Author name code: hall
ADS astronomy entries on 2022-09-14
author:"Hall, Jeffrey C."
------------------------------------------------------------------------
Title: Snowmass 2021 Scintillating Bubble Chambers: Liquid-noble
Bubble Chambers for Dark Matter and CE$\nu$NS Detection
Authors: Alfonso-Pita, E.; Baker, M.; Behnke, E.; Bressler, M.;
Broerman, B.; Clark, K.; Corbett, J.; Cripe, C.; Crisler, M.; Dahl,
C. E.; Dering, K.; de St. Croix, A.; Durnford, D.; Foy, K.; Giampa,
P.; Hall, J.; Harris, O.; Hawley-Herrera, H.; Jackson, C. M.; Ko,
Y.; Lamb, N.; Laurin, M.; Levine, I.; Lippincott, W. H.; Liu, X.;
Neilson, R.; Pal, S.; Piro, M. -C.; Priya, S.; Sheng, Z.; Sloss, A.;
Struyk, X.; Vázquez-Jáuregui, E.; Westerdale, S.; Whitis, T. J.;
Zha, W.; Zhang, R.
Bibcode: 2022arXiv220712400A
Altcode:
The Scintillating Bubble Chamber (SBC) Collaboration is developing
liquid-noble bubble chambers for the quasi-background-free detection of
low-mass (GeV-scale) dark matter and coherent scattering (CE$\nu$NS)
of low-energy (MeV-scale) neutrinos. The first physics-scale
demonstrator of this technique, a 10-kg liquid argon bubble chamber
dubbed SBC-LAr10, is now being commissioned at Fermilab. This device
will calibrate the background discrimination power and sensitivity of
superheated argon to nuclear recoils at energies down to 100 eV. A
second functionally-identical detector with a focus on radiopure
construction is being built for SBC's first dark matter search at
SNOLAB. The projected spin-independent sensitivity of this search
is approximately $10^{-43}$ cm$^2$ at 1 GeV$/c^2$ dark matter
particle mass. The scalability and background discrimination power
of the liquid-noble bubble chamber make this technique a compelling
candidate for future dark matter searches to the solar neutrino fog at
1 GeV$/c^2$ particle mass (requiring a $\sim$ton-year exposure with
non-neutrino backgrounds sub-dominant to the solar CE$\nu$NS signal)
and for high-statistics CE$\nu$NS studies at nuclear reactors.
Title: Ionization yield measurement in a germanium CDMSlite detector
using photo-neutron sources
Authors: Albakry, M. F.; Alkhatib, I.; Amaral, D. W. P.; Aralis,
T.; Aramaki, T.; Arnquist, I. J.; Ataee Langroudy, I.; Azadbakht,
E.; Banik, S.; Bathurst, C.; Bauer, D. A.; Bezerra, L. V. S.;
Bhattacharyya, R.; Bowles, M. A.; Brink, P. L.; Bunker, R.; Cabrera,
B.; Calkins, R.; Cameron, R. A.; Cartaro, C.; Cerdeño, D. G.; Chang,
Y. -Y.; Chaudhuri, M.; Chen, R.; Chott, N.; Cooley, J.; Coombes, H.;
Corbett, J.; Cushman, P.; De Brienne, F.; di Vacri, M. L.; Diamond,
M. D.; Fascione, E.; Figueroa-Feliciano, E.; Fink, C. W.; Fouts, K.;
Fritts, M.; Gerbier, G.; Germond, R.; Ghaith, M.; Golwala, S. R.;
Hall, J.; Hines, B. A.; Hollister, M. I.; Hong, Z.; Hoppe, E. W.;
Hsu, L.; Huber, M. E.; Iyer, V.; Jastram, A.; Kashyap, V. K. S.;
Kelsey, M. H.; Kubik, A.; Kurinsky, N. A.; Lawrence, R. E.; Lee,
M.; Li, A.; Liu, J.; Liu, Y.; Loer, B.; Lukens, P.; MacDonell, D.;
MacFarlane, D. B.; Mahapatra, R.; Mandic, V.; Mast, N.; Mayer, A. J.;
Meyer zu Theenhausen, H.; Michaud, É.; Michielin, E.; Mirabolfathi,
N.; Mohanty, B.; Morales Mendoza, J. D.; Nagorny, S.; Nelson, J.;
Neog, H.; Novati, V.; Orrell, J. L.; Osborne, M. D.; Oser, S. M.;
Page, W. A.; Partridge, R.; Pedreros, D. S.; Podviianiuk, R.; Ponce,
F.; Poudel, S.; Pradeep, A.; Pyle, M.; Rau, W.; Reid, E.; Ren, R.;
Reynolds, T.; Roberts, A.; Robinson, A. E.; Saab, T.; Sadoulet, B.;
Saikia, I.; Sander, J.; Sattari, A.; Scarff, A.; Schmidt, B.; Schnee,
R. W.; Scorza, S.; Serfass, B.; Sincavage, D. J.; Stanford, C.; Street,
J.; Thasrawala, F. K.; Toback, D.; Underwood, R.; Verma, S.; Villano,
A. N.; von Krosigk, B.; Watkins, S. L.; Wen, O.; Williams, Z.; Wilson,
M. J.; Winchell, J.; Wykoff, K.; Yellin, S.; Young, B. A.; Yu, T. C.;
Zatschler, B.; Zatschler, S.; Zaytsev, A.; Zhang, E.; Zheng, L.;
Zuber, S.
Bibcode: 2022PhRvD.105l2002A
Altcode: 2022arXiv220207043S
Two photo-neutron sources, 88Y 9Be and
124Sb 9Be, have been used to investigate the
ionization yield of nuclear recoils in the CDMSlite germanium detectors
by the SuperCDMS collaboration. This work evaluates the yield for
nuclear recoil energies between 1 and 7 keV at a temperature of ∼ 50
mK . We use a GEANT4 simulation to model the neutron spectrum assuming
a charge yield model that is a generalization of the standard Lindhard
model and consists of two energy dependent parameters. We perform
a likelihood analysis using the simulated neutron spectrum, modeled
background, and experimental data to obtain the best fit values of the
yield model. The ionization yield between recoil energies of 1 and 7
keV is shown to be significantly lower than predicted by the standard
Lindhard model for germanium. There is a general lack of agreement among
different experiments using a variety of techniques studying the low
energy range of the nuclear recoil yield, which is most critical for
interpretation of direct dark matter searches. This suggests complexity
in the physical process that many direct detection experiments use to
model their primary signal detection mechanism and highlights the need
for further studies to clarify underlying systematic effects that have
not been well understood up to this point.
Title: Effective Field Theory Analysis of CDMSlite Run 2 Data
Authors: SuperCDMS Collaboration; Albakry, M. F.; Alkhatib, I.; Amaral,
D. W. P.; Aralis, T.; Aramaki, T.; Arnquist, I. J.; Ataee Langroudy,
I.; Azadbakht, E.; Banik, S.; Bathurst, C.; Bauer, D. A.; Bezerra,
L. V. S.; Bhattacharyya, R.; Brink, P. L.; Bunker, R.; Cabrera, B.;
Calkins, R.; Cameron, R. A.; Cartaro, C.; Cerdeño, D. G.; Chang,
Y. -Y.; Chaudhuri, M.; Chen, R.; Chott, N.; Cooley, J.; Coombes,
H.; Corbett, J.; Cushman, P.; De Brienne, F.; Dharani, S.; di Vacri,
M. L.; Diamond, M. D.; Fascione, E.; Figueroa-Feliciano, E.; Fink,
C. W.; Fouts, K.; Fritts, M.; Gerbier, G.; Germond, R.; Ghaith,
M.; Golwala, S. R.; Hall, J.; Hassan, N.; Hines, B. A.; Hollister,
M. I.; Hong, Z.; Hoppe, E. W.; Hsu, L.; Huber, M. E.; Iyer, V.;
Jastram, A.; Kashyap, V. K. S.; Kelsey, M. H.; Kubik, A.; Kurinsky,
N. A.; Lawrence, R. E.; Lee, M.; Li, A.; Liu, J.; Liu, Y.; Loer, B.;
Lukens, P.; MacFarlane, D. B.; Mahapatra, R.; Mandic, V.; Mast, N.;
Mayer, A. J.; Theenhausen, H. Meyer zu; Michaud, É.; Michielin, E.;
Mirabolfathi, N.; Mohanty, B.; Nagorny, S.; Nelson, J.; Neog, H.;
Novati, V.; Orrell, J. L.; Osborne, M. D.; Oser, S. M.; Page, W. A.;
Partridge, R.; Pedreros, D. S.; Podviianiuk, R.; Ponce, F.; Poudel,
S.; Pradeep, A.; Pyle, M.; Rau, W.; Reid, E.; Ren, R.; Reynolds,
T.; Roberts, A.; Robinson, A. E.; Rogers, H. E.; Saab, T.; Sadoulet,
B.; Saikia, I.; Sander, J.; Sattari, A.; Schmidt, B.; Schnee, R. W.;
Scorza, S.; Serfass, B.; Poudel, S. S.; Sincavage, D. J.; Stanford,
C.; Street, J.; Sun, H.; Thasrawala, F. K.; Toback, D.; Underwood,
R.; Verma, S.; Villano, A. N.; von Krosigk, B.; Watkins, S. L.; Wen,
O.; Williams, Z.; Wilson, M. J.; Winchell, J.; Wykoff, K.; Yellin,
S.; Young, B. A.; Yu, T. C.; Zatschler, B.; Zatschler, S.; Zaytsev,
A.; Zhang, E.; Zheng, L.; Zuber, S.
Bibcode: 2022arXiv220511683S
Altcode:
CDMSlite Run 2 was a search for weakly interacting massive particles
(WIMPs) with a cryogenic 600 g Ge detector operated in a high-voltage
mode to optimize sensitivity to WIMPs of relatively low mass from 2 -
20 GeV/$c^2$. In this article, we present an effective field theory
(EFT) analysis of the CDMSlite Run 2 data using an extended energy
range and a comprehensive treatment of the expected background. A
binned likelihood Bayesian analysis was performed on the recoil energy
data, taking into account the parameters of the EFT interactions and
optimizing the data selection with respect to the dominant background
components. Energy regions within 5$\sigma$ of known activation peaks
were removed from the analysis. The Bayesian evidences resulting from
the different operator hypotheses show that the CDMSlite Run 2 data are
consistent with the background-only models and do not allow for a signal
interpretation assuming any additional EFT interaction. Consequently,
upper limits on the WIMP mass and coupling-coefficient amplitudes
and phases are presented for each EFT operator. These limits improve
previous CDMSlite Run 2 bounds for WIMP masses above 5 GeV/$c^2$.
Title: Investigating the sources of low-energy events in a
SuperCDMS-HVeV detector
Authors: SuperCDMS Collaboration; Albakry, M. F.; Alkhatib, I.;
Amaral, D. W. P.; Aralis, T.; Aramaki, T.; Arnquist, I. J.; Ataee
Langroudy, I.; Azadbakht, E.; Banik, S.; Bathurst, C.; Bauer,
D. A.; Bhattacharyya, R.; Brink, P. L.; Bunker, R.; Cabrera, B.;
Calkins, R.; Cameron, R. A.; Cartaro, C.; Cerdeño, D. G.; Chang,
Y. -Y.; Chaudhuri, M.; Chen, R.; Chott, N.; Cooley, J.; Coombes,
H.; Corbett, J.; Cushman, P.; De Brienne, F.; Dharani, S.; di Vacri,
M. L.; Diamond, M. D.; Fascione, E.; Figueroa-Feliciano, E.; Fink,
C. W.; Fouts, K.; Fritts, M.; Gerbier, G.; Germond, R.; Ghaith, M.;
Golwala, S. R.; Hall, J.; Hassan, N.; Hines, B. A.; Hollister, M. I.;
Hong, Z.; Hoppe, E. W.; Hsu, L.; Huber, M. E.; Iyer, V.; Jastram,
A.; Kashyap, V. K. S.; Kelsey, M. H.; Kubik, A.; Kurinsky, N. A.;
Lawrence, R. E.; Lee, M.; Li, A.; Liu, J.; Liu, Y.; Loer, B.; Lopez
Asamar, E.; Lukens, P.; MacFarlane, D. B.; Mahapatra, R.; Mandic,
V.; Mast, N.; Mayer, A. J.; Theenhausen, H. Meyer zu; Michaud, É.;
Michielin, E.; Mirabolfathi, N.; Mohanty, B.; Nagorny, S.; Nelson,
J.; Neog, H.; Novati, V.; Orrell, J. L.; Osborne, M. D.; Oser, S. M.;
Page, W. A.; Partridge, R.; Pedreros, D. S.; Podviianiuk, R.; Ponce,
F.; Poudel, S.; Pradeep, A.; Pyle, M.; Rau, W.; Reid, E.; Ren, R.;
Reynolds, T.; Roberts, A.; Robinson, A. E.; Saab, T.; Sadoulet, B.;
Saikia, I.; Sander, J.; Sattari, A.; Schmidt, B.; Schnee, R. W.;
Scorza, S.; Serfass, B.; Poudel, S. S.; Sincavage, D. J.; Stanford,
C.; Street, J.; Sun, H.; Thasrawala, F. K.; Toback, D.; Underwood,
R.; Verma, S.; Villano, A. N.; von Krosigk, B.; Watkins, S. L.; Wen,
O.; Williams, Z.; Wilson, M. J.; Winchell, J.; Wykoff, K.; Yellin,
S.; Young, B. A.; Yu, T. C.; Zatschler, B.; Zatschler, S.; Zaytsev,
A.; Zhang, E.; Zheng, L.; Zuber, S.
Bibcode: 2022arXiv220408038S
Altcode:
Recent experiments searching for sub-GeV/$c^2$ dark matter have observed
event excesses close to their respective energy thresholds. Although
specific to the individual technologies, the measured excess event
rates have been consistently reported at or below event energies of a
few-hundred eV, or with charges of a few electron-hole pairs. In the
present work, we operated a 1-gram silicon SuperCDMS-HVeV detector at
three voltages across the crystal (0 V, 60 V and 100 V). The 0 V data
show an excess of events in the tens of eV region. Despite this event
excess, we demonstrate the ability to set a competitive exclusion limit
on the spin-independent dark matter--nucleon elastic scattering cross
section for dark matter masses of $\mathcal{O}(100)$ MeV/$c^2$, enabled
by operation of the detector at 0 V potential and achievement of a very
low $\mathcal{O}(10)$ eV threshold for nuclear recoils. Comparing the
data acquired at 0 V, 60 V and 100 V potentials across the crystal,
we investigated possible sources of the unexpected events observed
at low energy. The data indicate that the dominant contribution to
the excess is consistent with a hypothesized luminescence from the
printed circuit boards used in the detector holder.
Title: Composition and Density Stratification Observed by SuperCam
in the First 300 Sols in Jezero Crater
Authors: Wiens, R. C.; Udry, A.; Mangold, N.; Beyssac, O.; Quantin,
C.; Sautter, V.; Cousin, A.; Brown, A.; Bosak, T.; Mandon, L.;
Forni, O.; Johnson, J. R.; McLennan, S.; Legett, C.; Maurice, S.;
Mayhew, L.; Anderson, R. B.; Clegg, S. M.; Ollila, A. M.; Hall, J.;
Meslin, P. -Y.; Kah, L. C.; Gabriel, T. S. J.; Gasda, P.; Simon,
J. I.; Hausrath, E. M.; Horgan, B.; Poulet, F.; Beck, P.; Gupta,
S.; Chide, B.; Clavé, E.; Connell, S.; Dehouck, E.; Dromart, G.;
Fouchet, T.; Royer, C.; Frydenvang, J.; Gasnault, O.; Gibbons, E.;
Kalucha, H.; Lanza, N.; Lasue, J.; Le Mouélic, S.; Leveille, R.;
Cloutis, E.; Lopez Reyes, G.; Arana, G.; Castro, K.; Madariaga, J. M.;
Manrique, J. -A.; Pilorget, C.; Pinet, P.; Laserna, J.; Sharma, S. K.;
Acosta-Maeda, T.; Kelly, E.; Crumpler, L.; Montmessin, F.; Fischer,
W.; Francis, R.; Stack, K.; Farley, K.; SuperCam Team
Bibcode: 2022LPICo2678.2075W
Altcode:
Exploration to date shows three compositional regions with the
stratigraphically lower 2 enriched in olivine (Séitah) and pyroxene
(Artuby ridge), respectively.
