v = 0.73+/-0.14 at [Fe/H]=-1.53. Taking the HIPPARCOS based zero-point and a value of 0.18+/-0.03 for the slope of the M_v,[Fe/H] relation from the literature we find firstly, the distance modulus of the LMC is 18.26+/-0.15 and secondly, the mean age of the Globular Clusters is 17.4+/-3.0 GYrs. These values are compared with recent estimates based on other "standard candles" that have also been calibrated with HIPPARCOS data. It is clear that, in addition to astrophysical problems, there are also problems in the application of HIPPARCOS data that are not yet fully understood. Table 1, which contains the basic data for the RR Lyraes, is available only at CDS. It may be retrieved via anonymous FTP at cdsarc.u-strasbg.fr (130.79.128.5) or via the Web at http://cdsweb.u-strasbg.fr/Abstract.html Title: Coordinated Observations of Stellar Flares on AD Leo Authors: Hawley, Suzanne L. Bibcode: 1998euve.prop....4H Altcode: We will obtain EUVE observations of the dMe star AD Leo during periods of quiescence and during flares to study the physics of atmospheric heating in flare stars. These observations will be coordinated with our approved FUSE Guest Observer program and with ground-based observations including multicolor photometry and high resolution optical spectroscopy. The EUVE and optical light curves obtained during flares will allow us to determine the coronal loop length and flare coverage area on the stellar surface. The combination of EUVE, FUSE and optical spectra will allow us to determine the structure and evolution of temperature and density in the corona, transition region, and chromosphere, providing unique constraints on our detailed theoretical and numerical models of flare evolution corresponding to various heating mechanisms. Title: The Absolute Magnitudes of RR Lyrae Stars Authors: Fernley, J. D.; Barnes, T. G.; Skillen, I.; Hawley, S. L.; Hanley, C. J.; Evans, D. W.; Solano, E.; Garrido, R. Bibcode: 1998ASPC..135..385F Altcode: 1998hcsp.conf..385F We estimate the absolute magnitude of RR Lyrae stars using the recently published HIPPARCOS data. Comparisons are made with previous work on RR Lyrae absolute magnitudes and the impact on the distance scale is discussed. Title: Extreme Ultraviolet Explorer Spectra of the 1993 March Flares on AD Leonis: The Differential Emission Measure and Implications for Coronal Structure Authors: Cully, Scott L.; Fisher, George H.; Hawley, Suzanne L.; Simon, Theodore Bibcode: 1997ApJ...491..910C Altcode: The flare star AD Leonis was observed by the Extreme Ultraviolet Explorer (EUVE) from 1993 March 1 to 3 UT. Two flares were detected by the EUVE Deep Survey detector and spectrometer and also seen in optical photometry on 1993 March 2 UT. The DS Lexan/boron-band and optical results have been discussed in the previous paper by Hawley et al. In this paper, we describe the spectra observed by EUVE during quiescence, the peaks of the flares, and the decay phase following the first flare and analyze the spectra to investigate the stellar atmospheric structure during these time periods.

The spectra show that the observed EUV emission from AD Leo is dominated by iron lines from a hot coronal plasma. Two methods were used to estimate the differential emission measure distribution (DEM) of the stellar corona. In the ``Pottasch'' method, we fitted Gaussian line profiles to the strongest lines in the spectra and estimated the DEM at the formation temperature of those lines. Upper limits to the DEM were obtained in the case of no detection. We also used a regularized inversion technique, together with a weighting scheme based on information contained in the plasma-emission model and on the signal-to-noise ratio of the data, to find the DEM. The weighting was designed to prevent the noisy pixels in our low-signal-to-noise ratio data from dominating the solution. The results produced by the two methods are consistent in the temperature regimes where strong lines are present. The inversion method provides additional information where no strong single lines dominate the spectra. The ability to use lines from the entire wavelength region covered by the spectra allowed us to investigate the hydrogen column NH and iron abundance [Fe/H].

We found that [Fe/H] in the corona of AD Leo was essentially unconstrained by our data, but NH was well determined, yielding NH ~ (3 +/- 1) × 1018 cm-2. We assumed both a solar-coronal value of [Fe/H] and a value one tenth of this and computed the DEM distribution of the stellar corona for both cases.

The DEM of the quiescent corona is dominated by a broad plateau of emission ranging from 106.8 to 107.2 K, with the DEM of plasma near 106.2 K about an order of magnitude less. We interpret the plateau of the DEM in terms of a broad distribution of loops with differing peak temperatures. We discuss and compare these results with those of Giampapa et al., who analyzed ROSAT soft X-ray data from AD Leo taken during a different time period.

The DEM of the flare plasma is strongly peaked at temperatures greater than 107 K, indicative of hot flare loops, while that of the decay phase consists of a smaller peak at temperatures less than 107 K, as might be expected from the cooling and condensation of previously heated flare loops. These results are consistent with a flare model that includes strong evaporation and condensation as in our previous paper. The EUVE spectral analysis leads to lower peak flare temperatures than those used in our previous paper, but the basic conclusion reached--that the dominant flaring emission originates from long loops with L ~ R* and with peak flare densities ranging from 109 to 1011 cm-3--remains unchanged. This conclusion is not qualitatively affected by the value of [Fe/H] used in our DEM analysis. Title: CCD photometry of late-type stars in the young open cluster IC 2602 Authors: Foster, D. C.; Byrne, P. B.; Hawley, S. L.; Rolleston, W. R. J. Bibcode: 1997A&AS..126...81F Altcode: We present the results of VRI photometry of the young open cluster IC 2602. Two 15 arcmin times 15 arcmin fields were observed in February and May 1991 using the 1-m Swope telescope at Las Campanas. Using theoretical isochrones obtained from \cite[D'Antona & Mazzitelli (1994)]{dam94}, and allowing for observational and other uncertainties, we identify 78 primary candidate members with 12<V<18.5 from their positions on colour-magnitude diagrams. We compare the cluster field with an offset field of similar galactic latitude and estimate the contamination due to background stars to be large, >= 50%, as might be expected given its low galactic latitude. We also compare our photometry with that given for the X-ray detected stars of \cite[Randich et al. (1995)]{ran95}. We present complimentary narrow band H alpha photometry for a subset of the stars. Title: VizieR Online Data Catalog: RR Lyrae parallaxes & proper motions (Fernley+ 1998) Authors: Fernley, J.; Barnes, T. G.; Skillen, I.; Hawley, S. L.; Hanley, C. J.; Evans, D. W.; Solano, E.; Garrido, R. Bibcode: 1997yCat..33300515F Altcode: We have used HIPPARCOS proper motions and the method of Statistical Parallax to estimate the absolute magnitude of RR Lyrae stars. In addition we used the HIPPARCOS parallax of RR Lyrae itself to determine it's absolute magnitude. These two results are in excellent agreement with each other and give a zero-point for the RR Lyrae Mv,[Fe/H] relation of 0.77+/-0.15 at [Fe/H]=-1.53. This zero-point is in good agreement with that obtained recently by several groups using Baade-Wesselink methods which, averaged over the results from the different groups, gives Mv=0.73+/-0.14 at [Fe/H]=-1.53. Taking the HIPPARCOS based zero-point and a value of 0.18+/-0.03 for the slope of the Mv,[Fe/H] relation from the literature we find firstly, the distance modulus of the LMC is 18.26+/-0.15 and secondly, the mean age of the Globular Clusters is 17.4+/-3.0 GYrs. These values are compared with recent estimates based on other "standard candles" that have also been calibrated with HIPPARCOS data. It is clear that, in addition to astrophysical problems, there are also problems in the application of HIPPARCOS data that are not yet fully understood.

(2 data files). Title: Hamilton Echelle Spectroscopy of the 1993 March 6 Solar Flare Authors: Johns-Krull, Christopher M.; Hawley, Suzanne L.; Basri, Gibor; Valenti, Jeff A. Bibcode: 1997ApJS..112..221J Altcode: We report on a successful program that used the Hamilton echelle spectrograph and the coudé auxiliary telescope at Lick Observatory to take spectra of solar flares. Our observations consist of high-resolution (λ/δλ ~ 48,000) spectra covering the entire optical region from approximately 3800 to 9000 Å in each exposure. These are the first time-resolved high-resolution optical spectra of this type obtained for a solar flare.

On 1993 March 6 we observed a relatively large (GOES class M7.7) solar flare event. Our sequence of observations began before flare maximum and continued for more than 1 hr. We present our high signal-to-noise spectra and compare them with similar stellar flare observations. We find that the hydrogen-emitting layers in flares on the Sun differ markedly from those in flares on dMe stars, though the total energy emitted in various emission lines can be rather similar. We also find that the amount of energy released in the optical emission lines is similar to that emitted in soft X-rays. We find evidence for Stark broadening in the Balmer lines for members lower in the series than reported in earlier studies. This appears to have occurred because the optical depth in the Balmer lines is lower than in previously reported flares. Early in the flare, the Hα and Hβ line profiles appear to be asymmetric as a result of absorption by chromospheric material expanding upward into the corona. We also examine solar flare model atmospheres synthesized with the non-LTE code MULTI and find that our observations can be generally understood in terms of equilibrium models of electron-beam- and X-ray-heated chromospheres in equilibrium with coronal loops in which the pressure is rather high; however, there remain marked differences between the theoretical predictions and our observations, implying that substantial refinement of the models is in order. Several photospheric lines show flare enhancements as well. The temporal behavior of these line enhancements is identical to that of the chromospheric lines, but there is no indication that significant flare heating penetrates to continuum formation depths.