Title: Geology of the Latmikaik and Xcacau Coronae in the Henie
(V-58) Quadrangle, Venus
Authors: Shackman, J.; Boggs, K. J. E.; Ernst, R. E.; Bethell,
E. M.; Wehnes, H. G. D.; Varg, E.; Pendleton, C.; Jans, W.; Hall,
J.; Dietrich, R. C.; Dhami, L.; Demorcy, J.; Dear, B.; Chowdhury,
M.; Bley, H. N.; Becerra De Rosales, M.
Bibcode: 2022LPICo2678.2693S
Altcode:
This abstract examines the topography of the Latmikaik and Xcacau
Coronae and their relationship with graben swarms and the Tellervo
Chasma.
Title: What is the Extent of the Influence of the Artemis Corona
Across the Henie (V-58) Quadrangle, Southern Venus?
Authors: Bley, H. N.; Boggs, K. J. E.; Ernst, R. E.; Bethell, E. M.;
Becerra De Rosales, M.; Beckie, B.; Chowdhury, M.; Dear, B.; Demorcy,
J.; Dhami, L.; Dietrich, R. C.; Hall, J.; Jans, W.; Pendleton, C.;
Shackman, J.; Varg, E.; Wehnes, H. G. D.
Bibcode: 2022LPICo2678.1765B
Altcode:
We examine the influence of the Artemis system across the Henie
Quadrangle to assess whether the Artemis system is the largest in the
solar system.
Title: A Strategy for Low-Mass Dark Matter Searches with Cryogenic
Detectors in the SuperCDMS SNOLAB Facility
Authors: SuperCDMS Collaboration; Albakry, M. F.; Alkhatib, I.;
Amaral, D. W. P.; Aralis, T.; Aramaki, T.; Arnquist, I. J.; Ataee
Langroudy, I.; Azadbakht, E.; Banik, S.; Bathurst, C.; Bauer,
D. A.; Bhattacharyya, R.; Brink, P. L.; Bunker, R.; Cabrera, B.;
Calkins, R.; Cameron, R. A.; Cartaro, C.; Cerdeno, D. G.; Chang,
Y. -Y.; Chaudhuri, M.; Chen, R.; Chott, N.; Cooley, J.; Coombes, H.;
Corbett, J.; Cushman, P.; De Brienne, F.; Dharani, S.; di Vacri, M. L.;
Diamond, M. D.; Fascione, E.; Figueroa-Feliciano, E.; Fink, C. W.;
Fouts, K.; Fritts, M.; Gerbier, G.; Germond, R.; Ghaith, M.; Golwala,
S. R.; Hall, J.; Hassan, N.; Hines, B. A.; Hollister, M. I.; Hong, Z.;
Hoppe, E. W.; Hsu, L.; Huber, M. E.; Iyer, V.; Jastram, A.; Kashyap,
V. K. S.; Kelsey, M. H.; Kubik, A.; Kurinsky, N. A.; Lawrence, R. E.;
Lee, M.; Li, A.; Liu, J.; Liu, Y.; Loer, B.; Lukens, P.; MacFarlane,
D. B.; Mahapatra, R.; Mandic, V.; Mast, N.; Mayer, A. J.; Theenhausen,
H. Meyer zu; Michaud, E.; Michielin, E.; Mirabolfathi, N.; Mohanty,
B.; Nagorny, S.; Nelson, J.; Neog, H.; Novati, V.; Orrell, J. L.;
Osborne, M. D.; Oser, S. M.; Page, W. A.; Partridge, R.; Pedreros,
D. S.; Podviianiuk, R.; Ponce, F.; Poudel, S.; Pradeep, A.; Pyle,
M.; Rau, W.; Reid, E.; Ren, R.; Reynolds, T.; Roberts, A.; Robinson,
A. E.; Saab, T.; Sadoulet, B.; Saikia, I.; Sander, J.; Sattari, A.;
Schmidt, B.; Schnee, R. W.; Scorza, S.; Serfass, B.; Poudel, S. S.;
Sincavage, D. J.; Stanford, C.; Street, J.; Sun, H.; Thasrawala, F. K.;
Toback, D.; Underwood, R.; Verma, S.; Villano, A. N.; von Krosigk,
B.; Watkins, S. L.; Wen, O.; Williams, Z.; Wilson, M. J.; Winchell,
J.; Wyko, K.; Yellin, S.; Young, B. A.; Yu, T. C.; Zatschler, B.;
Zatschler, S.; Zaytsev, A.; Zhang, E.; Zheng, L.; Zuber, S.
Bibcode: 2022arXiv220308463S
Altcode:
The SuperCDMS Collaboration is currently building SuperCDMS SNOLAB,
a dark matter search focused on nucleon-coupled dark matter in the 1-5
GeV mass range. Looking to the future, the Collaboration has developed a
set of experience-based upgrade scenarios, as well as novel directions,
to extend the search for dark matter using the SuperCDMS technology
in the SNOLAB facility. The experienced-based scenarios are forecasted
to probe many square decades of unexplored dark matter parameter space
below 5 GeV, covering over 6 decades in mass: 1-100 eV for dark photons
and axion-like particles, 1-100 MeV for dark-photon-coupled light
dark matter, and 0.05-5 GeV for nucleon-coupled dark matter. They will
reach the neutrino fog in the 0.5-5 GeV mass range and test a variety
of benchmark models and sharp targets. The novel directions involve
greater departures from current SuperCDMS technology but promise even
greater reach in the long run, and their development must begin now for
them to be available in a timely fashion. The experienced-based upgrade
scenarios rely mainly on dramatic improvements in detector performance
based on demonstrated scaling laws and reasonable extrapolations
of current performance. Importantly, these improvements in detector
performance obviate significant reductions in background levels beyond
current expectations for the SuperCDMS SNOLAB experiment. Given that the
dominant limiting backgrounds for SuperCDMS SNOLAB are cosmogenically
created radioisotopes in the detectors, likely amenable only to isotopic
purification and an underground detector life-cycle from before crystal
growth to detector testing, the potential cost and time savings are
enormous and the necessary improvements much easier to prototype.
Title: Time evolution of magnetic activity cycles in young suns:
The curious case of κ Ceti
Authors: Boro Saikia, S.; Lüftinger, T.; Folsom, C. P.; Antonova,
A.; Alecian, E.; Donati, J. -F.; Guedel, M.; Hall, J. C.; Jeffers,
S. V.; Kochukhov, O.; Marsden, S. C.; Metodieva, Y. T.; Mittag, M.;
Morin, J.; Perdelwitz, V.; Petit, P.; Schmid, M.; Vidotto, A. A.
Bibcode: 2022A&A...658A..16B
Altcode: 2021arXiv211006000B
Context. A detailed investigation of the magnetic properties of young
Sun-like stars can provide valuable information on our Sun's magnetic
past and its impact on the early Earth.
Aims: We determine the
properties of the moderately rotating young Sun-like star κ Ceti's
magnetic and activity cycles using 50 yr of chromospheric activity data
and six epochs of spectropolarimetric observations.
Methods:
The chromospheric activity was determined by measuring the flux in
the Ca II H and K lines. A generalised Lomb-Scargle periodogram and
a wavelet decomposition were used on the chromospheric activity data
to establish the associated periodicities. The vector magnetic field
of the star was reconstructed using the technique of Zeeman Doppler
imaging on the spectropolarimetric observations.
Results:
Our period analysis algorithms detect a 3.1 yr chromospheric cycle in
addition to the star's well-known ~6 yr cycle period. Although the two
cycle periods have an approximate 1:2 ratio, they exhibit an unusual
temporal evolution. Additionally, the spectropolarimetric data analysis
shows polarity reversals of the star's large-scale magnetic field,
suggesting a ~10 yr magnetic or Hale cycle.
Conclusions: The
unusual evolution of the star's chromospheric cycles and their lack
of a direct correlation with the magnetic cycle establishes κ Ceti
as a curious young Sun. Such complex evolution of magnetic activity
could be synonymous with moderately active young Suns, which is an
evolutionary path that our own Sun could have taken.
Title: Analysis of Coronal Mass Ejections Observed by Multiple
Spacecraft, including by WISPR on Parker Solar Probe
Authors: Liewer, Paulett; Hall, Jeffrey; Braga, Carlos; Hess, Phillip;
Penteado, Paulo; Stenborg, Guillermo; Vourlidas, Angelos; Qiu, Jiong
Bibcode: 2021AGUFMSH15A2019L
Altcode:
The Wide-field Imager for Solar Probe (WISPR) has provided high
resolution images of multiple coronal mass ejections (CMEs) during
its first seven encounters with the Sun and most of these have been
observed by white-light instruments on either STEREO A or SOHO or
both. The multiple viewpoints have been important in determining the
source of the CMEs and their trajectories. Here we present results
from the analysis of the origin and trajectories of several WISPR
CMEs with some unexpected results. WISPR has a wide fixed angular
field-of-view (FOV), extending radially from 13.5° to 108° from
the Sun and approximately 50° in the transverse direction, but the
physical extent of the imaged coronal region varies directly with the
distance of the spacecraft from the Sun. We have developed tools for
determining the trajectories of solar ejecta which take into account
the rapid spacecraft motion. We have also developed tools to relate and
compare the CMEs seen in the WISPR images to simultaneous observation
from the other white light telescope (SOHO/LASCO or STEREO/SECCHI),
making uses of the World Coordinate System information in the images
FITS headers. This software allows us to project the trajectory
determined from WISPR or features seen in the WISPR images onto images
from the second white light telescope (or visa versa) to verify the
trajectory determined from the WISPR data alone or to determine a CMEs
location by triangulation. Utilizing the multiple viewpoints has led
to a better understanding of the structure and evolution of the CMEs.
Title: Satellite Constellation Issues Need Science Communicators
Authors: Hall, J.; Walker, C.; Krafton, K.
Bibcode: 2021ASPC..531..148H
Altcode:
Future large constellations of bright satellites in low-Earth
orbit (LEOsats) will fundamentally change observational astronomy
at optical wavelengths. Nighttime images without satellite trails
will no longer be the norm. If the 100,000+ LEOsats proposed are
deployed, no combination of mitigations can fully avoid the impacts
of satellite trails on science programs of current and planned
ground-based optical astronomical facilities. Astrophotography,
amateur astronomy, and the human experience of a starry night sky
are already affected. The report from the Satellite Constellations 1
(SATCON1) workshop (29 June-2 July 2020), as well as the report from
the Dark and Quiet Skies for Science and Society (D&QS) workshop
(October 5-9 2020), support these statements. The aim of SATCON1 and the
Satellite Constellation Working Group of D&QS was to better quantify
the impacts of LEOsat constellations, explore possible mitigations,
and make recommendations.
Mitigation strategies for the most
damaging impacts on scientific programs are being actively explored
by astronomers worldwide. These investigations have benefited from
collaboration with SpaceX, the first operator to launch satellite
constellations. SpaceX has shown that operators can reduce reflected
sunlight through satellite orientation, Sun shielding, and surface
darkening. A joint effort to obtain higher accuracy public data
on predicted locations of satellites (or ephemerides) could enable
some pointing avoidance and mid-exposure shuttering during satellite
passage. Observatories need to adopt more dynamic scheduling and
observation management as the number of constellation satellites
increases, though these measures may prove ineffective for many science
programs. To successfully implement these next steps, more buy-in
is needed from our astronomy community and the general public. What
if our community of science educators and communicators could create
awareness of the issues and possible mitigations? Come to our session
to learn more.
Title: SATCON2: Observations Working Group Report
Authors: Rawls, Meredith L.; Barron, Darcy; Birdwell, Ian; Cirkovic,
Elena; Deck, Tim; Di Vruno, Federico; Gokhale, Vayujeet; Goodman,
Matthew; Kafka, Stella; Kebe, Fatoumata; Knox, Doug; Krantz, Harrison;
Kruk, Sandor; Lawler, Samantha; Monet, Dave; Peel, Mike; Tregloan-Reed,
Jeremy; Zamora, Olga; Allen, Lori; Walker, Connie; Hall, Jeffrey
Bibcode: 2021zndo...5608826R
Altcode:
No abstract at ADS
Title: SATCON2: Policy Working Group Report
Authors: Green, Richard; Allen, Lori; Andrade, Bohnlein, Jurgen; Boley,
Aaron; Cooper, Patricia; Dunn, Mat; Falle, Andrew; Grunsfeld, John;
Hanlon, Michelle; Hartley, Ruskin; Hofer, Chris; Jakhu, Jansson, Gerry;
Jones, Therese; Knox, Doug; Krafton, Kelsie; Liszt, Harvey; Mishra,
Nishith; Mudd, Charles; Parriott, Joel; Rosenberg, Erica; Puxley,
Phil; Raval, Vikram; Rotola, Giuliana; Sedwick, Ray; Simon-Butler,
Andrew; Smith, Joshua; Vanotti, Maurizio; Walker, Connie; Williams,
Andrew; Walker, Constance; Hall, Jeffrey
Bibcode: 2021zndo...5609224G
Altcode:
The charge to the SATCON2 Policy Working Group was to review existing
national policies and legislative frameworks. With the SATCON1
recommendations as context, the group was charged to assess policy
options to serve the diverse requirements of astronomy, the satellite
industry, and other communities.
Title: SATCON2: Algorithms Working Group Report
Authors: McDowell, Jonathan; Seaman, Rob; Bassa, Cees;
Galadí-Enríquez, David; Hainaut, Olivier; Hodgson, Courtney; Holman,
Matt; Jah, Moriba; Kavelaars, JJ. Poletti, Keith; Schmitz, Morgan;
Seitzer, Pat; Siminski, Jan; Street, Rachel; Teimoorinia, Hossen;
Thiemann, Heidi; Walker, Connie; Walker, Constance; Hall, Jeffrey
Bibcode: 2021zndo...5608843M
Altcode:
No abstract at ADS
Title: SATCON2: Community Engagement Working Group Report
Authors: Venkatesan, Aparna; Lowenthal, James; Arion, Doug; Avila
Castro, Fernando; Bannister, Michele; Barentine, John; Begay, David;
Chavez, Juan-Carlos; Carttar, Sally; Gering, Rick; Hartley, Ruskin;
Hall, Jeffrey; Harvey, Alvin; Heim, Jessica; Kafka, Stella; Kimura,
Ka'iu; Larsen, Kris; Lee, Annette; Maryboy, Nancy; Neilson, Hilding;
Nesvold, Erika; Simons, Doug; Sweitzer, James; Umpierre, Diana;
Walker, Connie; Wakker, Constance Walker
Bibcode: 2021zndo...5608920V
Altcode:
No abstract at ADS
Title: SATCON2: Executive Summary
Authors: Hall, Jeffrey; Walker, Constance; Rawls, Meredith; McDowell,
Jonathan; Seaman, Robert; Venkatesan, Aparna; Lowenthal, James; Green,
Richard; Krafton, Kelsie; Parriott, Joel
Bibcode: 2021BAAS...53b0205H
Altcode:
No abstract at ADS
Title: The Sun as a young star: reproducing the X-ray cycle of ɛ
Eridani with solar magnetic structures
Authors: Coffaro, M.; Stelzer, B.; Orlando, S.; Hall, J.; Metcalfe,
T. S.; Wolter, U.; Mittag, M.; Sanz-Forcada, J.; Ducci, L.
Bibcode: 2021csss.confE..38C
Altcode:
Epsilon Eri is a young solar-like star with a ~3 yr X-ray activity
cycle, detected by us for the first time in a dedicated XMM-Newton
long-term monitoring campaign. The magnetic structures on the Sun
are intimately linked to the 11-yr activity cycle and they were
spatially and temporally resolved throughout the solar cycle. However,
for other stars these structures can not be spatially resolved
with present-day X-ray instruments. We have, thus, developed a new
technique which allows us to reproduce the stellar X-ray variability
in terms of time-variations in the coverage of the corona with the
same kind of magnetic structures observed on the Sun: active regions
(ARs), cores of active regions (COs) and flares (FLs). This poster
presents this new method and the results we obtained for the case of
Epsilon Eri. Our approach is to simulate a grid of emission measure
distributions (EMDs) derived from the analysis of regions observed
in the solar corona to artificially reproduce a solar-like corona
with the physical characteristics of Epsilon Eri. The three magnetic
structures are allowed to contribute to the total coronal EMD with
varying area coverage fraction. Thus, from a comparison between these
pseudo-solar EMDs and the observations of Epsilon Eri, we are able to
associate to each state of the X-ray activity cycle of Epsilon Eri the
percentage of ARs, COs and FLs on the corona of the star. The observed
amplitude of the X-ray luminosity in the cycle of Epsilon Eri is much
smaller than on the Sun. Our analysis provides a physical explanation
for this: the simulated EMDs indicate that in all phases of the X-ray
cycle a large portion of the corona of Epsilon Eri is covered by active
structures. Therefore, there is little space for adding further magnetic
structures in the cycle maximum. In the future, this method will be
applied to other stars providing an important contribution to better
understand the solar-stellar corona connection.
Title: Color Properties at the Mars InSight Landing Site
Authors: Maki, J. N.; Golombek, M.; Banerdt, W.; Smrekar, S.; Deen,
R.; Abarca, H.; Lu, S.; Hall, J.
Bibcode: 2021E&SS....801336M
Altcode:
The color properties observed at the InSight landing site by the
lander cameras are spectral mixtures of two source materials: gray
black rocky material with chromaticity values of x = 0.32, y = 0.32
(standard deviations of σx = 0.02 and σy =
0.03) and yellowish brown dust with chromaticity values of x = 0.42, y =
0.36 (standard deviations of σx = 0.02 and σy
= 0.03). These results are consistent with published values from other
Mars landed missions. The InSight measurements also include the first
published value of the white point of Mars daylight, chromaticity of
x = 0.35, y = 0.34 (standard deviations of σx = 0.01 and
σy = 0.02), which is redder than earth daylight by δx =
0.04 and δy = 0.01. InSight measurements also show a small color
difference (δx = 0.02 and δy = 0.01) between the near field terrain
(within 20 m of the lander) and the far field area beyond. This color
difference is believed to be caused by dust being blown off by near
field terrain by the lander rockets during the landing event. The
visual difference between these two regions is caused primarily by
the brightness variation. Chromaticity measurements of the Martian
sky also match previous missions with additional variability caused
by differences in dust loading and the dynamic nature of the Martian
atmosphere.
Title: Scientific goals for the Venus Flagship Mission's aerobot
Authors: Wilson, C. F.; Gilmore, M. S.; Beauchamp, P. M.; Atreya,
S. K.; Baines, K.; Goolish, E.; Bullock, M.; Curry, S.; Hall, J.;
Izraelevitz, J.; Jackson, J. M.; Nikolic, D.
Bibcode: 2020AGUFMP050...03W
Altcode:
The Venus Flagship Mission (VFM), a Decadal mission concept study,
includes a variable altitude balloon operating at altitudes from 52 km
(where p = 0.8 bar, T = 60°C) to 62 km (p = 0.16 bar, T = -20°C). This
range allows study both of the convective cloud, found at altitudes
< 60 km, and of the convectively stable upper cloud at > 60
km. This range also includes the 20-40°C "habitable zone" of Venus'
clouds, one of the most benign environments known beyond Earth. The
aerobot's payload is focused in three areas: composition, meteorology,
and geophysics. For composition, the key instrument is an aerosol mass
spectrometer with nephelometer. It measures both gas composition and
aerosol/cloud composition, using dedicated inlets for each. Astrobiology
is addressed by a dedicated fluorimetric microscope, which will examine
cloud droplets for minute traces of constituents associated with past
or present life. Meteorological sensors include air pressure &
temperature sensors, radiometer, 3-D anemometer and a radiation
dosimeter. Finally, the aerobot carries payloads addressing the
geophysics of the solid planet below. An infrasound sensor will search
for acoustic waves triggered by tectonic and volcanic activity. Magnetic
field measurements will search for remnant crustal magnetism, constrain
core size and properties from magnetic field draping, and search for
E-M signatures of lightning. A visible imager, taking images of the
balloon and Venus cloudscapes, completes the payload.
Title: Venus Drill and Sample Delivery System
Authors: Zacny, K.; Hall, J.
Bibcode: 2020LPICo2356.8022Z
Altcode:
We present development and testing of Venus drill and sample delivery
system.
Title: Venus Corona and Tessera Explore (VeCaTEx) Mission Concept:
Investigatin the Surface of Venus from Beneath the Clouds
Authors: Cutts, J.; Baines, K.; Beauchamp, P.; Bower, C.; Dais, A.;
Dorsky, L.; Dyar, D.; Fesq, L.; Freeman, A.; Ghail, R.; Gilmore, M.;
Grimm, R.; Gulcher, A.; Head, J.; Helbert, J.; Jackson, J.; De Jong,
M.; Hall, J.; Izraelevitz, J.; Krishnamoorthy, S.; Matthies, L.;
Montesi, L.; Pauken, M.; Senske, D.; Sotin, C.; Sutin, B.; Wilson, C.
Bibcode: 2020LPICo2356.8031C
Altcode:
VeCaTEx would use an aerobot to descend repeatedly beneath the dense
clouds for imaging targeted area of the surface in the near infrared
spectral region to address six of the prime investigations prioritized
by VEXAG.
Title: New-Frontiers Class Venus In-Situ Exploration: The Venus
Climate and Geophysics Mission (VCGM) Concept
Authors: Baines, K. H.; Cutts, J. A.; Dorsky, L.; Hall, J.; Akins, A.;
Davis, A.; Komjathy, A.; Krishnamoorthy, S.; Nikolic, D.; Vergados,
P.; Akins, A.; Atreya, S.; Bullock, M.; Hunter, G.; Lebonnois, S.;
Lognonne, P.; Mousis, O.; O'Rourke, J.; Renard, J. -B.; Wilson, C.
Bibcode: 2020LPICo2356.8005B
Altcode:
A class of prolonged global-scale, in-situ Venus New Frontiers missions
is described. Via an instrumented variable-altitude balloon supported
by a science/comm orbiter and probes, the mission class satisfies >
80% of VEXAG GOI investigations.
Title: Dark & Quiet Skies I (2020)
Authors: Walker, Connie; Di Pippo, Simona; Aubé, Martin; Barentine,
John; Benkhaldoun, Zouhair; Benvenuti, Piero; Bouroussis, Costis;
Green, Richard; Hearnshaw, John; Mackenzie, Aoraki; Liszt, Harvey;
Lowenthal, James D.; Muñoz-Tuñón, Casiana; Nield, Kathryn; Ricard,
Nathalie; Rodriguez Espinosa, Jose Miguel; Sanhueza, Pedro; Varela
Pérez, Antonia M.; Williams, Andrew; Lau, Steve; Muñoz Tuñón,
Casiana; Rodríguez Espinosa, José M.; Muñoz-Tuñon, Casiana;
Armas, Juan Pablo; Benn, Chris; Blattner, Peter; Diaz-Castro,
Javier; Donners, Maurice; Douglas, Bryan; Gašparovský, Dionýz;
Hall, Jeffrey; Kolláth, Zoltán; Novak, Tomas; Ortolani, Sergio;
Rodríguez Espinosa, José Miguel; Lowenthal, James; Bara, Salvador;
Jägerbrand, Annika; Jechow, Andreas; Longcore, Travis; Motta, Mario;
Schlangen, Luc; Schroer, Sibylle; Lucatello, Sara; Galadí-Enríquez,
David; Micheva, Genoveva; Otarola, Angel; Allen, Lori; Bannister,
Michelle; Barstow, Martin; Bassa, Cees; Davies, Roger; Devost,
Daniel; Hainaut, Olivier; Jah, Moriba; Krafton, Kelsie; Krantz, Harry;
Kucharski, Daniel; Maclay, Timothy; Massey, Robert; Mudd, Charles, Jr.;
McDowell, Jonathan; Parriott, Joel; Pearce, Eric; Rawls, Meredith;
Rotola, Giuliana; Seaman, Rob; Seitzer, Patrick; Siminski, Jan;
Storrie-Lombardi, Lisa; Street, Rachel; Tregloan-Reed, Jeremy; Tyson,
J. Anthony; Unda-Sanzana, Eduardo; Wainscoat, Richard; Zamora, Olga
Bibcode: 2020dqs1.rept.....W
Altcode:
Upon request from the United Nations Committee on the Peaceful Uses
of Outer Space (COPUOS), the UN Office of Outer Space Affairs, the
International Astronomical Union and Spain are organising a Conference
on "Dark and Quiet Skies for Science and Society", postponed to April
2021 [n.b. subsequently postponed to October 2021] due to the Covid-19
pandemic. An online Workshop took place from 5 to 9 October 2020 to
discuss initial findings and draft recommendations. The present report
is the outcome from this Workshop; the recommendations it contains
will be reviewed during the forthcoming Conference with the aim to be
presented to the COPUOS Meeting in June 2021. The purpose and
scope of the Conference and Workshop is to propose to COPUOS a set
of recommendations, to be acted upon either by local governments or
agreed to at an international level, aimed at protecting the science
of astronomy. (It is not intended to include these recommendations
into wider Space Treaties, their scope being solely confined to the
protection of the science of astronomy.)
Title: Velocity independent constraints on spin-dependent DM-nucleon
interactions from IceCube and PICO
Authors: Aartsen, M. G.; Ackermann, M.; Adams, J.; Aguilar, J. A.;
Ahlers, M.; Ahrens, M.; Alispach, C.; Andeen, K.; Anderson, T.;
Ansseau, I.; Anton, G.; Argüelles, C.; Auffenberg, J.; Axani, S.;
Backes, P.; Bagherpour, H.; Bai, X.; Balagopal V., A.; Barbano, A.;
Barwick, S. W.; Bastian, B.; Baum, V.; Baur, S.; Bay, R.; Beatty,
J. J.; Becker, K. -H.; Becker Tjus, J.; BenZvi, S.; Berley, D.;
Bernardini, E.; Besson, D. Z.; Binder, G.; Bindig, D.; Blaufuss, E.;
Blot, S.; Bohm, C.; Börner, M.; Böser, S.; Botner, O.; Böttcher,
J.; Bourbeau, E.; Bourbeau, J.; Bradascio, F.; Braun, J.; Bron, S.;
Brostean-Kaiser, J.; Burgman, A.; Buscher, J.; Busse, R. S.; Carver,
T.; Chen, C.; Cheung, E.; Chirkin, D.; Choi, S.; Classen, L.; Coleman,
A.; Collin, G. H.; Conrad, J. M.; Coppin, P.; Correa, P.; Cowen, D. F.;
Cross, R.; Dave, P.; De Clercq, C.; DeLaunay, J. J.; Dembinski, H.;
Deoskar, K.; De Ridder, S.; Desiati, P.; de Vries, K. D.; de Wasseige,
G.; de With, M.; DeYoung, T.; Diaz, A.; Díaz-Vélez, J. C.; Dujmovic,
H.; Dunkman, M.; Dvorak, E.; Eberhardt, B.; Ehrhardt, T.; Eller,
P.; Engel, R.; Evenson, P. A.; Fahey, S.; Fazely, A. R.; Felde, J.;
Filimonov, K.; Finley, C.; Franckowiak, A.; Friedman, E.; Fritz, A.;
Gaisser, T. K.; Gallagher, J.; Ganster, E.; Garrappa, S.; Gerhardt, L.;
Ghorbani, K.; Glauch, T.; Glüsenkamp, T.; Goldschmidt, A.; Gonzalez,
J. G.; Grant, D.; Griffith, Z.; Griswold, S.; Günder, M.; Gündüz,
M.; Haack, C.; Hallgren, A.; Halve, L.; Halzen, F.; Hanson, K.; Haungs,
A.; Hebecker, D.; Heereman, D.; Heix, P.; Helbing, K.; Hellauer, R.;
Henningsen, F.; Hickford, S.; Hignight, J.; Hill, G. C.; Hoffman,
K. D.; Hoffmann, R.; Hoinka, T.; Hokanson-Fasig, B.; Hoshina, K.;
Huang, F.; Huber, M.; Huber, T.; Hultqvist, K.; Hünnefeld, M.;
Hussain, R.; In, S.; Iovine, N.; Ishihara, A.; Japaridze, G. S.;
Jeong, M.; Jero, K.; Jones, B. J. P.; Jonske, F.; Joppe, R.; Kang,
D.; Kang, W.; Kappes, A.; Kappesser, D.; Karg, T.; Karl, M.; Karle,
A.; Katz, U.; Kauer, M.; Kelley, J. L.; Kheirandish, A.; Kim, J.;
Kintscher, T.; Kiryluk, J.; Kittler, T.; Klein, S. R.; Koirala, R.;
Kolanoski, H.; Köpke, L.; Kopper, C.; Kopper, S.; Koskinen, D. J.;
Kowalski, M.; Krings, K.; Krückl, G.; Kulacz, N.; Kurahashi, N.;
Kyriacou, A.; Labare, M.; Lanfranchi, J. L.; Larson, M. J.; Lauber,
F.; Lazar, J. P.; Leonard, K.; Leszczynska, A.; Leuermann, M.; Liu,
Q. R.; Lohfink, E.; Lozano Mariscal, C. J.; Lu, L.; Lucarelli, F.;
Lünemann, J.; Luszczak, W.; Lyu, Y.; Ma, W. Y.; Madsen, J.; Maggi,
G.; Mahn, K. B. M.; Makino, Y.; Mallik, P.; Mallot, K.; Mancina, S.;
Mariş, I. C.; Maruyama, R.; Mase, K.; Maunu, R.; McNally, F.; Meagher,
K.; Medici, M.; Medina, A.; Meier, M.; Meighen-Berger, S.; Menne, T.;
Merino, G.; Meures, T.; Micallef, J.; Momenté, G.; Montaruli, T.;
Moore, R. W.; Morse, R.; Moulai, M.; Muth, P.; Nagai, R.; Naumann, U.;
Neer, G.; Niederhausen, H.; Nowicki, S. C.; Nygren, D. R.; Pollmann,
A. Obertacke; Oehler, M.; Olivas, A.; O'Murchadha, A.; O'Sullivan,
E.; Palczewski, T.; Pandya, H.; Pankova, D. V.; Park, N.; Peiffer,
P.; Pérez de los Heros, C.; Philippen, S.; Pieloth, D.; Pinat, E.;
Pizzuto, A.; Plum, M.; Porcelli, A.; Price, P. B.; Przybylski, G. T.;
Raab, C.; Raissi, A.; Rameez, M.; Rauch, L.; Rawlins, K.; Rea, I. C.;
Reimann, R.; Relethford, B.; Renschler, M.; Renzi, G.; Resconi, E.;
Rhode, W.; Richman, M.; Robertson, S.; Rongen, M.; Rott, C.; Ruhe,
T.; Ryckbosch, D.; Rysewyk, D.; Safa, I.; Sanchez Herrera, S. E.;
Sandrock, A.; Sandroos, J.; Santander, M.; Sarkar, S.; Sarkar, S.;
Satalecka, K.; Schaufel, M.; Schieler, H.; Schlunder, P.; Schmidt,