Based on observations obtained at Lick Observatory, which is operated by the University of California. Title: Non-LTE Radiative-hydrodynamic Models of Solar Flares Authors: Abbett, William P.; Hawley, Suzanne L. Bibcode: 1997BAAS...29Q1120A Altcode: No abstract at ADS Title: The Absolute Magnitudes of RR Lyrae Stars Authors: Fernley, J.; Barnes, T. G.; Skillen, I.; Hawley, S. L.; Hanley, C.; Evans, D. W.; Solano, E.; Garrido, R. Bibcode: 1997ESASP.402..635F Altcode: 1997hipp.conf..635F Using firstly, the Hipparcos proper motions and the method of Statistical Parallax and secondly, the Hipparcos parallax of RR Lyrae itself and thirdly, the Baade-Wesselink results from the literature we find the zero-point of the RR Lyrae absolute magnitude - metallicity relation to be M_v = 0.72 +/- 0.10 at [Fe/H] = -1.52. The small error on this zero-point reflects the remarkably good agreement between the three (independent) methods. Taking a value of 0.18 +/- 0.03 for the slope of the relation from the literature we obtain a distance modulus of the LMC of 18.31. This is compared to other recent determinations of the distance to the LMC. Title: Erratum: Evaporation, Tidal Disruption, and Orbital Decay of Star Clusters in a Galactic Halo Authors: Capriotti, E. R.; Hawley, S. L. Bibcode: 1997ApJ...483..984C Altcode: In § 2 of the recent paper ``Evaporation, Tidal Disruption, and Orbital Decay of Star Clusters in a Galactic Halo'' by E. R. Capriotti and S. L. Hawley (ApJ, 464, 765 [1996]), equation (1) contains a misprint. It should read rt=2r/3 [(Mc)/(AMH(r))]1/3/[1-r/(AMH(r)) (dMH(r))/dr]1/3 , (1)where the difference from the published version is that an A replaces the 3 in the denominator of the last term. The authors regret the error. Title: VizieR Online Data Catalog: Palomar/MSU nearby star spectroscopic survey (Hawley+ 1997) Authors: Reid, I. N.; Hawley, S. L.; Gizis, J. E. Bibcode: 1997yCat.3198....0R Altcode: The Third Catalogue of Nearby Stars (Gliese & Jahreiss, "Preliminary Version of the third Catalogue of Nearby Stars" (CNS3), 1991, catalog <V/70>) includes over 1850 stars which lie north of Dec.= -30° and are either identified as spectral type M, or are unclassified but with an absolute visual magnitude estimate MV > +8.0. Although there is no uniformity in selection criteria, and many of the stars lack basic data (radial velocities, spectral types, accurate photometry), the observational properties of these stars underlie most estimates of the fundamental characteristics of the Galactic Disk. We have obtained optical spectroscopy of 1746 of the 1876 stars -- the remaining 130 are binary companions of brighter stars and inaccessible to our observations. These spectra allow us, first, to exclude 61 stars as either degenerates or as misclassified earlier-type (B-K) stars lying beyond the 25 pc limit; to establish radial velocities accurate to ±10km/s for all stars confirmed as late-type dwarfs; to determine spectral types and absolute magnitudes from the TiO bandstrength, allowing more accurate distance estimates for stars with inaccurate (or no) trigonometric parallax measurements; and to identify stars with Hα emission (chromospherically active stars) and with strong CaH absorption (perhaps including some metal-poor disk subdwarfs). We have determined the nearby-star luminosity function from complete samples derived by applying both the distance limits defined by Wielen (1974, Highlights of Astron. 3, 395) and by using limits derived from our own analysis. Spectroscopic data for the southern stars (Dec.<-30°) in the PMSU survey are also presented. The data were combined with the data from paper I to obtain a list of all the magnetically active dMe stars in the survey.

(11 data files). Title: The Palomar/MSU Nearby Star Spectroscopic Survey.II.The Southern M Dwarfs and Investigation of Magnetic Activity Authors: Hawley, Suzanne L.; Gizis, John E.; Reid, Neill I. Bibcode: 1997AJ....113.1458H Altcode: No abstract at ADS Title: VizieR Online Data Catalog: IC 2602 VRI photometry (Foster+ 1997) Authors: Foster, D. C.; Byrne, P. B.; Hawley, S. L.; Rolleston, W. R. J. Bibcode: 1997yCat..41260081F Altcode: We present the results of VRI photometry of the young open cluster IC 2602. Two 15x15arcmin2 fields were observed in February and May 1991 using the 1-m Swope telescope at Las Campanas. Using theoretical isochrones obtained from D'Antona & Mazzitelli (1994ApJS...90..467D), and allowing for observational and other uncertainties, we identify 78 primary candidate members with 12<V<18.5 from their positions on colour-magnitude diagrams. We compare the cluster field with an offset field of similar galactic latitude and estimate the contamination due to background stars to be large, >=50%, as might be expected given its low galactic latitude. We also compare our photometry with that given for the X-ray detected stars of Randich et al. (1995A&A...300..134R) present complimentary narrow band Hα photometry for a subset of the stars. (1 data file). Title: Tidal Streams from the Carina and Draco Dwarf Galaxies Authors: Smith, H. A.; Kuhn, J. R.; Hawley, S. L. Bibcode: 1997ASPC..127..163S Altcode: 1997pmga.conf..163S No abstract at ADS Title: The Palomar/MSU Nearby Star Spectroscopic Survey.II.The Southern M Dwarfs and Investigation of Magnetic Activity Authors: Hawley, Suzanne L.; Gizis, John E.; Reid, I. Neill Bibcode: 1996AJ....112.2799H Altcode: Spectroscopic data for the southern stars (δ<-30) in the PMSU survey are presented. The data were combined with the data from Paper I [Reid, Hawley & Gizis, AJ, 110, 1838 (1995)] to obtain a list of all the magnetically active dMe stars in the survey. The incidence of activity increases monotonically toward later spectral type, reaching a level of 60% at spectral types >M5. This is not a selection effect, since the chromospheric activity level (LHα/Lbol) remains high throughout the spectral type range where the incidence is increasing. At very late types, there is evidence that the mean activity level drops in both chromospheric and coronal emission. The ratio between the chromospheric and coronal emission levels remains constant, indicating that the heating mechanism is not changing. There is little or no dependence of the chromospheric activity level on rotational velocity (υ sin i). The color-magnitude diagrams in both MV and MK show strong evidence for a break between spectral types M3-MS, in both the dMe and dM stars. The dMe stars at earlier types than M3 are about 0.5 magnitudes brighter than dM stars of the same spectral type in both MV and MK. They also are slightly (≤0. 1 magnitude) redder. Both the Hyades and IC 2602 clusters show the same absolute magnitude effect for the early type dMe stars. The Balmer decrement varies widely among the dMe field stars, in contrast to the Hyades stars. The photospheric TiO bands show detailed structure which depends on the chromospheric activity level of the star. These spectroscopic signatures will provide useful constraints on atmospheric models. A rigorous maximum likelihood analysis of the kinematic properties of a complete subs ample of the survey shows that the dMe stars are, as a whole, kinematically younger than the dM stars. Subsets of the dM sample also show that the early type dM stars are younger than the late dM stars, suggesting that the dMe phenomenon lasts longer in later type stars. This provides a natural explanation for the increase in the incidence of activity toward later spectral types. Title: The Absolute Magnitude and Kinematics of RR Lyrae Stars Via Statistical Parallax Authors: Layden, Andrew C.; Hanson, Robert B.; Hawley, Suzanne L.; Klemola, Arnold R.; Hanley, Christopher J. Bibcode: 1996AJ....112.2110L Altcode: 1996astro.ph..8108L We present new statistical parallax solutions for the absolute magnitude and kinematics of RR Lyrae stars. We have combined new proper motions from the Lick Northern Proper Motion program with new radial velocity and abundance measures to produce a data set that is 50% larger, and of higher quality, than the data sets employed by previous analyses. Based on an a priori kinematic study, we separated the stars into halo and thick disk sub-populations. We performed statistical parallax solutions on these sub-samples, and found Mv(RR)=+0.71±0.12 at <[Fe/H]>=-1.61 for the halo (162 stars), and Mv(RR)=+0.79±0.30 at <[Fe/H]>=-0.76 for the thick disk (51 stars). The solutions yielded a solar motion <V>=-2l0±12 km s-1 and velocity ellipsoid (σU,σV,σW) = (168±13, l02±8, 97±7)km s-1 for the halo. The values were <V>=-48±9km s-1 and (σU,σV,σW) = (56±8,51±8,31±5) km s-1 for the thick disk. Both are in good agreement with estimates of the halo and thick disk kinematics derived from both RR Lyrae stars and other stellar tracers. Monte Carlo simulations indicated that the solutions are accurate, and that the errors may be smaller than the estimates above. The simulations revealed a small bias in the disk solutions, and appropriate corrections were derived. The large uncertainty in the disk Mv(RR) prevents ascertaining the slope of the Mv(RR)-[Fe/H] relation. Using a zero point defined by our halo solution and adopting a slope of 0.15 mag dex-1, we find that (1) the distance to the Galactic Center is 7.6±0.4 kpc; (2) the mean age of the 17 oldest Galactic globular clusters is 16.522.1/11.9 Gyr; and (3) the distance modulus of the LMC is 18.28t 0.13 mag. Estimates of H0 which are based on an LMC distance modulus of 18.50 (e.g., Cepheid studies) increase by 10% if they are recalibrated to match, our LMC distance modulus. Title: Tidal Disruption and Tails from the Carina Dwarf Spheroidal Galaxy Authors: Kuhn, J. R.; Smith, Horace A.; Hawley, Suzanne L. Bibcode: 1996ApJ...469L..93K Altcode: New photometry of regions beyond the classical tidal radius of Carina exposes a Carina-like stellar distribution that is about 1% of the central surface density and which extends at least as far as 2 deg (3.5 kpc) from Carina's center. The detections of a spatially extended RR Lyrae distribution, and a significant Carina-like stellar population at large central distances confirm predictions of the time-dependent tidal interaction model and suggest that Carina is not in virial equilibrium. Title: Teaching materials: stellar atmospheres/radiative transfer. Authors: Hawley, S. L.; Ayres, T. R. Bibcode: 1996BAAS...28Q.883H Altcode: No abstract at ADS Title: Evaporation, Tidal Disruption, and Orbital Decay of Star Clusters in a Galactic Halo Authors: Capriotti, Eugene R.; Hawley, Suzanne L. Bibcode: 1996ApJ...464..765C Altcode: We consider the orbital evolution and tidal evaporation and disruption of globular clusters and dwarf spheroidal galaxies in the gravitational potential of an isothermal dark matter halo, consistent with that predicted by current observations of flat rotation curves in spiral galaxies. The rate of orbital decay due to dynamical friction and mass- loss rates including halo-induced tidal effects are computed self consistently using a semi-analytical model. A wide range of cluster masses and central mass concentrations for both circular and radial orbits was considered. We find that the high-mass clusters (M_c_ ~> 10^7^ M_sun_) suffer substantial to complete orbital decay due to dynamical friction, while the low-mass clusters (M_c_ <~ 10^5^ M_sun_) suffer substantial to complete evaporation or disruption. The mass contribution to the halo, per cluster, is small in both cases. Intermediate-mass clusters of high central mass concentration survive for a Hubble time, while intermediate and high-mass clusters of low central mass concentration evaporate or disrupt and may have contributed a large fraction of the mass in the halo. For all initial orbital sizes and cluster concentrations the mass range for surviving clusters is narrower for radial orbits, and the halo stars contributed by these clusters should have highly eccentric orbits. Our results show that the current globular cluster population is, to a large extent, consistent with that determined from our simple approximation, which considers only the gravitational effects of an isothermal halo. Title: The Palomar/MSU Nearby-Star Spectroscopic Survey. I. The Northern M Dwarfs-Bandstrengths and Kinematics Authors: Reid, I. Neill; Hawley, Suzanne L.; Gizis, John E. Bibcode: 1996AJ....111.2469R Altcode: No abstract at ADS Title: Teaching Materials: Stellar Atmospheres/Radiative Transfer Authors: Hawley, S. L.; Ayres, T. R. Bibcode: 1996AAS...188.3905H Altcode: 1996BAAS...28..883H We will present a selection of modern teaching materials for courses in Stellar Atmospheres and Radiative Transfer that have been collected from a wide variety of sources. We will provide brief synopses of each book, or set of of notes, and endeavor to compare and contrast the different presentations of the material. One of the newer additions to the literature is ``Radiative Transfer in Stellar Atmospheres,'' lecture notes from R.J. Rutten based on courses taught at Utrecht University. In addition, I. Hubeny and D. Mihalas presently are writing a new edition of Mihalas' famous ``Stellar Atmospheres.'' Other books we are aware of range from the planning stages to near completion. We will emphasize the diversity of styles and presentation techniques, but will try to make clear the central themes around which any successful Stellar Atmospheres/Radiative Transfer course must be built. Title: Observations of Tidal Disruption of the Carina Dwarf Spheroidal Galaxy Authors: Kuhn, J. R.; Smith, H. A.; Hawley, S. L. Bibcode: 1996AAS...188.7705K Altcode: 1996BAAS...28S.954K New observations of the Carina dwarf spheroidal galaxy have been obtained at angular distances as far as 2 degrees from its center. Along the Carina major axis we detect RR Lyraes at Carina's MW distance, but well beyond its classical tidal radius. Color-magnitude observations show the existence of a surface density of Carina-population stars which is a few percent of the central density as far as 3.5kpc away from the dS center along its major axis. These measurements support the model of Carina as a tidally disrupting galaxy with no excess dark matter. Title: Observations of tidal disruption of the Carina dwarf spheroidal galaxy. Authors: Kuhn, J. R.; Smith, H. A.; Hawley, S. L. Bibcode: 1996BAAS...28..954K Altcode: No abstract at ADS Title: Moving Groups, Stellar Streams and Phase Space Substructure in the Galactic Halo Authors: Majewski, S. R.; Hawley, S. L.; Munn, J. A. Bibcode: 1996ASPC...92..119M Altcode: 1996fogh.conf..119M We have been exploring the phase space and metallicity distributions of stars in the North Galactic Pole field SA 57. The data are deep (B ~ 22.5) proper motions and photometry, combined with Mayall 4-m spectroscopy using the HYDRA multifiber system to brighter (B ~ 19.5) limits. Our early spectroscopic results confirmed the existence of a retrograde rotating, halo moving group in this field. We have since obtained many more spectra, and we find the halo stars in our survey to show a high degree of clumping in their U- V-W-[Fe/H] distributions. From our data we conclude that (1) the halo is not a dynamically relaxed system, (2) phase space substructure could account for differences in halo kinematics derived from surveys along different lines of sight, and (3) the halo field star population may be derived predominantly from the accretion of stellar agglomerations, most likely dwarf galaxies. The latter conclusion agrees with that of Preston et al. (1994) from their work on blue, metal-poor stars. Title: Statistical Parallax Analysis of RR Lyrae Stars Authors: Hawley, Suzanne L.; Hanley, Christopher; Layden, Andrew C.; Hanson, Robert B. Bibcode: 1996ASPC...92..188H Altcode: 1996fogh.conf..188H We present results from a new statistical parallax analysis of the field RR Lyrae stars. New and improved data, together with a careful population separation, allow us to investigate the dependence of the RR Lyrae absolute magnitude on metallicity. Title: Evaporation, Tidal Disruption, and Orbital Decay of Star Clusters in a Galactic Halo Authors: Capriotti, Eugene R.; Hawley, Suzanne L.; Hamlin, Michael Bibcode: 1996ASPC...92..487C Altcode: 1996fogh.conf..487C We consider the orbital evolution and tidal evaporation and disruption of globular clusters in the gravitational potential of an isothermal dark matter halo using a semi-analytic model. Our results show that intermediate mass clusters of high central concentration survive for a Hubble time, while low mass clusters tend to evaporate or disrupt, and high mass clusters suffer orbital decay due to dynamical friction. The current globular cluster population is, to a large extent, consistent with that determined from our simple model. Title: Absolute Proper Motions to B approximately 22.5: Large-Scale Streaming Motions and the Structure and Origin of the Galactic Halo Authors: Majewski, Steven R.; Munn, Jeffrey A.; Hawley, Suzanne L. Bibcode: 1996ApJ...459L..73M Altcode: With an enlarged sample of radial velocities, we explore the phase-space and metallicity distributions for a sample of dwarf stars with distances up to 8 kpc in a deep north Galactic pole proper motion survey. We find that the halo stars in the sample are concentrated into clumps in the combined phase-space and metallicity distribution, one of the most prominent clumps representing a retrograde, predominantly metal-poor ([Fe/H] < -0.8) stream moving toward the Galactic plane. These new data reveal that (1) the halo is not dynamically mixed but presently contains a significant fraction of stars with membership in correlated stellar streams, (2) phase-space substructure might account for differences in halo kinematics derived among surveys along different lines of sight, and (3) a significant fraction of the halo field star population may be derived from the accretion of stellar agglomerations (e.g., star clusters, satellite galaxies, or Searle & Zinn "fragments"). Title: All telescopes great and small. Authors: Hawley, S. L. Bibcode: 1996Mercu..25a..13H Altcode: The 1990s have been the era of the super-telescope, of 8- to 10-meter mirrors that see to the edge of the observable universe. To some astronomers and their benefactors, the 1- or 2-meter instruments are now expendable. They are not. Title: Low-mass stars in old open clusters Authors: Reid, I. N.; Hawley, S. L. Bibcode: 1996ASPC..109..383R Altcode: 1996csss....9..383R No abstract at ADS Title: Large classes and quality instruction: the "interrupted lecture". Authors: Hufnagel, B.; Hawley, S. L.; Stein, R.; Wilhelm, R. Bibcode: 1996BAAS...28.1203H Altcode: No abstract at ADS Title: Continued analysis of EUVE and optical observations of a flare on AD Leonis. Authors: Cully, S. L.; Fisher, G. H.; Hawley, S. L.; Simon, T. Bibcode: 1996aeu..conf..153C Altcode: The flare star AD Leo was observed by EUVE from 1993 March 1 - March 3 UT. A flare was detected by the EUVE DS/S and seen in optical photometry on 1993 March 2 UT. The authors summarize an analysis of the flare's physical parameters, and present differential emission measure (DEM) curves calculated for the quiescent, flare peak and flare decay phases of the observation. Title: Continued Analysis of EUVE and Optical Observations of a Flare on AD Leonis Authors: Gully, S. L.; Fisher, G. H.; Hawley, S. L.; Simon, T. Bibcode: 1996aeu..conf..153G Altcode: 1996IAUCo.152..153G No abstract at ADS Title: VRI photometry of the young open cluster IC 2602 Authors: Foster, D. C.; Byrne, P. B.; Rolleston, W. R. J.; Hawley, S. L. Bibcode: 1996ASPC..109..357F Altcode: 1996csss....9..357F No abstract at ADS Title: Simultaneous Extreme-Ultraviolet Explorer and Optical Observations of AD Leonis: Evidence for Large Coronal Loops and the Neupert Effect in Stellar Flares Authors: Hawley, Suzanne L.; Fisher, George H.; Simon, Theodore; Cully, Scott L.; Deustua, Susana E.; Jablonski, Marek; Johns-Krull, Christopher M.; Pettersen, Bjorn R.; Smith, Verne; Spiesman, William J.; Valenti, Jeffrey Bibcode: 1995ApJ...453..464H Altcode: We report on the first simultaneous Extreme-Ultraviolet Explorer (EUVE) and optical observations of flares on the dMe flare star AD Leonis. The data show the following features:

1. Two flares (one large and one of moderate size) of several hours duration were observed in the EUV wavelength range;

2. Flare emission observed in the optical precedes the emission seen with EUVE;

3. Several diminutions (DIMs) in the optical continuum were observed during the period of optical flare activity.

To interpret these data, we develop a technique for deriving the coronal loop length from the observed rise and decay behavior of the EUV flare. The technique is generally applicable to existing and future coronal observations of stellar flares. We also determine the pressure, column depth, emission measure, loop cross- sectional area, and peak thermal energy during the two EUV flares, and the temperature, area coverage, and energy of the optical continuum emission.