T.; Schneider, A.; Schneider, J.; Schröder, F. G.; Schumacher,
L.; Sclafani, S.; Seckel, D.; Seunarine, S.; Shefali, S.; Silva,
M.; Snihur, R.; Soedingrekso, J.; Soldin, D.; Song, M.; Spiczak,
G. M.; Spiering, C.; Stachurska, J.; Stamatikos, M.; Stanev, T.;
Stein, R.; Steinmüller, P.; Stettner, J.; Steuer, A.; Stezelberger,
T.; Stokstad, R. G.; Stössl, A.; Strotjohann, N. L.; Stürwald, T.;
Stuttard, T.; Sullivan, G. W.; Taboada, I.; Tenholt, F.; Ter-Antonyan,
S.; Terliuk, A.; Tilav, S.; Tomankova, L.; Tönnis, C.; Toscano, S.;
Tosi, D.; Trettin, A.; Tselengidou, M.; Tung, C. F.; Turcati, A.;
Turcotte, R.; Turley, C. F.; Ty, B.; Unger, E.; Unland Elorrieta,
M. A.; Usner, M.; Vandenbroucke, J.; Van Driessche, W.; van Eijk, D.;
van Eijndhoven, N.; Vanheule, S.; van Santen, J.; Vraeghe, M.; Walck,
C.; Wallace, A.; Wallraff, M.; Wandkowsky, N.; Watson, T. B.; Weaver,
C.; Weindl, A.; Weiss, M. J.; Weldert, J.; Wendt, C.; Werthebach, J.;
Whelan, B. J.; Whitehorn, N.; Wiebe, K.; Wiebusch, C. H.; Wille, L.;
Williams, D. R.; Wills, L.; Wolf, M.; Wood, J.; Wood, T. R.; Woschnagg,
K.; Wrede, G.; Xu, D. L.; Xu, X. W.; Xu, Y.; Yanez, J. P.; Yodh, G.;
Yoshida, S.; Yuan, T.; Zöcklein, M.; IceCube Collaboration; Amole,
C.; Ardid, M.; Arnquist, I. J.; Asner, D. M.; Baxter, D.; Behnke,
E.; Bressler, M.; Broerman, B.; Cao, G.; Chen, C. J.; Chowdhury, U.;
Clark, K.; Collar, J. I.; Cooper, P. S.; Crisler, M.; Crowder, G.;
Cruz-Venegas, N. A.; Dahl, C. E.; Das, M.; Fallows, S.; Farine, J.;
Felis, I.; Filgas, R.; Girard, F.; Giroux, G.; Hall, J.; Hardy, C.;
Harris, O.; Hoppe, E. W.; Jin, M.; Klopfenstein, L.; Krauss, C. B.;
Laurin, M.; Lawson, I.; Leblanc, A.; Levine, I.; Lippincott, W. H.;
Mamedov, F.; Maurya, D.; Mitra, P.; Moore, C.; Nania, T.; Neilson,
R.; Noble, A. J.; Oedekerk, P.; Ortega, A.; Piro, M. -C.; Plante,
A.; Podviyanuk, R.; Priya, S.; Robinson, A. E.; Sahoo, S.; Scallon,
O.; Seth, S.; Sonnenschein, A.; Starinski, N.; Štekl, I.; Sullivan,
T.; Tardif, F.; Vázquez-Jáuregui, E.; Walkowski, N.; Wichoski, U.;
Yan, Y.; Zacek, V.; Zhang, J.; PICO Collaboration
Bibcode: 2020EPJC...80..819A
Altcode: 2019arXiv190712509I
Adopting the Standard Halo Model (SHM) of an isotropic Maxwellian
velocity distribution for dark matter (DM) particles in the Galaxy,
the most stringent current constraints on their spin-dependent
scattering cross-section with nucleons come from the IceCube neutrino
observatory and the PICO-60 C3F8 superheated
bubble chamber experiments. The former is sensitive to high energy
neutrinos from the self-annihilation of DM particles captured in
the Sun, while the latter looks for nuclear recoil events from
DM scattering off nucleons. Although slower DM particles are more
likely to be captured by the Sun, the faster ones are more likely to
be detected by PICO. Recent N-body simulations suggest significant
deviations from the SHM for the smooth halo component of the DM,
while observations hint at a dominant fraction of the local DM being
in substructures. We use the method of Ferrer et al. (JCAP 1509: 052,
2015) to exploit the complementarity between the two approaches and
derive conservative constraints on DM-nucleon scattering. Our results
constrain σSD≲3 ×10-39cm2 (6
×10-38cm2 ) at ≳90 % C.L. for a DM particle
of mass 1 TeV annihilating into τ+τ- (b b ¯ )
with a local density of ρDM=0.3 GeV/cm 3 . The
constraints scale inversely with ρDM and are independent
of the DM velocity distribution.
Title: Impact of Satellite Constellations on Optical Astronomy and
Recommendations Toward Mitigations
Authors: Walker, Constance; Hall, Jeffrey; Allen, Lori; Green,
Richard; Seitzer, Patrick; Tyson, Tony; Bauer, Amanda; Krafton,
Kelsie; Lowenthal, James; Parriott, Joel; Puxley, Phil; Abbott,
Tim; Bakos, Gaspar; Barentine, John; Bassa, Cees; Blakeslee, John;
Bradshaw, Andrew; Cooke, Jeff; Devost, Daniel; Galadí-Enríquez,
David; Haase, Flynn; Hainaut, Olivier; Heathcote, Steve; Jah, Moriba;
Krantz, Harrison; Kucharski, Daniel; McDowell, Jonathan; Mróz,
Przemek; Otarola, Angel; Pearce, Eric; Rawls, Meredith; Saunders,
Clare; Seaman, Rob; Siminski, Jan; Snyder, Adam; Storrie-Lombardi,
Lisa; Tregloan-Reed, Jeremy; Wainscoat, Richard; Williams, Andrew;
Yoachim, Peter
Bibcode: 2020BAAS...52.0206W
Altcode: 2020BAAS...52b0206W
In May 2019 SpaceX launched its first batch of 60 Starlink communication
satellites, which surprised astronomers and laypeople with their
appearance in the night sky. Astronomers have only now, a little
over a year later, accumulated enough observations of constellation
satellites like those being launched by SpaceX and OneWeb, and run
computer simulations of their likely impact when fully deployed, to
thoroughly understand the magnitude and complexity of the problem. This
research informed the discussion at the Satellite Constellations 1
(SATCON1) workshop held virtually 29 June to 2 July 2020 and led to
recommendations for observatories and constellation operators. The
SATCON1 report concludes that the effects on astronomical research
and on the human experience of the night sky range from "negligible"
to "extreme."
Title: An X-ray activity cycle on the young solar-like star ɛ Eridani
Authors: Coffaro, M.; Stelzer, B.; Orlando, S.; Hall, J.; Metcalfe,
T. S.; Wolter, U.; Mittag, M.; Sanz-Forcada, J.; Schneider, P. C.;
Ducci, L.
Bibcode: 2020A&A...636A..49C
Altcode: 2020arXiv200211009C
Chromospheric Ca II activity cycles are frequently found in late-type
stars, but no systematic programs have been created to search for
their coronal X-ray counterparts. The typical time scale of Ca II
activity cycles ranges from years to decades. Therefore, long-lasting
missions are needed to detect the coronal counterparts. The XMM-Newton
satellite has so far detected X-ray cycles in five stars. A particularly
intriguing question is at what age (and at what activity level) X-ray
cycles set in. To this end, in 2015 we started the X-ray monitoring
of the young solar-like star ɛ Eridani, previously observed on two
occasions: in 2003 and in early 2015, both by XMM-Newton. With an age
of 440 Myr, it is one of the youngest solar-like stars with a known
chromospheric Ca II cycle. We collected the most recent Mount Wilson
S-index data available for ɛ Eridani, starting from 2002, including
previously unpublished data. We found that the Ca II cycle lasts 2.92 ±
0.02 yr, in agreement with past results. From the long-term XMM-Newton
lightcurve, we find clear and systematic X-ray variability of our
target, consistent with the chromospheric Ca II cycle. The average
X-ray luminosity is 2 × 1028erg s-1, with an
amplitude that is only a factor of 2 throughout the cycle. We apply a
new method to describe the evolution of the coronal emission measure
distribution of ɛ Eridani in terms of solar magnetic structures:
active regions, cores of active regions, and flares covering the
stellar surface at varying filling fractions. Combinations of these
three types of magnetic structures can only describe the observed
X-ray emission measure of ɛ Eridani if the solar flare emission
measure distribution is restricted to events in the decay phase. The
interpretation is that flares in the corona of ɛ Eridani last longer
than their solar counterparts. We ascribe this to the lower metallicity
of ɛ Eridani. Our analysis also revealed that the X-ray cycle of ɛ
Eridani is strongly dominated by cores of active regions. The coverage
fraction of cores throughout the cycle changes by the same factor as
the X-ray luminosity. The maxima of the cycle are characterized by a
high percentage of covering fraction of the flares, consistent with
the fact that flaring events are seen in the corresponding short-term
X-ray lightcurves predominately at the cycle maxima. The high X-ray
emission throughout the cycle of ɛ Eridani is thus explained by the
high percentage of magnetic structures on its surface.
Title: Geology of the InSight landing site on Mars
Authors: Golombek, M.; Warner, N. H.; Grant, J. A.; Hauber, E.; Ansan,
V.; Weitz, C. M.; Williams, N.; Charalambous, C.; Wilson, S. A.;
DeMott, A.; Kopp, M.; Lethcoe-Wilson, H.; Berger, L.; Hausmann, R.;
Marteau, E.; Vrettos, C.; Trussell, A.; Folkner, W.; Le Maistre, S.;
Mueller, N.; Grott, M.; Spohn, T.; Piqueux, S.; Millour, E.; Forget,
F.; Daubar, I.; Murdoch, N.; Lognonné, P.; Perrin, C.; Rodriguez, S.;
Pike, W. T.; Parker, T.; Maki, J.; Abarca, H.; Deen, R.; Hall, J.;
Andres, P.; Ruoff, N.; Calef, F.; Smrekar, S.; Baker, M. M.; Banks,
M.; Spiga, A.; Banfield, D.; Garvin, J.; Newman, C. E.; Banerdt, W. B.
Bibcode: 2020NatCo..11.1014G
Altcode:
The Interior Exploration using Seismic Investigations, Geodesy and Heat
Transport (InSight) spacecraft landed successfully on Mars and imaged
the surface to characterize the surficial geology. Here we report on
the geology and subsurface structure of the landing site to aid in
situ geophysical investigations. InSight landed in a degraded impact
crater in Elysium Planitia on a smooth sandy, granule- and pebble-rich
surface with few rocks. Superposed impact craters are common and eolian
bedforms are sparse. During landing, pulsed retrorockets modified the
surface to reveal a near surface stratigraphy of surficial dust, over
thin unconsolidated sand, underlain by a variable thickness duricrust,
with poorly sorted, unconsolidated sand with rocks beneath. Impact,
eolian, and mass wasting processes have dominantly modified the
surface. Surface observations are consistent with expectations made
from remote sensing data prior to landing indicating a surface composed
of an impact-fragmented regolith overlying basaltic lava flows.
Title: The SNOLAB underground laboratory
Authors: Hall, J.
Bibcode: 2020JPhCS1468a2252H
Altcode:
The SNOLAB laboratory is 2 kilometers undeground in Sudbury,
Ontario, Canada. The depth of this location results in a reduction of
cosmic-radiation induced muons to the negligible level of one muon per
square meter per day. The laboratory maintains cleanliness standards
to control the radioactivity from dust falling out of the air, from
human activity, and from research equipment brought into the lab. The
resulting low-radiation environment enables a variety of research, and
SNOLAB is focused on rare-event searches such as dark matter searches
and nuclear decay studies. In order to enable and advance these research
topics, SNOLAB is conducting research and development into cleanliness,
low-level assay, radioactive gasses and cryogenics. SNOLAB collaborates,
and competes, with other underground laboratories on these research
and development topics, as well as operational topics, to support the
global research community.
Title: Flagstaff's Dark Sky Heritage
Authors: Hall, J.
Bibcode: 2020AAS...23518106H
Altcode:
Flagstaff, Arizona has a 60-year tradition of dark sky preservation,
beginning with a 1958 ordinance to ban advertising searchlights. The
current ordinance, enacted in 1989, is the most comprehensive in
the world; it specifies not only shielding and maximum illumination
requirements, but strict control of the emission spectrum via use
of low pressure sodium (LPS) lamps. As of the end of May 2019, LPS
lamps have been discontinued by lighting manufacturers, so Flagstaff,
like many cities worldwide, will be switching its outdoor street
lighting system to LEDs. We have spent several years working with
City staff to develop what will again be world-leading standards in
outdoor illumination, making extensive use of narrow band amber (NBA)
and phosphor-converted amber (PCA) LEDs rather than white LEDs. We
have already installed NBA and PCA test fixtures in several areas
around town, and retrofit of all 3,700 fixtures in Flagstaff should
occur in the next 2-5 years. These standards will set the precedent
for other applications such as commercial properties and parking lots
(pictured below). In this iPoster, I will review the history of dark
sky preservation in Flagstaff, the current state of affairs in outdoor
lighting, the types of LEDs available, their impact on the night sky,
and how Flagstaff will preserve its exceptionally dark sky in the
LED era.
Title: Data-driven modeling of electron recoil nucleation in PICO
C3F8 bubble chambers
Authors: Amole, C.; Ardid, M.; Arnquist, I. J.; Asner, D. M.; Baxter,
D.; Behnke, E.; Bressler, M.; Broerman, B.; Cao, G.; Chen, C. J.;
Chen, S.; Chowdhury, U.; Clark, K.; Collar, J. I.; Cooper, P. S.;
Coutu, C. B.; Cowles, C.; Crisler, M.; Crowder, G.; Cruz-Venegas,
N. A.; Dahl, C. E.; Das, M.; Fallows, S.; Farine, J.; Filgas, R.;
Fuentes, J.; Girard, F.; Giroux, G.; Hackett, B.; Hagen, A.; Hall,
J.; Hardy, C.; Harris, O.; Hillier, T.; Hoppe, E. W.; Jackson, C. M.;
Jin, M.; Klopfenstein, L.; Kozynets, T.; Krauss, C. B.; Laurin, M.;
Lawson, I.; Leblanc, A.; Levine, I.; Licciardi, C.; Lippincott,
W. H.; Loer, B.; Mamedov, F.; Mitra, P.; Moore, C.; Nania, T.;
Neilson, R.; Noble, A. J.; Oedekerk, P.; Ortega, A.; Pal, S.; Piro,
M. -C.; Plante, A.; Priya, S.; Robinson, A. E.; Sahoo, S.; Scallon,
O.; Seth, S.; Sonnenschein, A.; Starinski, N.; Štekl, I.; Sullivan,
T.; Tardif, F.; Tiwari, D.; Vázquez-Jáuregui, E.; Wagner, J. M.;
Walkowski, N.; Weima, E.; Wichoski, U.; Wierman, K.; Woodley, W.;
Yan, Y.; Zacek, V.; Zhang, J.; PICO Collaboration
Bibcode: 2019PhRvD.100h2006A
Altcode: 2019arXiv190512522A
The primary advantage of moderately superheated bubble chamber detectors
is their simultaneous sensitivity to nuclear recoils from weakly
interacting massive particle (WIMP) dark matter and insensitivity to
electron recoil backgrounds. A comprehensive analysis of PICO gamma
calibration data demonstrates for the first time that electron recoils
in C3F8 scale in accordance with a new nucleation
mechanism, rather than one driven by a hot spike as previously
supposed. Using this semiempirical model, bubble chamber nucleation
thresholds may be tuned to be sensitive to lower energy nuclear recoils
while maintaining excellent electron recoil rejection. The PICO-40L
detector will exploit this model to achieve thermodynamic thresholds
as low as 2.8 keV while being dominated by single-scatter events from
coherent elastic neutrino-nucleus scattering of solar neutrinos. In
one year of operation, PICO-40L can improve existing leading limits
from PICO on spin-dependent WIMP-proton coupling by nearly an order
of magnitude for WIMP masses greater than 3 GeV c-2 and
will have the ability to surpass all existing non-xenon bounds on
spin-independent WIMP-nucleon coupling for WIMP masses from 3 to 40
GeV c-2 .
Title: Light Pollution, Radio Interference, and Space Debris:
Threats and Opportunities in the 2020s
Authors: Hall, Jeffrey; Allen, Lori; Arion, Douglas; Barentine, John;
Caton, Daniel; Liszt, Harvey; Lowenthal, James; McKenna, Dan; Pipkin,
Ashley; Seitzer, Patrick; Walker, Constance
Bibcode: 2019BAAS...51g..97H
Altcode: 2019astro2020U..97H
In this white paper, we will outline threats to astronomy in the
areas of light pollution, radio interference, and space debris, and we
will specify key principles and policy points that the AAS and other
advocates can use in mitigating these threats.
Title: Dark matter search results from the complete exposure of the
PICO-60 C3F8 bubble chamber
Authors: Amole, C.; Ardid, M.; Arnquist, I. J.; Asner, D. M.; Baxter,
D.; Behnke, E.; Bressler, M.; Broerman, B.; Cao, G.; Chen, C. J.;
Chowdhury, U.; Clark, K.; Collar, J. I.; Cooper, P. S.; Coutu,
C. B.; Cowles, C.; Crisler, M.; Crowder, G.; Cruz-Venegas, N. A.;
Dahl, C. E.; Das, M.; Fallows, S.; Farine, J.; Felis, I.; Filgas, R.;
Girard, F.; Giroux, G.; Hall, J.; Hardy, C.; Harris, O.; Hillier, T.;
Hoppe, E. W.; Jackson, C. M.; Jin, M.; Klopfenstein, L.; Kozynets,
T.; Krauss, C. B.; Laurin, M.; Lawson, I.; Leblanc, A.; Levine, I.;
Licciardi, C.; Lippincott, W. H.; Loer, B.; Mamedov, F.; Mitra, P.;
Moore, C.; Nania, T.; Neilson, R.; Noble, A. J.; Oedekerk, P.; Ortega,
A.; Piro, M. -C.; Plante, A.; Podviyanuk, R.; Priya, S.; Robinson,
A. E.; Sahoo, S.; Scallon, O.; Seth, S.; Sonnenschein, A.; Starinski,
N.; Štekl, I.; Sullivan, T.; Tardif, F.; Vázquez-Jáuregui, E.;
Walkowski, N.; Weima, E.; Wichoski, U.; Wierman, K.; Yan, Y.; Zacek,
V.; Zhang, J.; PICO Collaboration
Bibcode: 2019PhRvD.100b2001A
Altcode: 2019arXiv190204031A
Final results are reported from operation of the PICO-60
C3F8 dark matter detector, a bubble chamber
filled with 52 kg of C3 F8 located in the SNOLAB
underground laboratory. The chamber was operated at thermodynamic
thresholds as low as 1.2 keV without loss of stability. A new
blind 1404-kg-day exposure at 2.45 keV threshold was acquired with
approximately the same expected total background rate as the previous
1167-kg-day exposure at 3.3 keV. This increased exposure is enabled in
part by a new optical tracking analysis to better identify events near
detector walls, permitting a larger fiducial volume. These results set
the most stringent direct-detection constraint to date on the weakly
interacting massive particle (WIMP)-proton spin-dependent cross section
at 3.2 ×1 0-41 cm2 for a 25 GeV WIMP, improving
on previous PICO results for 3-5 GeV WIMPs by an order of magnitude.
Title: An Overview of Imaging from the InSight Lander
Authors: Maki, J. N.; Trebi-Ollennu, A.; Banerdt, W. B.; Sorice, C.;
Bailey, P.; Khan, O.; Kim, W.; Ali, K.; Lim, G.; Deen, R.; Abarca, H.;
Ruoff, N.; Hollins, G.; Andres, P.; Hall, J.; InSight Operations Team;
InSight Science Team
Bibcode: 2019LPICo2089.6403M
Altcode:
After landing on Mars on November 2018, the InSight lander began
returning image data from two color cameras. This overview talk will
provide a summary of the image data acquired.
Title: The PDS 110 observing campaign - photometric and spectroscopic
observations reveal eclipses are aperiodic
Authors: Osborn, H. P.; Kenworthy, M.; Rodriguez, J. E.; de Mooij,
E. J. W.; Kennedy, G. M.; Relles, H.; Gomez, E.; Hippke, M.; Banfi,
M.; Barbieri, L.; Becker, I. S.; Benni, P.; Berlind, P.; Bieryla,
A.; Bonnoli, G.; Boussier, H.; Brincat, S. M.; Briol, J.; Burleigh,
M. R.; Butterley, T.; Calkins, M. L.; Chote, P.; Ciceri, S.; Deldem,
M.; Dhillon, V. S.; Dose, E.; Dubois, F.; Dvorak, S.; Esquerdo, G. A.;
Evans, D. F.; Ferratfiat, S.; Fossey, S. J.; Günther, M. N.; Hall,
J.; Hambsch, F. -J.; Herrero, E.; Hills, K.; James, R.; Jayawardhana,
R.; Kafka, S.; Killestein, T. L.; Kotnik, C.; Latham, D. W.; Lemay,
D.; Lewin, P.; Littlefair, S.; Lopresti, C.; Mallonn, M.; Mancini,
L.; Marchini, A.; McCormac, J. J.; Murawski, G.; Myers, G.; Papini,
R.; Popov, V.; Quadri, U.; Quinn, S. N.; Raynard, L.; Rizzuti, L.;
Robertson, J.; Salvaggio, F.; Scholz, A.; Sfair, R.; Smith, A. M. S.;
Southworth, J.; Tan, T. G.; Vanaverbeke, S.; Waagen, E. O.; Watson,
C. A.; West, R. G.; Winter, O. C.; Wheatley, P. J.; Wilson, R. W.;
Zhou, G.
Bibcode: 2019MNRAS.485.1614O
Altcode: 2019arXiv190107981O; 2019MNRAS.tmp..287O
PDS 110 is a young disc-hosting star in the Orion OB1A association. Two
dimming events of similar depth and duration were seen in 2008
(WASP) and 2011 (KELT), consistent with an object in a closed
periodic orbit. In this paper, we present data from a ground-based
observing campaign designed to measure the star both photometrically
and spectroscopically during the time of predicted eclipse in 2017
September. Despite high-quality photometry, the predicted eclipse did
not occur, although coherent structure is present suggesting variable
amounts of stellar flux or dust obscuration. We also searched for radial
velocity (RV) oscillations caused by any hypothetical companion and
can rule out close binaries to 0.1Ms. A search of Sonneberg
plate archive data also enabled us to extend the photometric baseline
of this star back more than 50 yr, and similarly does not re-detect
any deep eclipses. Taken together, they suggest that the eclipses seen
in WASP and KELT photometry were due to aperiodic events. It would
seem that PDS 110 undergoes stochastic dimmings that are shallower
and of shorter duration than those of UX Ori variables, but may have
a similar mechanism.
Title: Imaging from the InSight Lander
Authors: Maki, J. N.; Trebi-Ollennu, A.; Banerdt, W. B.; Sorice, C.;
Bailey, P.; Khan, O.; Kim, W.; Ali, K.; Lim, G.; Deen, R.; Abarca,
H.; Ruoff, N.; Hollins, G.; Andres, P.; Hall, J.
Bibcode: 2019LPI....50.2176M
Altcode:
A view from the Mars InSight lander, as seen from the Instrument
Deployment Camera (IDC) and Instrument Context Camera (ICC).
Title: VizieR Online Data Catalog: 24 years monitoring of Sun and
Sun-like stars (Radick+, 2018)
Authors: Radick, R. R.; Lockwood, G. W.; Henry, G. W.; Hall, J. C.;
Pevtsov, A. A.
Bibcode: 2019yCat..18550075R
Altcode:
Starting in the late 1970s, variations in total solar irradiance (TSI)
have been monitored by radiometers aboard a series of spacecraft,
including the Total Irradiance Monitor (TIM) instrument on the
SOlar Radiation and Climate Experiment (SORCE) satellite from 2003
to the present. Observations to monitor relatively bright
stars very similar to the Sun have been made with the Solar-Stellar
Spectrograph (SSS) at Lowell Observatory and automatic photometric
telescopes (APTs) at Fairborn Observatory beginning in 1992 and
1993, respectively. In all, 72 stars, including 18 from the broader
R98-L07 (1998ApJS..118..239R and 2007ApJS..171..260L) sample, have
been observed at both locations, some for as long as 24 seasons. These
joint observations provide the primary stellar data for this paper. (3 data files).
Title: Nuclear-recoil energy scale in CDMS II silicon dark-matter
detectors
Authors: Agnese, R.; Anderson, A. J.; Aramaki, T.; Baker, W.;
Balakishiyeva, D.; Banik, S.; Barker, D.; Basu Thakur, R.; Bauer,
D. A.; Binder, T.; Borgland, A.; Bowles, M. A.; Brink, P. L.; Bunker,
R.; Cabrera, B.; Caldwell, D. O.; Calkins, R.; Cartaro, C.; Cerdeño,
D. G.; Chang, Y. -Y.; Chagani, H.; Chen, Y.; Cooley, J.; Cornell,
B.; Cushman, P.; Daal, M.; Doughty, T.; Dragowsky, E. M.; Esteban,
L.; Fallows, S.; Fascione, E.; Figueroa-Feliciano, E.; Fritts, M.;
Gerbier, G.; Germond, R.; Ghaith, M.; Godfrey, G. L.; Golwala, S. R.;
Hall, J.; Harris, H. R.; Holmgren, D.; Hong, Z.; Hsu, L.; Huber,
M. E.; Iyer, V.; Jardin, D.; Jastram, A.; Jena, C.; Kelsey, M. H.;
Kennedy, A.; Kubik, A.; Kurinsky, N. A.; Leder, A.; Lopez Asamar,
E.; Lukens, P.; MacDonell, D.; Mahapatra, R.; Mandic, V.; Mast, N.;
McCarthy, K. A.; Miller, E. H.; Mirabolfathi, N.; Moffatt, R. A.;
Mohanty, B.; Moore, D.; Morales Mendoza, J. D.; Nelson, J.; Oser,
S. M.; Page, K.; Page, W. A.; Partridge, R.; Penalver Martinez, M.;
Pepin, M.; Phipps, A.; Poudel, S.; Pyle, M.; Qiu, H.; Rau, W.; Redl,
P.; Reisetter, A.; Roberts, A.; Rogers, H. E.; Robinson, A. E.; Saab,
T.; Sadoulet, B.; Sander, J.; Schneck, K.; Schnee, R. W.; Scorza, S.;
Senapati, K.; Serfass, B.; Speller, D.; Di Stefano, P. C. F.; Stein,
M.; Street, J.; Tanaka, H. A.; Toback, D.; Underwood, R.; Villano,
A. N.; von Krosigk, B.; Welliver, B.; Wilson, J. S.; Wilson, M. J.;
Wright, D. H.; Yellin, S.; Yen, J. J.; Young, B. A.; Zhang, X.;
Zhao, X.
Bibcode: 2018NIMPA.905...71A
Altcode: 2018arXiv180302903A
The Cryogenic Dark Matter Search (CDMS II) experiment aims to
detect dark matter particles that elastically scatter from nuclei in
semiconductor detectors. The resulting nuclear-recoil energy depositions
are detected by ionization and phonon sensors. Neutrons produce a
similar spectrum of low-energy nuclear recoils in such detectors,
while most other backgrounds produce electron recoils. The absolute
energy scale for nuclear recoils is necessary to interpret results
correctly. The energy scale can be determined in CDMS II silicon
detectors using neutrons incident from a broad-spectrum 252Cf
source, taking advantage of a prominent resonance in the neutron
elastic scattering cross section of silicon at a recoil (neutron)
energy near 20 (182) keV. Results indicate that the phonon collection
efficiency for nuclear recoils is 4.8-0.9+0.7 %
lower than for electron recoils of the same energy. Comparisons of the
ionization signals for nuclear recoils to those measured previously by
other groups at higher electric fields indicate that the ionization
collection efficiency for CDMS II silicon detectors operated at ∼4
V/cm is consistent with 100% for nuclear recoils below 20 keV and
gradually decreases for larger energies to ∼75% at 100 keV. The
impact of these measurements on previously published CDMS II silicon
results is small.
Title: Many interesting things are afoot at the Navy Precision
Optical Interferometer
Authors: van Belle, G. T.; Armstrong, J. T.; Benson, J. A.; Baines,
E. K.; Bevilacqua, R. G.; Buschmann, T.; Clark, J. H.; DeGroff,
W. T.; Hall, J. C.; Hindsley, R. L.; Jorgensen, A.; Lindgren, A.;
Mozurkewich, D.; Muterspaugh, M.; Pooler, S. T.; Restaino, S. R.;
Schmitt, H. R.; Shankland, P.; Zavala, R. T.
Bibcode: 2018SPIE10701E..05V
Altcode:
The Navy Precision Optical Interferometer (NPOI) is currently
undergoing a fundamental renaissance in its functionality and
capabilities. Operationally, its fast delay line (FDL) infrastructure
is completing its upgrade from a VME/VxWorks foundation to a modern
PC/RTLinux core. The Classic beam combiner is being upgraded with the
New Classic FPGA-based backend, and the VISION beam combiner has been
upgraded over this past summer with low-noise EMCCD cameras, resulting
in substantial gains in sensitivity. Building on those infrastructure
improvements, substantial upgrades are also in progress. Three 1-meter
PlaneWave CDK1000 telescopes are being delivered to the site, along
with their relocatable enclosure-transporters, and stations are being
commissioned for those telescopes with baselines ranging from 8 meters
to 432 meters. Baseline-wavelength bootstrapping will be implemented
on the facility back-end with a near-infrared beam combiner under
development. Collectively, these improvements mark substantial progress
in taking the facility towards realizing its full intrinsic potential.
Title: Patterns of Variation for the Sun and Sun-like Stars
Authors: Radick, Richard R.; Lockwood, G. Wesley; Henry, Gregory W.;
Hall, Jeffrey C.; Pevtsov, Alexei A.