When the optical and coronal data are combined, we find convincing evidence of a stellar "Neupert effect" which is a strong signature of chromospheric evaporation models. We then argue that the known spatial correlation of white-light emission with hard X-ray emission in solar flares, and the identification of the hard X-ray emission with nonthermal bremsstrahlung produced by accelerated electrons, provides evidence that flare heating on dMe stars is produced by the same electron precipitation mechanism that is inferred to occur on the Sun.

We provide a thorough picture of the physical processes that are operative during the largest EUV flare, compare and contrast this picture with the canonical solar flare model, and conclude that the coronal loop length may be the most important factor in determining the flare rise time and energetics. Title: The Palomar/MSU Nearby-Star Spectroscopic Survey. I. The Northern M Dwarfs -Bandstrengths and Kinematics Authors: Reid, I. Neill; Hawley, Suzanne L.; Gizis, John E. Bibcode: 1995AJ....110.1838R Altcode: The Third Catalogue of Nearby Stars (Gliese & Jahreiss Preliminary Version of the third Catalogue of Nearby Stars, 1991) includes over 1850 stars which lie north of δ 30° and are either identified as spectral type M, or are unclassified but with an absolute visual magnitude estimate MV>+8.O. Although there is no uniformity in selection criteria, and many of the stars lack basic data (radial velocities, spectral types, accurate photometry), the observational properties of these stars underlie most estimates of the fundamental characteristics of the Galactic Disk. We have obtained optical spectroscopy of 1746 of the 1876 stars-the remaining 130 are binary companions of brighter stars and inaccessible to our observations. These spectra allow us, first, to exclude 61 stars as either degenerates or as misclassified earlier-type (B - K) stars lying beyond the 25 pc limit; to establish radial velocities accurate to ±10 km s-1 for all stars confirmed as late-type dwarfs; to determine spectral types and absolute magnitudes from the TiO bandstrength, allowing more accurate distance estimates for stars with inaccurate (or no) trigonometric parallax measurements; and to identify stars with Ha emission (chromospherically active stars) and with strong CaH absorption (perhaps including some metal-poor disk subdwarfs). We have determined the nearby-star luminosity function from complete samples derived by applying both the distance limits defined by Wielen (1974) and by using limits derived from our own analysis. In both cases, we find good agreement with Wielen's results to MV ∼+11, but lower densities at the maximum (MV∼+12). The latter analysis results in a luminosity function, ΦCNS, which closely matches photometric parallax analyses for MV<+11 and MV>+14 -- we do not recover the apparent excess of low-luminosity stars inferred from analysis of the 5 pc sample. However, ΦCNS does lie below Φphot at the peak (MV∼12), and we suggest that this offset is caused by the inclusion of unrecognized binaries in the photometric surveys. We have also reanalyzed the local stellar kinematics using the complete sample and find that the velocity distributions show significant departures from single Gaussian velocity dispersions. Title: Tidal Evaporation and Orbital Decay of Star Clusters in a Galactic Halo Authors: Capriotti, E.; Hawley, S. L. Bibcode: 1995AAS...186.4907C Altcode: 1995BAAS...27..882C We consider the evolution of globular clusters and dwarf galaxies under the gravitational influence of an isothermal halo. Evaporation rates are compared to orbital decay rates for a variety of initial cluster masses, central concentrations, and orbital sizes and eccentricities. Clusters which survive for a Hubble time fall into a mass range which depends most crucially on the original orbital parameters. Title: Chromospheric and coronal activity in low-mass Hyades dwarfs Authors: Reid, Neill; Hawley, Suzanne L.; Mateo, Mario Bibcode: 1995MNRAS.272..828R Altcode: We present an extensive survey of the chromospheric and coronal activity among low-mass members of the Hyades open cluster. We have obtained H alpha spectroscopy of 91 probable cluster members, including 23 that lie within three fields for which we have deep ROSAT X-ray observations. 20 of the 23 stars are detected in X-rays; the non-detections are probably not Hyades members. Combining these observations with data from the literature, we find that the mean H alpha to bolometric luminosity ratio log (L_H alpha/L_bol) is constant at a value of ~-3.9 for M_bol>8, with a substantial dispersion and an upper limit of -3.5. The X-ray to bolometric luminosity ratio log (L_x/L_bol) first increases with increasing M_bol, then flattens at a value of ~-3.3 for M_bol>8. Comparing this behaviour with stars in the Pleiades cluster, there are significant differences: first, the log (L_H alpha/L_bol) ratio increases with increasing M_bol while M_bol<10, but appears to turn over sharply at fainter magnitudes, with the lower luminosity stars being nearly an order of magnitude lower in the ratio; secondly, we find no evidence for saturation in the log (L_x/L_bol) ratio; L_x increases monotonically with M_bol, reaching a value of ~-2.5 at M_bol~10. Lower luminosity stars have not yet been detected in X-ray observations. The nearly constant H alpha to H beta ratio in the Hyades stars, coupled with the small range in coronal temperature seen in the X-ray data, suggest that the (presumably magnetically generated) heating rate is nearly constant in the outer atmospheres of these stars. Differences in the relative activity levels are then ascribed to differences in the filling factor of active regions, and in the sizes of the coronal structures. Title: The Frequency of Magnetic Activity in Field M Dwarfs Authors: Hawley, S. L. Bibcode: 1995bmsb.conf..224H Altcode: No abstract at ADS Title: Spectroscopic Survey of Nearby M Dwarfs Authors: Gizis, J.; Reid, N.; Hawley, S. Bibcode: 1994AAS...185.2205G Altcode: 1994BAAS...26.1347G The preliminary version of the Third Catalog of Nearby Stars lists 1736 M-dwarfs within 25 parsecs and another 470 stars of color class 'k-m' or M_v > 8. We have obtained obtained ~ 2 Angstroms resolution spectra of those stars north of declination -30(deg) using the Palomar 60 '' and 200 '' telescopes over the wavelength range lambda lambda 6180-7550. Stars are classified on the basis of the TiO and CaH bands. H alpha emission stars are identified (EW > 1 Angstroms). We have defined volume complete samples on the basis of our distance estimates. Radial velocities (sigma ~ 15 km s(-1) ) and the catalog proper motions provide the full space velocity for the sample. Title: Absolute Proper Motions to B approximately 22.5: Evidence for Kinematical Substructure in Halo Field Stars Authors: Majewski, Steven R.; Munn, Jeffrey A.; Hawley, Suzanne L. Bibcode: 1994ApJ...427L..37M Altcode: Radial velocities have been obtained for six of nine stars identified on the basis of similar distances and common, extreme transverse velocities in the proper motion survey of Majewski (1992) as a candidate halo moving group at the north Galactic pole. These radial velocities correspond to velocities perpendicular to the Galactic plane which span the range -48 +/- 21 to -128 +/- 9 km/sec (but a smaller range, -48 +/- 21 to -86 +/- 19 km/sec, when only our own measurements are considered), significantly different than the expected distribution, with mean 0 km/sec, for a random sample of either halo or thick disk stars. The probability of picking such a set of radial velocities at random is less than 1%. Thus the radial velocity data support the hypothesis that these stars constitute part of a halo moving group or star stream at a distance of approximately 4-5 kpc above the Galactic plane. If real, this moving group is evidence for halo phase space substructure which may be the fossil remains of a destroyed globular cluster, Galactic satellite, or Searle & Zinn (1978) 'fragment.' Title: Comparison of Chromospheric and Coronal Activity in the Hyades and Pleiades Authors: Hawley, S. L.; Reid, I. N. Bibcode: 1994AAS...184.4305H Altcode: 1994BAAS...26..930H We present results from our extensive survey of chromospheric and coronal activity in lower main-sequence members of the Hyades open cluster. We have obtained H alpha spectroscopy of ninety-one probable cluster members, twenty-three of which lie within three fields for which we have deep ROSAT X-ray observations. Twenty of the twenty-three stars are detected. Combining these observations with data from the literature, we find that the mean ratio log (L_alpha / Lbol) is roughly constant for Mbol > 8, with a substantial dispersion. The X-ray-to-bolometric luminosity ratio increases with decreasing Mbol, although the relation may flatten for Mbol > 9. Comparing this behaviour with stars in the Pleiades cluster, there are significant differences: first, the log (L_alpha / Lbol) relation in the Pleiades increases for Mbol < 10, but appears to turn over sharply at fainter magnitudes, with the lower luminosity stars having nearly an order of magnitude lower H alpha luminosity; second, we find no evidence for saturation in the log (L_X / Lbol) ratio. However, none of the lower luminosity Pleiades stars with low H alpha luminosity have X-ray observations. Title: Solar Flare Model Atmospheres Authors: Hawley, Suzanne L.; Fisher, George H. Bibcode: 1994ApJ...426..387H Altcode: Solar flare model atmospheres computed under the assumption of energetic equilibrium in the chromosphere are presented. The models use a static, one-dimensional plane-parallel geometry and are designed within a physically self-consistent coronal loop. Assumed flare heating mechanisms include collisions from a flux of nonthermal electrons and X-ray heating of the chromosphere by the corona. The heating by energetic electrons accounts explicitly for variations of the ionized fraction with depth in the atmosphere. X-ray