Bibcode: 2018ApJ...855...75R
Altcode:
We compare patterns of variation for the Sun and 72 Sun-like stars by
combining total and spectral solar irradiance measurements between 2003
and 2017 from the SORCE satellite, Strömgren b, y stellar photometry
between 1993 and 2017 from Fairborn Observatory, and solar and stellar
chromospheric Ca II H+K emission observations between 1992 and 2016
from Lowell Observatory. The new data and their analysis strengthen
the relationships found previously between chromospheric and brightness
variability on the decadal timescale of the solar activity cycle. Both
chromospheric H+K and photometric b, y variability among Sun-like stars
are related to average chromospheric activity by power laws on this
timescale. Young active stars become fainter as their H+K emission
increases, and older, less active, more Sun-age stars tend to show
a pattern of direct correlation between photometric and chromospheric
emission variations. The directly correlated pattern between total solar
irradiance and chromospheric Ca II emission variations shown by the Sun
appears to extend also to variations in the Strömgren b, y portion of
the solar spectrum. Although the Sun does not differ strongly from its
stellar age and spectral class mates in the activity and variability
characteristics that we have now studied for over three decades, it
may be somewhat unusual in two respects: (1) its comparatively smooth,
regular activity cycle, and (2) its rather low photometric brightness
variation relative to its chromospheric activity level and variation,
perhaps indicating that facular emission and sunspot darkening are
especially well-balanced on the Sun.
Title: Development of the Venera-D Mission Concept, from Science
Objectives to Mission Architecture
Authors: Senske, D.; Zasova, L.; Burdanov, A.; Economou, T.; Eismont,
N.; Gerasimov, M.; Gorinov, D.; Hall, J.; Ignatiev, N.; Ivanov, M.;
Lea Jessup, K.; Khatuntsev, I.; Korablev, O.; Kremic, T.; Limaye,
S.; Lomakin, I.; Martynov, M.; Ocampo, A.; Teselkin, S.; Vaisberg,
O.; Voronstsov, V.
Bibcode: 2018LPI....49.1243S
Altcode:
The development of the Venera-D concept is ongoing, focusing on science
goals and mission architecture.
Title: LED Street Lighting Solutions: Flagstaff, Arizona as a
Case Study
Authors: Hall, Jeffrey C.
Bibcode: 2018AAS...23112207H
Altcode:
Dark-sky protection in Flagstaff, Arizona extends back to 1958, with
the first ordinance in the City banning advertising floodlights. The
current ordinance, adopted in 1989, is comprehensive and has played a
critical role in maintaining the quality of the night sky for astronomy,
tourism, public enjoyment, and other purposes. Flagstaff, like many
communities around the world, is now working on a transition from
legacy bulb-based technology to LED for its outdoor lighting. The City,
Lowell Observatory, the U. S. Naval Observatory, and the Flagstaff
Dark Skies Coalition have been working intensively for two years to
identify an LED-based street lighting solution that will preserve
the City's dark skies while meeting municipal needs. We will soon
be installing test fixtures for an innovative solution incorporating
narrow-band amber LED and modest amounts of low-CCT white LED. In this
talk, I will review the types of LEDs available for outdoor lighting
and discuss the plans for Flagstaff's street lighting in the LED era,
which we hope will be a model for communities worldwide.
Title: Protecting Dark Skies as a State-Wide Resource
Authors: Allen, Lori E.; Walker, Constance E.; Hall, Jeffrey C.;
Larson, Steve; Williams, Grant; Falco, Emilio; Hinz, Joannah; Fortin,
Pascal; Brocious, Dan; Corbally, Christopher; Gabor, Paul; Veillet,
Christian; Shankland, Paul; Jannuzi, Buell; Cotera, Angela; Luginbuhl,
Christian
Bibcode: 2018AAS...23114208A
Altcode:
The state of Arizona contains the highest concentration of research
telescopes in the continental United States, contributing more than a
quarter of a billion dollars annually to the state's economy. Protecting
the dark skies above these observatories is both good for astronomy
and good for the state's economy. In this contribution we describe how
a coalition of Arizona observatories is working together to protect
our dark skies. Efforts date back to the creation of one of the
first Outdoor Lighting Codes in the United States and continue today,
including educational outreach, public policy engagement, and consensus
building. We review some proven strategies, highlight recent successes
and look at current threats.
Title: A Regional, Multi-Stakeholder Collaboration for Dark-Sky
Protection in Flagstaff, Arizona
Authors: Hall, Jeffrey C.
Bibcode: 2018AAS...23114204H
Altcode:
Flagstaff, Arizona is home to almost $200M in astronomical assets,
including Lowell Observatory's 4.3-meter Discovery Channel Telescope
and the Navy Precision Optical Interferometer, a partnership of Lowell,
the U. S. Naval Observatory, and the Naval Research Laboratory. The
City of Flagstaff and surrounding Coconino County have comprehensive
and effective dark-sky ordinances, but continued regional growth
has the potential to degrade the area's dark skies to a level at
which observatory missions could be compromised. As a result, a wide
array of stakeholders (the observatories, the City, the County, local
dark-sky advocates, the business and tourism communities, the national
parks and monuments, the Navajo Nation, the U. S. Navy, and others)
have engaged in three complementary efforts to ensure that Flagstaff
and Coconino County protect the area's dark skies while meeting the
needs of the various communities and providing for continued growth and
development. In this poster, I will present the status of Flagstaff's
conversion to LED outdoor lighting, the Mission Compatibility Study
carried out by the Navy to evaluate the dark-sky effects of buildout
in Flagstaff, and the Joint Land Use Study (JLUS) presently underway
among all the aforementioned stakeholders. Taken in sum, the efforts
represent a comprehensive and constructive approach to dark-sky
preservation region-wide, and they show what can be achieved when a
culture of dark-sky protection is present and deliberate efforts are
undertaken to maintain it for decades to come.
Title: Low-mass dark matter search with CDMSlite
Authors: Agnese, R.; Anderson, A. J.; Aralis, T.; Aramaki, T.;
Arnquist, I. J.; Baker, W.; Balakishiyeva, D.; Barker, D.; Basu Thakur,
R.; Bauer, D. A.; Binder, T.; Bowles, M. A.; Brink, P. L.; Bunker,
R.; Cabrera, B.; Caldwell, D. O.; Calkins, R.; Cartaro, C.; Cerdeño,
D. G.; Chang, Y.; Chagani, H.; Chen, Y.; Cooley, J.; Cornell, B.;
Cushman, P.; Daal, M.; Di Stefano, P. C. F.; Doughty, T.; Esteban,
L.; Fascione, E.; Figueroa-Feliciano, E.; Fritts, M.; Gerbier, G.;
Ghaith, M.; Godfrey, G. L.; Golwala, S. R.; Hall, J.; Harris, H. R.;
Hong, Z.; Hoppe, E. W.; Hsu, L.; Huber, M. E.; Iyer, V.; Jardin, D.;
Jastram, A.; Jena, C.; Kelsey, M. H.; Kennedy, A.; Kubik, A.; Kurinsky,
N. A.; Leder, A.; Loer, B.; Lopez Asamar, E.; Lukens, P.; MacDonell,
D.; Mahapatra, R.; Mandic, V.; Mast, N.; Miller, E. H.; Mirabolfathi,
N.; Moffatt, R. A.; Mohanty, B.; Morales Mendoza, J. D.; Nelson,
J.; Orrell, J. L.; Oser, S. M.; Page, K.; Page, W. A.; Partridge,
R.; Pepin, M.; Peñalver Martinez, M.; Phipps, A.; Poudel, S.; Pyle,
M.; Qiu, H.; Rau, W.; Redl, P.; Reisetter, A.; Reynolds, T.; Roberts,
A.; Robinson, A. E.; Rogers, H. E.; Saab, T.; Sadoulet, B.; Sander,
J.; Schneck, K.; Schnee, R. W.; Scorza, S.; Senapati, K.; Serfass,
B.; Speller, D.; Stein, M.; Street, J.; Tanaka, H. A.; Toback, D.;
Underwood, R.; Villano, A. N.; von Krosigk, B.; Welliver, B.; Wilson,
J. S.; Wilson, M. J.; Wright, D. H.; Yellin, S.; Yen, J. J.; Young,
B. A.; Zhang, X.; Zhao, X.; SuperCDMS Collaboration
Bibcode: 2018PhRvD..97b2002A
Altcode:
The SuperCDMS experiment is designed to directly detect weakly
interacting massive particles (WIMPs) that may constitute the dark
matter in our Galaxy. During its operation at the Soudan Underground
Laboratory, germanium detectors were run in the CDMSlite mode to gather
data sets with sensitivity specifically for WIMPs with masses <10
GeV /c2 . In this mode, a higher detector-bias voltage is
applied to amplify the phonon signals produced by drifting charges. This
paper presents studies of the experimental noise and its effect on the
achievable energy threshold, which is demonstrated to be as low as 56
eVee (electron equivalent energy). The detector-biasing
configuration is described in detail, with analysis corrections for
voltage variations to the level of a few percent. Detailed studies of
the electric-field geometry, and the resulting successful development
of a fiducial parameter, eliminate poorly measured events, yielding an
energy resolution ranging from ∼9 eVee at 0 keV to 101
eVee at ∼10 keVee . New results are derived
for astrophysical uncertainties relevant to the WIMP-search limits,
specifically examining how they are affected by variations in the
most probable WIMP velocity and the Galactic escape velocity. These
variations become more important for WIMP masses below 10 GeV
/c2 . Finally, new limits on spin-dependent low-mass
WIMP-nucleon interactions are derived, with new parameter space excluded
for WIMP masses ≲3 GeV /c2.
Title: Performance Characterization of HT Actuator for Venus
Authors: Rehnmark, F.; Bailey, J.; Cloninger, E.; Zacny, K.; Hall,
J.; Sherrill, K.; Melko, J.; Kriechbaum, K.; Wilcox, B.
Bibcode: 2017LPICo2061.8038R
Altcode:
A high temperature (HT) actuator capable of operating in the harsh
environment found on the surface of Venus has been built and tested
in rock drilling trials at JPL’s Venus Materials Test Facility.
Title: The Venera-D Mission Concept, Report on the Activities of
the Joint Science Definition Team
Authors: Senske, D.; Zasova, L.; Economou, T.; Eismont, N.; Gerasimov,
M.; Gorinov, D.; Hall, J.; Ignatiev, N.; Ivanov, M.; Lea Jessup, K.;
Khatuntsev, I.; Korablev, O.; Kremic, T.; Limaye, S.; Lomakin, I.;
Martynov, A.; Ocampo, A.; Vaisberg, O.; Burdanov, A.; Teselkin, S.;
Vorontsov, V.
Bibcode: 2017LPICo2061.8014S
Altcode:
This report will summarize the activities of the Venera-D Joint Science
Definition Team. The focus will be on the mission architecture and
the outcome of a Venus modeling workshop held in Moscow.
Title: Evolution of Long Term Variability in Solar Analogs
Authors: Egeland, Ricky; Soon, Willie; Baliunas, Sallie; Hall,
Jeffrey C.; Henry, Gregory W.
Bibcode: 2017IAUS..328..329E
Altcode: 2017arXiv170402388E
Earth is the only planet known to harbor life, therefore we may
speculate on how the nature of the Sun-Earth interaction is relevant
to life on Earth, and how the behavior of other stars may influence the
development of life on their planetary systems. We study the long-term
variability of a sample of five solar analog stars using composite
chromospheric activity records up to 50 years in length and synoptic
visible-band photometry about 20 years long. This sample covers a
large range of stellar ages which we use to represent the evolution in
activity for solar mass stars. We find that young, fast rotators have an
amplitude of variability many times that of the solar cycle, while old,
slow rotators have very little variability. We discuss the possible
impacts of this variability on young Earth and exoplanet climates.
Title: VizieR Online Data Catalog: Calibrated solar S-index time
series (Egeland+, 2017)
Authors: Egeland, R.; Soon, W.; Baliunas, S.; Hall, J. C.; Pevtsov,
A. A.; Bertello, L.
Bibcode: 2017yCat..18350025E
Altcode:
The Mount Wilson HK Program observed the Moon with both the HKP-1
and HKP-2 instruments. After removing 11 obvious outliers, there
are 162 HKP-1 observations taken from 1966 September 2 to 1977 June
4 with the Mount Wilson 100 inch reflector, covering the maximum
of cycle 20 and the cycle 20-21 minimum. As mentioned in Baliunas+
(1995ApJ...438..269B), observations of the Moon resumed in 1993 with
the HKP-2 instrument. After removing 10 obvious outliers, there are 75
HKP-2 observations taken from 1994 March 27 to 2002 November 23 with
the Mount Wilson 60 inch reflector, covering the end of cycle 22 and
the cycle 23 minimum, extending just past the cycle 23 maximum. The
end of observations coincides with the unfortunate termination of
the HK Project in 2003. We seek to extend our time series of
solar variability beyond cycle 23 by establishing a proxy to the
NSO Sacramento Peak (NSO/SP) observations taken from 1976 to 2016,
covering cycles 21 to 24. The spectral intensity scale is set by
integrating a 0.53Å band centered at 3934.869Å in the K-line wing
and setting it to the fixed value of 0.162. We extend the S-index
record back to cycle 20 using the composite K time series of Bertello+
(2016SoPh..291.2967B). See section 3 for further explanations. (1
data file).
Title: Low-Mass Dark Matter Search with CDMSlite
Authors: SuperCDMS Collaboration; Agnese, R.; Anderson, A. J.; Aralis,
T.; Aramaki, T.; Arnquist, I. J.; Baker, W.; Balakishiyeva, D.; Barker,
D.; Basu Thakur, R.; Bauer, D. A.; Binder, T.; Bowles, M. A.; Brink,
P. L.; Bunker, R.; Cabrera, B.; Caldwell, D. O.; Calkins, R.; Cartaro,
C.; Cerdeno, D. G.; Chang, Y.; Chagani, H.; Chen, Y.; Cooley, J.;
Cornell, B.; Cushman, P.; Daal, M.; Di Stefano, P. C. F.; Doughty,
T.; Esteban, L.; Fascione, E.; Figueroa-Feliciano, E.; Fritts, M.;
Gerbier, G.; Ghaith, M.; Godfrey, G. L.; Golwala, S. R.; Hall, J.;
Harris, H. R.; Hong, Z.; Hoppe, E. W.; Hsu, L.; Huber, M. E.; Iyer,
V.; Jardin, D.; Jastram, A.; Jena, C.; Kelsey, M. H.; Kennedy, A.;
Kubik, A.; Kurinsky, N. A.; Leder, A.; Loer, B.; Lopez Asamar, E.;
Lukens, P.; MacDonell, D.; Mahapatra, R.; Mandic, V.; Mast, N.; Miller,
E. H.; Mirabolfathi, N.; Moffatt, R. A.; Mohanty, B.; Morales Mendoza,
J. D.; Nelson, J.; Orrell, J. L.; Oser, S. M.; Page, K.; Page, W. A.;
Partridge, R.; Pepin, M.; Penalver Martinez, M.; Phipps, A.; Poudel,
S.; Pyle, M.; Qiu, H.; Rau, W.; Redl, P.; Reisetter, A.; Reynolds,
T.; Roberts, A.; Robinson, A. E.; Rogers, H. E.; Saab, T.; Sadoulet,
B.; Sander, J.; Schneck, K.; Schnee, R. W.; Scorza, S.; Senapati,
K.; Serfass, B.; Speller, D.; Stein, M.; Street, J.; Tanaka, H. A.;
Toback, D.; Underwood, R.; Villano, A. N.; von Krosigk, B.; Welliver,
B.; Wilson, J. S.; Wilson, M. J; Wright, D. H.; Yellin, S.; Yen,
J. J.; Young, B. A.; Zhang, X.; Zhao, X.
Bibcode: 2017arXiv170701632S
Altcode:
The SuperCDMS experiment is designed to directly detect weakly
interacting massive particles (WIMPs) that may constitute the dark
matter in our Galaxy. During its operation at the Soudan Underground
Laboratory, germanium detectors were run in the CDMSlite mode to
gather data sets with sensitivity specifically for WIMPs with masses
${<}$10 GeV/$c^2$. In this mode, a higher detector-bias voltage is
applied to amplify the phonon signals produced by drifting charges. This
paper presents studies of the experimental noise and its effect on the
achievable energy threshold, which is demonstrated to be as low as 56
eV$_{\text{ee}}$ (electron equivalent energy). The detector-biasing
configuration is described in detail, with analysis corrections for
voltage variations to the level of a few percent. Detailed studies of
the electric-field geometry, and the resulting successful development
of a fiducial parameter, eliminate poorly measured events, yielding
an energy resolution ranging from ${\sim}$9 eV$_{\text{ee}}$ at
0 keV to 101 eV$_{\text{ee}}$ at ${\sim}$10 eV$_{\text{ee}}$. New
results are derived for astrophysical uncertainties relevant to the
WIMP-search limits, specifically examining how they are affected
by variations in the most probable WIMP velocity and the Galactic
escape velocity. These variations become more important for WIMP
masses below 10 GeV/$c^2$. Finally, new limits on spin-dependent
low-mass WIMP-nucleon interactions are derived, with new parameter
space excluded for WIMP masses $\lesssim$3 GeV/$c^2$
Title: Dark Matter Search Results from the PICO -60 C
3F8 Bubble Chamber
Authors: Amole, C.; Ardid, M.; Arnquist, I. J.; Asner, D. M.; Baxter,
D.; Behnke, E.; Bhattacharjee, P.; Borsodi, H.; Bou-Cabo, M.; Campion,
P.; Cao, G.; Chen, C. J.; Chowdhury, U.; Clark, K.; Collar, J. I.;
Cooper, P. S.; Crisler, M.; Crowder, G.; Dahl, C. E.; Das, M.; Fallows,
S.; Farine, J.; Felis, I.; Filgas, R.; Girard, F.; Giroux, G.; Hall,
J.; Harris, O.; Hoppe, E. W.; Jin, M.; Krauss, C. B.; Laurin, M.;
Lawson, I.; Leblanc, A.; Levine, I.; Lippincott, W. H.; Mamedov, F.;
Maurya, D.; Mitra, P.; Nania, T.; Neilson, R.; Noble, A. J.; Olson, S.;
Ortega, A.; Plante, A.; Podviyanuk, R.; Priya, S.; Robinson, A. E.;
Roeder, A.; Rucinski, R.; Scallon, O.; Seth, S.; Sonnenschein, A.;
Starinski, N.; Štekl, I.; Tardif, F.; Vázquez-Jáuregui, E.; Wells,
J.; Wichoski, U.; Yan, Y.; Zacek, V.; Zhang, J.; PICO Collaboration
Bibcode: 2017PhRvL.118y1301A
Altcode: 2017arXiv170207666A
New results are reported from the operation of the PICO-60 dark
matter detector, a bubble chamber filled with 52 kg of C3
F8 located in the SNOLAB underground laboratory. As in
previous PICO bubble chambers, PICO -60 C 3F8
exhibits excellent electron recoil and alpha decay rejection, and the
observed multiple-scattering neutron rate indicates a single-scatter
neutron background of less than one event per month. A blind analysis of
an efficiency-corrected 1167-kg day exposure at a 3.3-keV thermodynamic
threshold reveals no single-scattering nuclear recoil candidates,
consistent with the predicted background. These results set the most
stringent direct-detection constraint to date on the weakly interacting
massive particle (WIMP)-proton spin-dependent cross section at 3.4
×10-41 cm2 for a 30 -GeV c-2 WIMP,
more than 1 order of magnitude improvement from previous PICO results.
Title: VISAGE Rock Sampling Drill
Authors: Rehnmark, F.; Cloninger, E.; Hyman, C.; Zacny, K.; Kriechbaum,
K.; Hall, J.; Melko, J.; Bailey, J.; Wilcox, B.; Sherrill, K.
Bibcode: 2017LPICo2022.8038R
Altcode:
A rock sampling drill capable of operating in the high temperature and
pressure environment found on the surface of Venus has been built and
tested at JPL’s Venus Materials Test Facility (VMTF).
Title: Projected sensitivity of the SuperCDMS SNOLAB experiment
Authors: Agnese, R.; Anderson, A. J.; Aramaki, T.; Arnquist, I.;
Baker, W.; Barker, D.; Basu Thakur, R.; Bauer, D. A.; Borgland,
A.; Bowles, M. A.; Brink, P. L.; Bunker, R.; Cabrera, B.; Caldwell,
D. O.; Calkins, R.; Cartaro, C.; Cerdeño, D. G.; Chagani, H.; Chen,
Y.; Cooley, J.; Cornell, B.; Cushman, P.; Daal, M.; Di Stefano,
P. C. F.; Doughty, T.; Esteban, L.; Fallows, S.; Figueroa-Feliciano,
E.; Fritts, M.; Gerbier, G.; Ghaith, M.; Godfrey, G. L.; Golwala,
S. R.; Hall, J.; Harris, H. R.; Hofer, T.; Holmgren, D.; Hong, Z.;
Hoppe, E.; Hsu, L.; Huber, M. E.; Iyer, V.; Jardin, D.; Jastram, A.;
Kelsey, M. H.; Kennedy, A.; Kubik, A.; Kurinsky, N. A.; Leder, A.;
Loer, B.; Lopez Asamar, E.; Lukens, P.; Mahapatra, R.; Mandic, V.;
Mast, N.; Mirabolfathi, N.; Moffatt, R. A.; Morales Mendoza, J. D.;
Orrell, J. L.; Oser, S. M.; Page, K.; Page, W. A.; Partridge, R.;
Pepin, M.; Phipps, A.; Poudel, S.; Pyle, M.; Qiu, H.; Rau, W.; Redl,
P.; Reisetter, A.; Roberts, A.; Robinson, A. E.; Rogers, H. E.; Saab,
T.; Sadoulet, B.; Sander, J.; Schneck, K.; Schnee, R. W.; Serfass,
B.; Speller, D.; Stein, M.; Street, J.; Tanaka, H. A.; Toback, D.;
Underwood, R.; Villano, A. N.; von Krosigk, B.; Welliver, B.; Wilson,
J. S.; Wright, D. H.; Yellin, S.; Yen, J. J.; Young, B. A.; Zhang,
X.; Zhao, X.; SuperCDMS Collaboration
Bibcode: 2017PhRvD..95h2002A
Altcode: 2016arXiv161000006A
SuperCDMS SNOLAB will be a next-generation experiment aimed
at directly detecting low-mass particles (with masses ≤10
GeV /c2 ) that may constitute dark matter by using
cryogenic detectors of two types (HV and iZIP) and two target
materials (germanium and silicon). The experiment is being designed
with an initial sensitivity to nuclear recoil cross sections ∼1
×10-43 cm2 for a dark matter particle mass of
1 GeV /c2 , and with capacity to continue exploration to
both smaller masses and better sensitivities. The phonon sensitivity
of the HV detectors will be sufficient to detect nuclear recoils
from sub-GeV dark matter. A detailed calibration of the detector
response to low-energy recoils will be needed to optimize running
conditions of the HV detectors and to interpret their data for
dark matter searches. Low-activity shielding, and the depth of
SNOLAB, will reduce most backgrounds, but cosmogenically produced
<mml:mmultiscripts>H 3 </mml:mmultiscripts> and naturally
occurring <mml:mmultiscripts>Si 32 </mml:mmultiscripts> will
be present in the detectors at some level. Even if these backgrounds are
10 times higher than expected, the science reach of the HV detectors
would be over 3 orders of magnitude beyond current results for a dark
matter mass of 1 GeV /c2 . The iZIP detectors are relatively
insensitive to variations in detector response and backgrounds, and
will provide better sensitivity for dark matter particles with masses
≳5 GeV /c2 . The mix of detector types (HV and iZIP),
and targets (germanium and silicon), planned for the experiment, as
well as flexibility in how the detectors are operated, will allow
us to maximize the low-mass reach, and understand the backgrounds
that the experiment will encounter. Upgrades to the experiment,
perhaps with a variety of ultra-low-background cryogenic detectors,
will extend dark matter sensitivity down to the "neutrino floor,"
where coherent scatters of solar neutrinos become a limiting background.
Title: Sample Acquisition Drill for Venus In Situ Explorer (VISE)
Authors: Rehnmark, F.; Zacny, K.; Hall, J.; Cloninger, E.; Hyman, C.;
Kriechbaum, K.; Melko, J.; Rabinovitch, J.; Wilcox, B.; Lambert, J.;
Traeden, N.; Bailey, J.
Bibcode: 2017LPI....48.1367R
Altcode:
We present development and testing of Venus drill for New Frontiers
Venus In Situ Explorer (VISE).
Title: Lowell Observatory's Discovery Channel Telescope
Authors: Hall, Jeffrey C.
Bibcode: 2017AAS...22912601H
Altcode:
Lowell Observatory broke ground on its 4.3-meter Discovery Channel
Telescope (DCT) in July 2005 and celebrated first light for the
telescope in July 2012. In this overview to this special session, I
will discuss the origin and development of the project, the telescope's
general specifications and performance, its current operating status,
and the initial instrument suite.
Title: The Mount Wilson Observatory S-index of the Sun
Authors: Egeland, Ricky; Soon, Willie; Baliunas, Sallie; Hall,
Jeffrey C.; Pevtsov, Alexei A.; Bertello, Luca
Bibcode: 2017ApJ...835...25E
Altcode: 2016arXiv161104540E
The most commonly used index of stellar magnetic activity is the
instrumental flux scale of singly ionized calcium H & K line
core emission, S, developed by the Mount Wilson Observatory (MWO)
HK Project, or the derivative index {R}{HK}\prime
. Accurately placing the Sun on the S scale is important for
comparing solar activity to that of the Sun-like stars. We present
previously unpublished measurements of the reflected sunlight from
the Moon using the second-generation MWO HK photometer during solar
cycle 23 and determine cycle minimum {S}23,\min =0.1634+/-
0.0008, amplitude {{Δ }}{S}23=0.0143+/- 0.0012, and mean
< {S}23> =0.1701+/- 0.0005. By establishing a proxy
relationship with the closely related National Solar Observatory
Sacramento Peak calcium K emission index, itself well correlated with
the Kodaikanal Observatory plage index, we extend the MWO S time series
to cover cycles 15-24 and find on average < {S}\min >
=0.1621+/- 0.0008, < {{Δ }}{S}{cyc}> =0.0145+/-
0.0012, < {S}{cyc}> =0.1694+/- 0.0005. Our measurements
represent an improvement over previous estimates that relied on stellar
measurements or solar proxies with non-overlapping time series. We
find good agreement from these results with measurements by the
Solar-Stellar Spectrograph at Lowell Observatory, an independently
calibrated instrument, which gives us additional confidence that we
have accurately placed the Sun on the S-index flux scale.
Title: A solar-like magnetic cycle on the mature K-dwarf 61 Cygni A
(HD 201091)
Authors: Boro Saikia, S.; Jeffers, S. V.; Morin, J.; Petit, P.;
Folsom, C. P.; Marsden, S. C.; Donati, J. -F.; Cameron, R.; Hall,
J. C.; Perdelwitz, V.; Reiners, A.; Vidotto, A. A.
Bibcode: 2016A&A...594A..29B
Altcode: 2016arXiv160601032B
Context. The long-term monitoring of magnetic cycles in cool stars is a
key diagnostic in understanding how dynamo generation and amplification
of magnetic fields occur in stars similar in structure to the Sun.
Aims: We investigated the temporal evolution of a possible magnetic
cycle of 61 Cyg A. The magnetic cycle is determined from 61 Cyg A's
large-scale field over its activity cycle using spectropolarimetric
observations and compared to the solar large-scale magnetic field.
Methods: We used the tomographic technique of Zeeman Doppler imaging
(ZDI) to reconstruct the large-scale magnetic geometry of 61 Cyg A
over multiple observational epochs spread over a time span of nine
years. We investigated the time evolution of the different components
of the large-scale field and compared it with the evolution of the
star's chromospheric activity by measuring the flux in three different
chromospheric indicators: Ca II H&K, Hα and Ca II infrared triplet
lines. We also compared our results with the star's coronal activity
using XMM-Newton observations.
Results: The large-scale magnetic
geometry of 61 Cyg A exhibits polarity reversals in both poloidal and
toroidal field components, in phase with its chromospheric activity
cycle. We also detect weak solar-like differential rotation with
a shear level similar to that of the Sun. During our observational
time span of nine years, 61 Cyg A exhibits solar- like variations in
its large-scale field geometry as it evolves from minimum activity
to maximum activity and vice versa. During its activity minimum in
epoch 2007.59, ZDI reconstructs a simple dipolar geometry which becomes
more complex when it approaches activity maximum in epoch 2010.55. The
radial field flips polarity and reverts back to a simple geometry in
epoch 2013.61. The field is strongly dipolar and the evolution of the
dipole component of the field is reminiscent of solar behaviour. The
polarity reversal of the large-scale field indicates a magnetic cycle
that is in phase with the chromospheric and coronal cycle.
Title: Dynamo Sensitivity In Solar Analogs With 50 Years Of Ca II
H & K Activity
Authors: Egeland, Ricky; Soon, Willie; Baliunas, Sallie; Hall,
Jeffrey C.; Pevtsov, Alexei A.; Henry, Gregory W.
Bibcode: 2016csss.confE...6E
Altcode: 2016csss.confE..73E; 2016arXiv160904756E
The Sun has a steady 11-year cycle in magnetic activity most well-known
by the rising and falling in the occurrence of dark sunspots on the
solar disk in visible bandpasses. The 11-year cycle is also manifest
in the variations of emission in the Ca II H & K line cores, due to
non-thermal (i.e. magnetic) heating in the lower chromosphere. The large
variation in Ca II H & K emission allows for study of the patterns
of long-term variability in other stars thanks to synoptic monitoring
with the Mount Wilson Observatory HK photometers (1966-2003) and Lowell
Observatory Solar-Stellar Spectrograph (1994-present). Overlapping
measurements for a set of 27 nearby solar-analog (spectral types G0-G5)
stars were used to calibrate the two instruments and construct time
series of magnetic activity up to 50 years in length. Precise properties
of fundamental importance to the dynamo are available from Hipparcos,
the Geneva-Copenhagen Survey, and CHARA interferometry. Using these
long time series and measurements of fundamental properties, we do
a comparative study of stellar "twins" to explore the sensitivity
of the stellar dynamo to small changes to structure, rotation, and
composition. We also compare this sample to the Sun and find hints
that the regular periodic variability of the solar cycle may be rare
among its nearest neighbors in parameter space.
Title: The Solar Dynamo Zoo
Authors: Egeland, Ricky; Soon, Willie; Baliunas, Sallie; Hall,
Jeffrey C.; Pevtsov, Alexei A.; Henry, Gregory W.
Bibcode: 2016csss.confE..72E
Altcode:
We present composite time series of Ca II H & K line core emission
indices of up to 50 years in length for a set of 27 solar-analog stars
(spectral types G0-G5; within 10% of the solar mass) and the Sun. These
unique data are available thanks to the long-term dedicated efforts
of the Mount Wilson Observatory HK project, the Lowell Observatory
Solar-Stellar Spectrograph, and the National Solar Observatory/Air Force
Research Laboratory/Sacramento Peak K-line monitoring program. The Ca II
H & K emission originates in the lower chromosphere and is strongly
correlated with the presence of magnetic plage regions in the Sun. These
synoptic observations allow us to trace the patterns long-term magnetic
variability and explore dynamo behavior over a wide range of rotation
regimes and stellar evolution timescales.In this poster, the Ca HK
observations are expressed using the Mount Wilson S-index. Each time
series is accompanied by a Lomb-Scargle periodogram, fundemental stellar
parameters derived from the Geneva-Copenhagen Survey, and statistics
derived from the time series including the median S-index value and
seasonal and long-term amplitudes. Statistically significant periodogram
peaks are ranked according to a new cycle quality metric. We find that
clear, simple, Sun-like cycles are the minority in this sample.