heating of the chromosphere by the corona incorporates a flare loop geometry by approximating distant portions of the loop with a series of point sources, while treating the loop leg closest to the chromospheric footpoint in the plane-parallel approximation. Coronal flare heating leads to increased heat conduction, chromospheric evaporation and subsequent changes in coronal pressure; these effects are included self-consistently in the models. Cooling in the chromosphere is computed in detail for the important optically thick H I, Ca II and Mg II transitions using the non-local thermodynamic equilibrium (non-LTE) prescription in the program MULTI. Hydrogen ionization rates from X-ray photoionization and collisional ionization by nonthermal electrons are included explicitly in the rate equations. The models are computed in the 'impulsive' and 'equilibrium' limits, and in a set of intermediate 'evolving' states. The impulsive atmospheres have the density distribution frozen in the pre-flare configuration, while the equilibrium models assume the entire atmosphere is in hydrostatic and energetic equilibrium. The evolving atmospheres represent intermediate stages where hydrostatic equilibrium has been established in the chromosphere and corona, but the corona is not yet in energetic equilibrium with the flare heating source. Thus, for example, chromospheric evaporation is still in the process of occurring. We have computed the chromospheric radiation that results from a range of coronal heating rates, with particular emphasis on the widely observed diagnostic H(alpha). Our conclusion is that the H(alpha) fluxes and profiles actually observed in flares can only be produced under conditions of a low-pressure corona with strong beam heating. Therefore we suggest that H(alpha) in flares is produced primarily at the footprints of newly heated loops where significant evaporation has not yet occurred. As a single loop evolves in time, no matter how strong the heating rate may become, the H(alpha) flux will diminish as the corona becomes denser and hence more effective at stopping the beam. This prediction leads to several observable consequences regarding the spatial and temporal signatures of the X-ray and H(alpha) radiation during flares. Title: EUVE Spectral Observations of a Flare on AD Leonis Authors: Cully, S. L.; Fisher, G. H.; Hawley, S. L.; Simon, T. Bibcode: 1994AAS...184.4507C Altcode: 1994BAAS...26..935C The flare star AD Leo (dM3.5e, 4.9 parsecs) was observed by the EUVE DS/S from 1993 March 1 - March 3 UT. A flare was detected in the Lexan/Boron (65 - 190 Angstroms) band of the Deep Survey Instrument on March 2 UT. The flare was also observed with optical photometry at several locations and with both high and low resolution optical spectroscopy. The 0.3 magnitude optical U band (3000 - 4300 Angstroms) flare had a peak DS Lex/B count rate of about 1.0 cps and was visible for 7 hours. The total EUV energy released in the flare is estimated to be 1 x 10(33) ergs. The above results were given by Hawley et al (1994). In this work, we present the EUVE spectra (70 - 760 Angstroms) for the quiescent and flaring times of the observation and differential emission measure analysis of the strong emission lines visible in each spectrum. Title: Absolute Magnitudes and Kinematics of RR Lyrae Stars via Statistical Parallax Authors: Layden, A. C.; Hanson, R. B.; Hawley, S. L. Bibcode: 1994AAS...184.3202L Altcode: 1994BAAS...26..911L The absolute magnitude of the RR Lyrae stars is integral in determining the distances to the old stellar systems in our Galaxy and to other Local Group galaxies, and in determining the ages of the Galactic globular clusters. We present new estimates of the RR Lyrae star absolute magnitude as a function of metal abundance, based on a new set of statistical parallax solutions. This analysis is an improvement over previous works for several reasons: (1) it relies mainly on new absolute proper motions from the Lick Northern Proper Motion Survey, which are of uniformly high quality. (2) new metal abundances and radial velocities are employed; the former are of particularly high quality and uniformity. (3) the improved metallicities, combined with kinematic analyses, allow us for the first time to properly separate thick--disk and halo stars; these populations must be treated separately for the solutions to be valid, and (4) over 200 stars are used in this analysis (>20% have thick disk kinematics), significantly more than in previous solutions. We discuss the kinematic properties of the local RR Lyrae stars, and briefly discuss our absolute magnitude results with regard to the distances and ages of some RR Lyrae-bearing populations. Title: X-Ray Emission from Halo M Dwarfs Authors: Hawley, Suzanne L.; Feigelson, Eric D. Bibcode: 1994ASPC...64...89H Altcode: 1994csss....8...89H No abstract at ADS Title: Solar flare model atmospheres Authors: Hawley, Suzanne L.; Fisher, George H. Bibcode: 1993STIN...9519034H Altcode: Solar flare model atmospheres computed under the assumption of energetic equilibrium in the chromosphere are presented. The models use a static, one-dimensional plane parallel geometry and are designed within a physically self-consistent coronal loop. Assumed flare heating mechanisms include collisions from a flux of non-thermal electrons and x-ray heating of the chromosphere by the corona. The heating by energetic electrons accounts explicitly for variations of the ionized fraction with depth in the atmosphere. X-ray heating of the chromosphere by the corona incorporates a flare loop geometry by approximating distant portions of the loop with a series of point sources, while treating the loop leg closest to the chromospheric footpoint in the plane-parallel approximation. Coronal flare heating leads to increased heat conduction, chromospheric evaporation and subsequent changes in coronal pressure; these effects are included self-consistently in the models. Cooling in the chromosphere is computed in detail for the important optically thick HI, CaII and MgII transitions using the non-LTE prescription in the program MULTI. Hydrogen ionization rates from x-ray photo-ionization and collisional ionization by non-thermal electrons are included explicitly in the rate equations. The models are computed in the 'impulsive' and 'equilibrium' limits, and in a set of intermediate 'evolving' states. The impulsive atmospheres have the density distribution frozen in pre-flare configuration, while the equilibrium models assume the entire atmosphere is in hydrostatic and energetic equilibrium. The evolving atmospheres represent intermediate stages where hydrostatic equilibrium has been established in the chromosphere and corona, but the corona is not yet in energetic equilibrium with the flare heating source. Thus, for example, chromospheric evaporation is still in the process of occurring. Title: Magnetic Activity in Low-Mass Stars Authors: Hawley, Suzanne L. Bibcode: 1993PASP..105..955H Altcode: The manifestations of magnetic activity in low mass stars, particularly M dwarfs, can be used as a tool to study their evolution, the operation of the interior dynamo with changing interior conditions, and the structure of their outer atmospheres. Extensive background material on the current understanding of low mass stellar activity is presented. Two new surveys are described which will greatly increase the number of active low mass stars known in the field and in nearby open clusters. These surveys will define the characteristics of the activity on low mass stars, and how the activity changes with a number of parameters of interest, including mass, effective temperature, and age. The data will also allow a rigorous determination of a possible age-activity relation among the low mass M dwarfs. Theoretical models of M dwarf atmospheres, and their connection to the understanding of the observations, are also discussed. (SECTION: The Second Hubble Fellows Symposium) Title: Echelle Spectra of the 6 March 1993 Solar Flare Authors: Johns, C. M.; Basri, G. S.; Hawley, S. L. Bibcode: 1993BAAS...25.1189J Altcode: No abstract at ADS Title: Solar Flare Model Atmospheres Authors: Hawley, S. L.; Fisher, G. H. Bibcode: 1993BAAS...25R1190H Altcode: No abstract at ADS Title: Simultaneous Optical and EUVE Observations of a Flare on AD Leo Authors: Hawley, S. L.; Deustua, S. E.; Cully, S. L.; Fisher, G. H.; Johns, C. M.; Simon, T.; Smith, V. V.; Spiesman, W. J. Bibcode: 1993AAS...182.3808H Altcode: 1993BAAS...25..856H An 80,000 second pointed observation of the flare star AD Leo was carried out during 1-3 March 1993 (UT) by EUVE. Concurrent optical monitoring observations were made using three telescopes at Lick Observatory and two telescopes at McDonald Observatory. On 2 March 1993 (UT), the first simultaneous optical and EUV observations of a stellar flare were obtained. The optical data include multi-color photometry, and low and high resolution spectroscopy. We present the data for this flare and compare it to previously observed stellar flares. Title: EUVE Deep Survey Observations of a Flare on AD Leo Authors: Cully, S. L.; Siegmund, O. H. W.; Fisher, G. H.; Johns, C. M.; Hawley, S. L.; Duestra, S.; Simon, T. Bibcode: 1993AAS...182.4104C Altcode: 1993BAAS...25R.860C The flare star AD Leo was observed by the EUVE Deep Survey instrument from 1993 March 1 through March 3 UT. A flare was detected in the Lexan/boron (65-190 Angstroms) band on March 2 UT. This flare was also observed in the optical U band and with both high and low resolution spectroscopy. We compare this flare with solar observations and discuss the implications for EUV stellar flare statistics. This work has been supported by NASA grant NAGW-1290 and NASA contracts NAS5-29298 and -30180. Title: An Initial Search for Low Mass Stars with the 2MASS Prototype Camera Authors: Chester, T.; Beichman, C.; Evans, T.; Kopan, G.; Schombert, J.; Kleinmann, S.; Lysaght, M.; Skrutksie, M.; Armus, L.; Matthews, K.; Neugebauer, G.; Reid, N.; Soifer, T.; Tinney, C.; Hawley, S. L. Bibcode: 1992AAS...181.6809C Altcode: 1992BAAS...24.1229C The Two Micron All Sky Survey (2MASS) is a ground-based, all-sky survey at 1.2, 1.6 and 2.2 microns (J, H and K(') ) to a uniform limiting K(') magnitude of 14 (10 sigma ) for point sources. A prototype camera has been built to test many aspects of the survey. The camera was used to obtain multiple (10) scans of a selected 1 square degree region at intermediate galactic latitude, to investigate the completeness, reliability, and positional accuracy that could be achieved in the survey. Results from the processing of these data, presented here, demonstrate that we currently exceed all the goals in these areas. To understand the classes of sources that were detected, we have compared all detected sources with m_{K('}) < 14 to optical sources extracted from digitized POSS I plates. The infrared sources are highly reliable, having been confirmed on 10 separate repeated scans. The distribution of R - K(') colors is consistent with those expected from normal stellar populations, except for one source with m_{K('}) = 13.1 which has no counterpart on the POSS I. Follow-up observations show that the source is actually double with a separation of about 0.5", with both components having roughly equal magnitudes at I, J, H, K(') , and L(') . Each of the components have the color of M6--7 stars, with a total R magnitude of 18.9, consistent with the combined spectrum. The lack of a detection on the POSS I plates is probably due to the extreme red color of this object, but a high proper motion cannot yet be ruled out. These stars are at an inferred distance of about 30--70 pc. If they represent a binary system, the stars are separated by only 15--35 AU. Since this object was found from a survey of only one square degree, and fewer than 100 stars are known with spectral types later than M5, it is clear that 2MASS will be valuable in deriving a complete census of nearby low-mass stars that is not biased by proper motion selection effects. Title: Magnetic activity in low mass stars Authors: Hawley, S. L. Bibcode: 1992STIN...9328547H Altcode: The manifestations of magnetic activity in low mass stars, particularly M dwarfs, can be used as a tool to study their evolution, the operation of the interior dynamo with changing interior conditions, and the structure of their outer atmospheres. Extensive background material on the current understanding of low mass stellar activity is presented. Two new surveys are described which will greatly increase the number of active low mass stars known in the field and in nearby open clusters. These surveys will define the characteristics of the activity on low mass stars, and how the activity changes with a number of parameters of interest, including mass, effective temperature, and age. The data will also allow a rigorous determination of a possible age-activity relation among the low mass M dwarfs. Theoretical models of M dwarf atmospheres, and their connection to the understanding of the observations, are also discussed. Title: Starspots - the ZEBRA Effect Authors: Pettersen, Bjorn R.; Hawley, Suzanne L.; Fisher, George H. Bibcode: 1992SoPh..142..197P Altcode: Recent observations of brightness variations on the Sun during the solar cycle have motivated us to re-examine the widely held view that cool, dark starspots, covering a significant fraction of the star, are the centers of magnetic activity on BY Dra stars. We propose that the magnetic regions are better described by a bright facular network, and that the dark areas which give rise to photometric rotational modulation are actually regions where the underlying quiet photosphere is seen. This interpretation is consistent with recent observations of late-type stars that show that bright areas covering much of the star have magnetic fields with strengths of several thousand gauss. It resolves several problems with the current model, including the size, location, and stability of the starspots required to match photometric and Doppler-imaging observations. It also has interesting observational implications for the correlation of photometric rotational modulation and long term brightness variations with other surface activity, and for the positions of magnetically active stars in the H-R diagram. Title: New Cepheid Distances to Nearby Galaxies Based on BVRI CCD Photometry. III. NGC 300 Authors: Freedman, Wendy L.; Madore, Barry F.; Hawley, S. L.; Horowitz, Irwin K.; Mould, Jeremy; Navarrete, Mauricio; Sallmen, Shauna Bibcode: 1992ApJ...396...80F Altcode: A true distance modulus of (m - M)_0_ = 26.66 +/- 0.10 mag (corresponding to 2.1 +/- 0.1 Mpc) has been determined for the Sculptor Group spiral galaxy NGC 300. New CCD data have been obtained for a sample of known Cepheids in this galaxy from which apparent distance moduli at B, V, R, and I wavelengths are determined. Combining the data available at different wavelengths, and assuming a true distance modulus to the LMC of 18.5 mag, a true distance modulus is obtained for NGC 300, corrected for the effects of interstellar reddening. The availability of a new distance to NGC 300 brings to five the total number of galaxies with new CCD photometry of Cepheids, useful for calibration of the Hubble constant. Title: X-Ray-heated Models of Stellar Flare Atmospheres: Theory and Comparison with Observations: Erratum Authors: Hawley, Suzanne L.; Fisher, George H. Bibcode: 1992ApJS...81..885H Altcode: No abstract at ADS Title: Solar Flare Model Atmospheres Authors: Fisher, G. H.; Hawley, S. L. Bibcode: 1992AAS...180.4101F Altcode: 1992BAAS...24..794F We present 3 sets of solar flare atmospheric models, computed in 3 different limits. In all of the models, energy balance is assumed, with radiative losses from the optically thick transitions of HI, CaII, and MgII balancing flare heating from nonthermal electrons and X-rays from the flaring corona. In the ``Hydrostatic'' models, we have assumed that flare heating by Coulomb collisions from a flux of nonthermal electrons has been occurring for an infinitely long time, and the corona and chromosphere have achieved both energetic and hydrostatic equilibrium. In the ``Impulsive'' models, we have assumed that the atmospheric density remains frozen in its preflare state, but that the atmosphere rapidly achieves a temperature structure consistent with energy balance. In the ``Evolving'' models, we have assumed a temporal variation of the nonthermal electron heating rate consistent with flare heating for timescales of 5-10 minutes, corresponding to a long lived and intense flare, continually undergoing chromospheric evaporation. In this case, the chromospheric model is in hydrostatic equilibrium, but the flare transition region is at depths that are much less than those in the ``Hydrostatic'' models. We present temperature and density structures in these model atmospheres, line and continuum fluxes from each model, and a few selected line profiles. G.H.F. is supported by AFOSR grant AFOSR-91-116, NASA grant NAGW-2969, and NSF grant ATM91-06052. S.L.H. is supported in part by a Hubble Fellowship from STSI, and in part by Lawrence Livermore National Laboratory. Lawrence Livermore is supported by the US Department of Energy under contract number W-7405-ENG-48. Title: X-Ray--heated Models of Stellar Flare Atmospheres: Theory and Comparison with Observations Authors: Hawley, Suzanne L.; Fisher, George H. Bibcode: 1992ApJS...78..565H Altcode: A sequence of five model atmospheres consisting of the photosphere, chromosphere, and transition region is computed. The models represent the response of the gas in a magnetically confined loop to intense flare energy release. It is concluded that the structure of the flare transition region is consistent with the conductive heating balancing optically thin cooling; some UV line fluxes can be used as a transition-region 'pressure gauge' and can provide a constraint on the flare area. These models predict ratios of Ca II to hydrogen emission which are much greater than those observed; they also predict Balmer line profiles which are much narrower than those observed. It is inferred that additional heating is taking place in the upper chromosphere beyond that assumed in the models. The observed flare continuum is much bluer than that computed from the models; the observations fit a blackbody spectrum with T approximately equal to 8500-9500 K. It is proposed that the flare continuum is formed by photospheric reprocessing of intense UV to the EUV line emission from the upper chromosphere. Title: Energy Balance Models of Solar Flare Atmospheres Authors: Hawley, S. L.; Fisher, G. H. Bibcode: 1992ASPC...26..534H Altcode: 1992csss....7..534H No abstract at ADS Title: A ZEBRA Interpretation of BY DRA Stars Authors: Pettersen, B. R.; Hawley, S. L.; Fisher, G. H. Bibcode: 1992ASPC...26..285P Altcode: 1992csss....7..285P No abstract at ADS Title: The Great Flare of 1985 April 12 on AD Leonis Authors: Hawley, Suzanne L.; Pettersen, Bjorn R. Bibcode: 1991ApJ...378..725H Altcode: A giant flare on the M dwarf star AD Leo is examined on the basis of photometric and spectroscopic observations covering the wavelength range 1200-1800 A. A flare energy budget over the entire optical and ultraviolet wavelength region is constructed as a function of time during the flare. The continuum radiation is shown to be the dominant source of energy loss during both the initial 'impulsive' phase and the later 'gradual' phase. The emission lines contribute less than 10 percent of the total flare energy in this wavelength region but are about four times more important during the gradual phase than in the impulsive phase. The energy budget is compared with another, less energetic, flare on AD Leo and found to be quite similar. The relationships between the integrated properties of several flare emission features are investigated. Good correlation between H-gamma and Ca II K emission, and H-gamma and U filter emission is found. It is inferred from these correlations that the observed emission features are produced under similar atmospheric conditions regardless of the total flare energy emitted. Title: Absolute Magnitudes and Kinematic Properties of Cepheids Authors: Wilson, Teresa D.; Barnes, Thomas G., III; Hawley, Suzanne L.; Jefferys, William H. Bibcode: 1991ApJ...378..708W Altcode: The relative solar motions, Oort constants, velocity ellipsoid parameters, and zero points of the PL and PLC relations are determined by performing a maximum likelihood statistical parallax analysis of classical Cepheids. The analysis is based on 90 proper motions drawn from the list of Karimova and Pavlovskaya (1981) and on the analytical approach of Hawley et al. (1986). The results give a best estimate for the mean absolute magnitude of Cepheids which, for the Cepheid absolute magnitude zero point, is highly stable against refinements in the mathematical technique and against additional Cepheid proper motion data of quality similar to the existing proper motions. The solar motion components along the axes of uncertainties less than + or - 2 km/s are also determined. Title: Absolute Magnitudes and Kinematic Properties of Cepheids Authors: Barnes, T. G., III; Wilson, T. D.; Hawley, S. L.; Jefferys, W. H. Bibcode: 1991BAAS...23Q.877B Altcode: No abstract at ADS Title: What Do Stellar Flares Tell Us About Solar White Light Flares? Authors: Fisher, G. H.; Hawley, S. L. Bibcode: 1991BAAS...23R1067F Altcode: No abstract at ADS Title: The response of the chromosphere during a stellar flare. Authors: Hawley, Suzanne L. Bibcode: 1991MmSAI..62..271H Altcode: A set of chromospheric models was developed, having a coronal loop geometry, energy balance through the entire loop from photosphere to corona, and a rigorous treatment of the radiative transfer in the important, optically thick, chromospheric emission lines. The models show that the soft X-ray emission and thermal conduction from a long lived hot corona are effective heating agents in the lower atmosphere during the gradual phase of stellar flares. The model predictions show the correct order of magnitude for the emission lines produced during the gradual phase of the flare with a reasonable coronal temperature evolution. Title: Absolute magnitudes and kinematic properties of Cepheids. Authors: Wilson, T. D.; Jefferys, W. H.; Barnes, T. G., III; Hawley, S. L. Bibcode: 1991amkp.book.....W Altcode: A maximum-likelihood statistical parallax analysis of classical Cepheids has been performed to determine the relative solar motion, Oort constants, velocity ellipsoid parameters, and zero points of the PL and PLC relations. The analysis is based upon 90 proper motions drawn from the list of Karimova and Pavlovskaya 1981 and upon the analytical approach of Hawley et al. 1986. The authors' results give a best estimate for the mean absolute magnitude of Cepheids at log P = 0.8 of <Mv> = -3.46±0.33 mag. This estimate for the Cepheid absolute magnitude zero point is highly stable against refinements in the mathematical technique and against additional Cepheid proper motion data of quality similar to the existing proper motions. Improvement in this value will likely come only from a marked improvement in the quality of the Cepheid proper motions. Title: Starspots: The Zebra Effect Authors: Pettersen, B. R.; Hawley, S. L. Bibcode: 1990BAAS...22.1202P Altcode: No abstract at ADS Title: The 12 April 1985 Flare on AD Leo Authors: Hawley, S. L.; Pettersen, B. R. Bibcode: 1990BAAS...22.1202H Altcode: No abstract at ADS Title: An Equation for the Evolution of Solar and Stellar Flare Loops Authors: Fisher, George H.; Hawley, Suzanne L. Bibcode: 1990ApJ...357..243F Altcode: An ordinary differential equation describing the evolution of a coronal loop subjected to a spatially uniform but time-varying heating rate is discussed. It is assumed that the duration of heating is long compared to the sound transit time through the loop, which is assumed to have uniform cross section area. The form of the equation changes as the loop evolves through three states: 'strong evaporation', 'scaling law behavior', and 'strong condensation'. Solutions to the equation may be used to compute the time dependence of the average coronal temperature and emission measure for an assumed temporal variation of the flare heating rate. The results computed from the model agree reasonably well with recent published numerical simulations and may be obtained with far less computational effort. The model is then used to study the May 21, 1980, solar flare observed by SMM and the giant April 12, 1985, flare observed on the star AD Leo. Title: The Metallicity Sensitivity of the Cepheid Period-Luminosity Relation: Implications for the Extragalactic Distance Scale Authors: Madore, B. F.; Freedman, W. L.; Hawley, S. L. Bibcode: 1990BAAS...22..841M Altcode: No abstract at ADS Title: An Equation for the Evolution of Solar and Stellar Flare Loops Authors: Hawley, S. L.; Fisher, G. H. Bibcode: 1990BAAS...22..826H Altcode: No abstract at ADS Title: The Flare Activity of the Uv-Ceti System 1966-1988 Authors: Pettersen, B. R.; Sundland, S. R.; Hawley, S. L.; Coleman, L. A. Bibcode: 1990ASPC....9..177P Altcode: 1990csss....6..177P No abstract at ADS Title: The flare activity of the red dwarf binary Gliese 277AB. Authors: Hawley, S. L.; Panov, K. P.; Pettersen, B. R.; Sundland, S. R. Bibcode: 1989A&A...220..218H Altcode: Both red dwarf components of the system Gliese 277 AB show the Ca II HK and H I Balmer lines in emission. Extensive photoelectric monitoring has revealed flare activity in the bright star but not in the faint. Estimates of an upper limit for the flare activity level of the faint star place it among the very inactive dM stars despite its prominent emission lines. The activity level of the bright star is typical for its spectral class. Title: A spectroscopic survey of red dwarf flare stars. Authors: Pettersen, B. R.; Hawley, S. L. Bibcode: 1989A&A...217..187P Altcode: Low resolution CCD spectra of dKe and dMe stars, many of which are active flare stars and spotted stars are presented. Most objects are covered from 3500 A to 7500 A; some have coverage extending to 9000 A. The strength of various chromospheric emission lines and photospheric molecular features is measured, and the run of these quantities with stellar intrinsic brightness is investigated. Title: An Observational and Theoretical Investigation of Stellar Flares. Authors: Hawley, Suzanne Louise Bibcode: 1989PhDT.........1H Altcode: Multi-wavelength observations of a giant flare on the star AD Leo were obtained with the 2.1m and 0.9m telescopes at McDonald Observatory and the International Ultraviolet Explorer satellite. The quality, spectral coverage and time resolution of the data represent a major improvement over any published stellar flare data. A self -consistent theoretical model was developed to investigate the effects of chromospheric heating by thermal conduction and soft x-ray irradiation from a flare heated corona. Assuming a one-dimensional coronal loop geometry, atmospheres were produced for overlying coronal temperatures of 8, 10, 15, and 20 million degrees Kelvin. The atmospheres satisfy the equations of hydrostatic equilibrium, steady state energy balance, and statistical equilibrium and radiative transfer in many optically thick transitions of hydrogen, ionized calcium and ionized magnesium. A second theoretical model was then developed to predict the temporal evolution of the coronal temperature under the influence of a time varying flare heating rate. Combining the models, the chromospheric emission model predictions in the hydrogen Balmer lines, Ca II K, Mg II h + k and the optical continuum were compared to the observations, with the result that much of the gradual phase flare emission could be produced by the x-ray and conductive heated atmospheres. However, some additional heating and a more complex flare geometry, including several emitting regions, are probably required to reproduce all the flare emission features in detail. The models also lend insight into the impulsive phase flare emission, but do not reproduce it. Soft x-ray and conductive heating of the chromosphere is a natural consequence of the coronal temperatures that have been observed during the gradual phase of flares on the sun and on M dwarf stars. The improved flare observations and quantitative flare models presented here show that these heating mechanisms can produce atmospheres whose emission matches many of the observed stellar flare features. Future studies must incorporate these effects as well as considering other heating mechanisms and more complex flare geometries. Title: Independence of chromospheric active and soft X-ray flaring on the flare star EV Lacertae. Authors: Ambruster, C. W.; Pettersen, B. R.; Hawley, S. L.; Coleman, L. A.; Sciortino, S. Bibcode: 1989sasf.confP..27A Altcode: 1988sasf.conf...27A; 1989IAUCo.104P..27A EXOSAT observed the flare star EV Lacertae for 17 hr over 2 days in October 1985. Two flaring episodes were recorded. During a significant fraction of these observations, IUE, photometric and spectroscopic coverage was available. A 2-hour long period of X-ray flaring was observed during which there was no U-band activity and almost no chromospheric activity. On the other hand, two ΔU ≡ 1m5 optical flares produced normal chromospheric enhancements, but only a weak X-ray response. The authors suggest that these and a few other observations of stellar flares may imply the occasional existence of magnetically isolated regions in M-dwarf atmospheres. Title: Stellar flares: observations and theory. Authors: Hawley, S. L. Bibcode: 1989sasf.confP..49H Altcode: 1988sasf.conf...49H; 1989IAUCo.104P..49H Photometric and spectroscopic observations of a very large flare on AD Leo are presented. A self consistent model of a flare corona, transition region and chromosphere is developed; in particular the chromospheric temperature distributions resulting from X-ray and EUV irradiation by coronae of various temperatures are determined. The predicted line fluxes in Hγ are compared to the observed line fluxes to find the coronal temperature as a function of time during the flare. This run of temperature with time is then compared with the predictions of an independent theoretical flare model based on a dynamic scaling law. Title: A dynamic scaling law for solar and stellar flare loops. Authors: Fisher, G. H.; Hawley, S. L. Bibcode: 1989sasf.confP.353F Altcode: 1989IAUCo.104P.353F; 1988sasf.conf..353F The authors discuss an ordinary differential equation which describes how the pressure in a coronal loop may evolve in time under the influence of a uniform, but time varying heating rate. Title: Contemporaneous Photometry and Radial Velocities of RR Lyrae Stars Authors: Barnes, Thomas G., III; Moffett, Thomas J.; Hawley, Suzanne L.; Slovak, Mark H.; Frueh, Marian L. Bibcode: 1988ApJS...67..403B Altcode: Contemporaneous BVRI photometry and radial velocities of seven RR Lyrae variables covering nearly the full span in Delta S and including the RRc star T Sex are reported. Over 3000 BVRI measures at 100 s time resolution and over 400 radial velocity measures are included. The photometric uncertainties are of order + or - 0.007 mag in V, (B - V) and (V - R) and + or - 0.014 in (R - I). The radial velocity uncertainties range from + or - 3.8 to + or - 8.0 km/s, correlated with the metal deficiency. Light, color, and velocity curves are given. Title: V1589 Cyg=B19: A foreground dMe flare star in the direction of NGC 7000 Authors: Pettersen, B. R.; Tsvetkov, M. K.; Hawley, S. L.; Coleman, L. A.; Amirkhanyan, A. S. Bibcode: 1988Ap.....29..445P Altcode: 1989Ap.....29..445P No abstract at ADS Title: Radiation losses in chromospheric and transition region emission lines from AD Leo (dM4e) Authors: Sundland, S. R.; Pettersen, B. R.; Hawley, S. L.; Kjeldseth-Moe, O.; Andersen, B. N. Bibcode: 1988ASSL..143...61S Altcode: 1988acse.conf...61S The authors present line surface fluxes from the red dwarf flare star AD Leo in its quiescent state. IUE and ground-based instruments cover the UV and optical (1000 - 9000 Å) domains of the spectrum. The observed radiation losses from chromospheric and transition region lines amount to 4.0×106erg cm-2s-1 and 2.7×105erg cm-2s-1, respectively. The authors estimate the total radiative energy loss in all lines formed between 25.000K and 250.000K to be of the order of 106 - 107erg cm-2s-1. Title: B-19-A flare star in front of the NGC 7000 aggregate Authors: Tsvetkov, M. K.; Pettersen, B. R.; Hawley, S. L. Bibcode: 1988ASSL..143...77T Altcode: 1988acse.conf...77T No abstract at ADS Title: V1589 Cyg-B19- a foreground dMe flare star in the direction of NGC 7000. Authors: Pettersen, B. R.; Tsvetkov, M. K.; Hawley, S. L.; Coleman, L. A.; Amirkhanian, A. S. Bibcode: 1988Afz....29...67P Altcode: Photographic and photoelectric flare observations of V1589 Cyg show that flare durations from minutes to hours, with amplitudes up to 2 magnitudes in the U-filter, occur. V1589 Cyg is suggested to be a dM4.5e flare star at a distance of 23 - 32 parsecs. Title: Contemporaneous Photometry and Radial Velocities of RR Lyrae Stars Authors: Barnes, T. G., III; Moffett, T. J.; Hawley, S. L.; Slovak, M. H.; Frueh, M. L. Bibcode: 1987BAAS...19.1052B Altcode: No abstract at ADS Title: Surface Brightness Analysis of RR Lyrae Stars Authors: Hawley, S. L.; Barnes, T. G., III; Hindsley, R. G.; Moffett, T. J. Bibcode: 1987BAAS...19Q1053H Altcode: No abstract at ADS Title: Discovery of flare activity on BD +3 4138B. Authors: Pettersen, B. R.; Hawley, S. L. Bibcode: 1987A&A...181..402P Altcode: A Cassegrain spectrograph spectrum has been obtained for BD + 3 deg 4138 B. The wavelength-calibrated spectrum subsequently derived shows a typical M dwarf profile with numerous atomic lines and molecular features. H-beta, H-gamma, and H-delta appear in emission, and the spectrum is noted to be a close match for the flare star Gliese 494 in both chromospheric and photospheric features. Title: The Cepheid Surface-Brightness Relation and the Slope of the P-L Relation Authors: Barnes, T. G.; Moffett, T. J.; Jefferys, W. H.; Hawley, S. L. Bibcode: 1987BAAS...19..754B Altcode: No abstract at ADS Title: A Surface Brightness Analysis of Eight RR Lyrae Stars Authors: Hawley, Suzanne L.; Barnes, Thomas G.; Moffett, Thomas J. Bibcode: 1987LNP...274..235H Altcode: 1987stpu.conf..235H We have used a surface brightness, (V-R) relation to analyze new contemporaneous photometry and radial velocity data for 6 RR-ab type stars and to re-analyze previously published data for RR Lyrae and X Arietis. Systematic effects were found in the surface brightness at phases near minimum radius. Excluding these phases, we determine the slope of the surface brightness relation and the mean radius for each star. We also find a zero point which includes both a distance term and the zero point of the surface brightness relation. Title: An episode of mass expulsion from the M-dwarf flare star EV Latertae ? Authors: Ambruster, C. W.; Pettersen, B. R.; Hawley, S.; Coleman, L. A.; Sandmann, W. H. Bibcode: 1986ESASP.263..137A Altcode: 1986NIA86......137A; 1986niia.conf..137A In October 1985, observations of the M-dwarf flare star EV Lacertae were conducted for nine consecutive days with IUE, along with contemporaneous ground-based photometric and spectrophotometric coverage, and two extended pointings by EXOSAT to search for atmospheric anomalies which might help to explain the unusually violent flaring behavior of this star. On the night of 8 October 1985 all measured UV fluxes dropped by a factor 2 for 1.5 hr, apparently the result of a major episode of mass expulsion. The simultaneous Ca K (lambda 3934) and H beta light curves imply that a significant flare took place shortly before the start of the IUE observations on this night. No rotational modulation of the light curve was detected, and the mean Mg II (lamdba 2800) and C IV (lamdba 1550) fluxes are very similar to the values for YZ CMi, from which no superflares are reported. Title: Optical and UV observations of a giant stellar flare on AD Leo Authors: Pettersen, B. R.; Hawley, S. L.; Andersen, B. N. Bibcode: 1986ESASP.263..157P Altcode: 1986NIA86......157P; 1986niia.conf..157P A giant stellar flare has been observed on the dM4e star AD Leo simultaneously with IUE and ground-based instrumentation. The authors present and discuss observations obtained in a 15 minutes interval around flare maximum. A continuum flux distribution of flare light is obtained, based on a SWP spectrum and UBVR photometry corrected for the influence of emission lines. A high temperature (107K) free-free distribution describes the optical data well, but the observed ultraviolet flux is at least one order of magnitude smaller. No single radiation process describes the time averaged flux distribution. Line broadening is evident in hydrogen Balmer emission lines. The Inglis-Teller formula implies an upper limit of 6×1013cm-3 for the electron density. Title: Periodic variability of AD Leo and GL 490A. Authors: Spiesman, W. J.; Hawley, S. L. Bibcode: 1986AJ.....92..664S Altcode: BVRI photometric observations of AD Leo and Gl 490A, obtained using a two-star photometer on the 24-inch telescope at Table Mountain Observatory during March-April 1981 are reported. V and R light curves are presented for each star, and the periods and m(v) amplitudes of the variations are given as 2.7 + or - 0.05 d and 0.024 + or - 0.002 mag for AD Leo and 3.3 + or - 0.05 d and 0.072 + or - 0.002 mag for Gl 490A. Title: On the Absolute Magnitudes of RR Lyrae Stars Authors: Barnes, T. G., III; Hawley, S. L. Bibcode: 1986ApJ...307L...9B Altcode: The photometric data base used by Hawley and colleagues in 1986 to determine a mean absolute magnitude for RR Lyrae stars has been examined for systematic errors. Both the magnitudes published by Fitch et al. in 1966 and Clube and Dawe in 1980 for RR Lyrae stars are shown to differ systematically from intensity mean magnitudes. On the basis of new photometry, better relations are determined for inferring intensity mean magnitudes from partial light curves, using both the Fitch et al. and Clube and Dawe methods. In addition, it is shown that the Fitch et al. photometry requires magnitude-dependent corrections. After correcting the data base for the above effects, the statistical analysis was repeated to determine the mean absolute magnitude for 142 RRab stars with the result +0.68 + or - 0.14 mag. This is 0.08 mag brighter than the previous determination by Hawley et al. Title: Absolute Magnitudes and Kinematic Properties of RR Lyrae Stars Authors: Hawley, S. L.; Jefferys, W. H.; Barnes, T. G., III; Lai, W. Bibcode: 1986ApJ...302..626H Altcode: A maximum-likelihood statistical analysis of several subgroups of the field RR Lyrae stars was performed to determine the relative solar motion, velocity ellipsoid parameters, and mean absolute visual magnitude for each group. The full sample of 159 stars was taken from a recent Chinese proper-motion survey, and new mean radial velocities were used for 46 of the stars. A geometric minimization technique known as simplex optimization was used to apply a rigorous maximum-likelihood model to the data. The best estimate for the mean absolute visual magnitude is 0.76 + or - 0.14 mag for the entire RR ab-type sample. Title: Radial velocities of RR Lyrae stars. Authors: Hawley, S. L.; Barnes, T. G., III Bibcode: 1985PASP...97..551H Altcode: The authors obtained 283 spectra of 57 RR Lyrae stars using the 2.1-m telescope at McDonald Observatory. Radial velocities were determined using a software cross-correlation technique. New mean radial velocities were determined for 46 of the stars. Title: A Maximum Likelihood Investigation of RR Lyrae Kinematics and Absolute Magnitudes Authors: Hawley, S. L.; Barnes, T. G., III; Jefferys, W. H. Bibcode: 1984BAAS...16S.966H Altcode: No abstract at ADS