Title: Dynamo Sensitivity in Solar Analogs with 50 Years of Ca II
H & K Activity
Authors: Egeland, Ricky; Soon, Willie H.; Baliunas, Sallie L.; Hall,
Jeffrey C.; Pevtsov, Alexei A.; Henry, Gregory W.
Bibcode: 2016SPD....4720307E
Altcode:
The Sun has a steady 11-year cycle in magnetic activity most well-known
by the rising and falling in the occurrence of dark sunspots on the
solar disk in visible bandpasses. The 11-year cycle is also manifest
in the variations of emission in the Ca II H & K line cores, due to
non-thermal (i.e. magnetic) heating in the lower chromosphere. The large
variation in Ca II H & K emission allows for study of the patterns
of long-term variability in other stars thanks to synoptic monitoring
with the Mount Wilson Observatory HK photometers (1966-2003) and Lowell
Observatory Solar-Stellar Spectrograph (1994-present). Overlapping
measurements for a set of 27 nearby solar-analog (spectral types G0-G5)
stars were used to calibrate the two instruments and construct time
series of magnetic activity up to 50 years in length. Precise properties
of fundamental importance to the dynamo are available from Hipparcos,
the Geneva-Copenhagen Survey, and CHARA interferometry. Using these
long time series and measurements of fundamental properties, we do
a comparative study of stellar "twins" to explore the sensitivity
of the stellar dynamo to small changes to structure, rotation, and
composition. We also compare this sample to the Sun and find hints
that the regular periodic variability of the solar cycle may be rare
among its nearest neighbors in parameter space.
Title: The Solar Dynamo Zoo
Authors: Egeland, Ricky; Soon, Willie H.; Baliunas, Sallie L.; Hall,
Jeffrey C.; Pevtsov, Alexei A.; Henry, Gregory W.
Bibcode: 2016SPD....47.1103E
Altcode:
We present composite time series of Ca II H & K line core emission
indices of up to 50 years in length for a set of 27 solar-analog stars
(spectral types G0-G5; within ~10% of the solar mass) and the Sun. These
unique data are available thanks to the long-term dedicated efforts
of the Mount Wilson Observatory HK project, the Lowell Observatory
Solar-Stellar Spectrograph, and the National Solar Observatory/Air Force
Research Laboratory/Sacremento Peak K-line monitoring program. The
Ca II H & K emission originates in the lower chromosphere and is
strongly correlated with the presence of magnetic plage regions in
the Sun. These synoptic observations allow us to trace the patterns
long-term magnetic variability and explore dynamo behavior over a wide
range of rotation regimes and stellar evolution timescales.
Title: Improved dark matter search results from PICO-2L Run 2
Authors: Amole, C.; Ardid, M.; Arnquist, I. J.; Asner, D. M.; Baxter,
D.; Behnke, E.; Bhattacharjee, P.; Borsodi, H.; Bou-Cabo, M.; Brice,
S. J.; Broemmelsiek, D.; Clark, K.; Collar, J. I.; Cooper, P. S.;
Crisler, M.; Dahl, C. E.; Das, M.; Debris, F.; Fallows, S.; Farine, J.;
Felis, I.; Filgas, R.; Fines-Neuschild, M.; Girard, F.; Giroux, G.;
Hall, J.; Harris, O.; Hoppe, E. W.; Jackson, C. M.; Jin, M.; Krauss,
C. B.; Lafrenière, M.; Laurin, M.; Lawson, I.; Leblanc, A.; Levine,
I.; Lippincott, W. H.; Mann, E.; Martin, J. P.; Maurya, D.; Mitra, P.;
Olson, S.; Neilson, R.; Noble, A. J.; Plante, A.; Podviianiuk, R. B.;
Priya, S.; Robinson, A. E.; Ruschman, M.; Scallon, O.; Sonnenschein,
A.; Starinski, N.; Štekl, I.; Vázquez-Jáuregui, E.; Wells, J.;
Wichoski, U.; Zacek, V.; Zhang, J.; PICO Collaboration
Bibcode: 2016PhRvD..93f1101A
Altcode: 2016arXiv160103729A
New data are reported from a second run of the 2-liter PICO-2L
C3 F8 bubble chamber with a total exposure of
129 kg-days at a thermodynamic threshold energy of 3.3 keV. These data
show that measures taken to control particulate contamination in the
superheated fluid resulted in the absence of the anomalous background
events observed in the first run of this bubble chamber. One single
nuclear-recoil event was observed in the data, consistent both with
the predicted background rate from neutrons and with the observed rate
of unambiguous multiple-bubble neutron scattering events. The chamber
exhibits the same excellent electron-recoil and alpha decay rejection
as was previously reported. These data provide the most stringent
direct detection constraints on weakly interacting massive particle
(WIMP)-proton spin-dependent scattering to date for WIMP masses <50
GeV /c2 .
Title: Dark matter search results from the PICO-60 CF3
I bubble chamber
Authors: Amole, C.; Ardid, M.; Asner, D. M.; Baxter, D.; Behnke,
E.; Bhattacharjee, P.; Borsodi, H.; Bou-Cabo, M.; Brice, S. J.;
Broemmelsiek, D.; Clark, K.; Collar, J. I.; Cooper, P. S.; Crisler,
M.; Dahl, C. E.; Daley, S.; Das, M.; Debris, F.; Dhungana, N.;
Fallows, S.; Farine, J.; Felis, I.; Filgas, R.; Girard, F.; Giroux,
G.; Grandison, A.; Hai, M.; Hall, J.; Harris, O.; Jin, M.; Krauss,
C. B.; Lafrenière, M.; Laurin, M.; Lawson, I.; Levine, I.; Lippincott,
W. H.; Mann, E.; Maurya, D.; Mitra, P.; Neilson, R.; Noble, A. J.;
Plante, A.; Podviianiuk, R. B.; Priya, S.; Ramberg, E.; Robinson,
A. E.; Rucinski, R.; Ruschman, M.; Scallon, O.; Seth, S.; Simon,
P.; Sonnenschein, A.; Štekl, I.; Vázquez-Jáuregui, E.; Wells, J.;
Wichoski, U.; Zacek, V.; Zhang, J.; Shkrob, I. A.; PICO Collaboration
Bibcode: 2016PhRvD..93e2014A
Altcode: 2015arXiv151007754A
New data are reported from the operation of the PICO-60 dark matter
detector, a bubble chamber filled with 36.8 kg of CF3
I and located in the SNOLAB underground laboratory. PICO-60 is the
largest bubble chamber to search for dark matter to date. With an
analyzed exposure of 92.8 livedays, PICO-60 exhibits the same excellent
background rejection observed in smaller bubble chambers. Alpha decays
in PICO-60 exhibit frequency-dependent acoustic calorimetry, similar but
not identical to that reported recently in a C3 F8
bubble chamber. PICO-60 also observes a large population of unknown
background events, exhibiting acoustic, spatial, and timing behaviors
inconsistent with those expected from a dark matter signal. These
behaviors allow for analysis cuts to remove all background events
while retaining 48.2% of the exposure. Stringent limits on weakly
interacting massive particles interacting via spin-dependent proton
and spin-independent processes are set, and most interpretations of
the DAMA/LIBRA modulation signal as dark matter interacting with iodine
nuclei are ruled out.
Title: VizieR Online Data Catalog: S-index and Stroemgren LC of
HD30495 (Egeland+, 2015)
Authors: Egeland, R.; Metcalfe, T. S.; Hall, J. C.; Henry, G. W.
Bibcode: 2016yCat..18120012E
Altcode:
We analyze a combined 47-year time series of the Mount Wilson
S-index shown in Figure 1. The combined S time series contains
1285 measurements from five different instruments. The majority of
the measurements (624 measurements from 1967 to 2003) come from the
original Mount Wilson survey, calibrated as described in Baliunas et
al. (1995ApJ...438..269B). The next largest portion of the measurements
are from the solar-stellar spectrograph (SSS) at Lowell Observatory
(364 measurements from 1993 to 2014). Observations from the SMARTS
Southern HK survey using the RC Spec R~2500 spectrograph at 1.5m
telescope at CTIO are the third largest contribution (140 measurements
from 2008 to 2013). We add 108 measurements from 2011 to 2015 derived
from HARPS R~120000 spectra. Finally, we add 49 observations from 2002
to 2008 derived from R~55000 spectra of the Hamilton Spectrometer at
Lick Observatory. We also examined the 22-year time series of
differential photometry acquired with the T4 0.75m APT at Fairborn
Observatory, shown in Figure 1(c). These measurements, made in the
Stroemgren b (467nm) and y (547nm) bands, are a difference with respect
to the mean brightness of two stable comparison stars, HD 31414 and
HD 30606. (2 data files).
Title: Sun-like Magnetic Cycles in the Rapidly-rotating Young Solar
Analog HD 30495
Authors: Egeland, Ricky; Metcalfe, Travis S.; Hall, Jeffrey C.; Henry,
Gregory W.
Bibcode: 2015ApJ...812...12E
Altcode: 2015arXiv150703611E
A growing body of evidence suggests that multiple dynamo mechanisms
can drive magnetic variability on different timescales, not only in
the Sun but also in other stars. Many solar activity proxies exhibit
a quasi-biennial (∼2 year) variation, which is superimposed upon
the dominant 11 year cycle. A well-characterized stellar sample
suggests at least two different relationships between rotation period
and cycle period, with some stars exhibiting long and short cycles
simultaneously. Within this sample, the solar cycle periods are
typical of a more rapidly rotating star, implying that the Sun might
be in a transitional state or that it has an unusual evolutionary
history. In this work, we present new and archival observations of
dual magnetic cycles in the young solar analog HD 30495, a ∼1 Gyr
old G1.5 V star with a rotation period near 11 days. This star falls
squarely on the relationships established by the broader stellar sample,
with short-period variations at ∼1.7 years and a long cycle of ∼12
years. We measure three individual long-period cycles and find durations
ranging from 9.6 to 15.5 years. We find the short-term variability to be
intermittent, but present throughout the majority of the time series,
though its occurrence and amplitude are uncorrelated with the longer
cycle. These essentially solar-like variations occur in a Sun-like
star with more rapid rotation, though surface differential rotation
measurements leave open the possibility of a solar equivalence.
Title: Improved WIMP-search reach of the CDMS II germanium data
Authors: Agnese, R.; Anderson, A. J.; Asai, M.; Balakishiyeva, D.;
Barker, D.; Basu Thakur, R.; Bauer, D. A.; Billard, J.; Borgland,
A.; Bowles, M. A.; Brandt, D.; Brink, P. L.; Bunker, R.; Cabrera,
B.; Caldwell, D. O.; Calkins, R.; Cerdeño, D. G.; Chagani, H.;
Chen, Y.; Cooley, J.; Cornell, B.; Crewdson, C. H.; Cushman, P.;
Daal, M.; Di Stefano, P. C. F.; Doughty, T.; Esteban, L.; Fallows,
S.; Figueroa-Feliciano, E.; Godfrey, G. L.; Golwala, S. R.; Hall,
J.; Harris, H. R.; Hertel, S. A.; Hofer, T.; Holmgren, D.; Hsu, L.;
Huber, M. E.; Jardin, D.; Jastram, A.; Kamaev, O.; Kara, B.; Kelsey,
M. H.; Kennedy, A.; Kiveni, M.; Koch, K.; Leder, A.; Loer, B.; Lopez
Asamar, E.; Lukens, P.; Mahapatra, R.; Mandic, V.; McCarthy, K. A.;
Mirabolfathi, N.; Moffatt, R. A.; Oser, S. M.; Page, K.; Page, W. A.;
Partridge, R.; Pepin, M.; Phipps, A.; Prasad, K.; Pyle, M.; Qiu, H.;
Rau, W.; Redl, P.; Reisetter, A.; Ricci, Y.; Rogers, H. E.; Saab,
T.; Sadoulet, B.; Sander, J.; Schneck, K.; Schnee, R. W.; Scorza,
S.; Serfass, B.; Shank, B.; Speller, D.; Toback, D.; Upadhyayula,
S.; Villano, A. N.; Welliver, B.; Wilson, J. S.; Wright, D. H.;
Yang, X.; Yellin, S.; Yen, J. J.; Young, B. A.; Zhang, J.; SuperCDMS
Collaboration
Bibcode: 2015PhRvD..92g2003A
Altcode: 2015arXiv150405871A
CDMS II data from the five-tower runs at the Soudan Underground
Laboratory were reprocessed with an improved charge-pulse fitting
algorithm. Two new analysis techniques to reject surface-event
backgrounds were applied to the 612 kg days germanium-detector
weakly interacting massive particle (WIMP)-search exposure. An
extended analysis was also completed by decreasing the 10 keV analysis
threshold to ∼5 keV , to increase sensitivity near a WIMP mass of 8
GeV /c2 . After unblinding, there were zero candidate events
above a deposited energy of 10 keV and six events in the lower-threshold
analysis. This yielded minimum WIMP-nucleon spin-independent
scattering cross-section limits of 1.8 ×10-44 and 1.18
×10-41 at 90% confidence for 60 and 8.6 GeV /c2
WIMPs, respectively. This improves the previous CDMS II result by a
factor of 2.4 (2.7) for 60 (8.6 ) GeV /c2 WIMPs.
Title: WIMP-Search Results from the Second CDMSlite Run
Authors: SuperCDMS Collaboration; Agnese, R.; Anderson, A. J.; Aramaki,
T.; Asai, M.; Baker, W.; Balakishiyeva, D.; Barker, D.; Basu Thakur,
R.; Bauer, D. A.; Billard, J.; Borgland, A.; Bowles, M. A.; Brink,
P. L.; Bunker, R.; Cabrera, B.; Caldwell, D. O.; Calkins, R.; Cerdeno,
D. G.; Chagani, H.; Chen, Y.; Cooley, J.; Cornell, B.; Cushman, P.;
Daal, M.; Di Stefano, P. C. F.; Doughty, T.; Esteban, L.; Fallows,
S.; Figueroa-Feliciano, E.; Ghaith, M.; Godfrey, G. L.; Golwala,
S. R.; Hall, J.; Harris, H. R.; Hofer, T.; Holmgren, D.; Hsu, L.;
Huber, M. E.; Jardin, D.; Jastram, A.; Kamaev, O.; Kara, B.; Kelsey,
M. H.; Kennedy, A.; Leder, A.; Loer, B.; Lopez Asamar, E.; Lukens,
P.; Mahapatra, R.; Mandic, V.; Mast, N.; Mirabolfathi, N.; Moffatt,
R. A.; Morales Mendoza, J. D.; Oser, S. M.; Page, K.; Page, W. A.;
Partridge, R.; Pepin, M.; Phipps, A.; Prasad, K.; Pyle, M.; Qiu, H.;
Rau, W.; Redl, P.; Reisetter, A.; Ricci, Y.; Roberts, A.; Rogers,
H. E.; Saab, T.; Sadoulet, B.; Sander, J.; Schneck, K.; Schnee,
R. W.; Scorza, S.; Serfass, B.; Shank, B.; Speller, D.; Toback, D.;
Underwood, R.; Upadhyayula, S.; Villano, A. N.; Welliver, B.; Wilson,
J. S.; Wright, D. H.; Yellin, S.; Yen, J. J.; Young, B. A.; Zhang, J.
Bibcode: 2015arXiv150902448S
Altcode:
The CDMS low ionization threshold experiment (CDMSlite) uses cryogenic
germanium detectors operated at a relatively high bias voltage to
amplify the phonon signal in the search for weakly interacting massive
particles (WIMPs). Results are presented from the second CDMSlite
run with an exposure of 70 kg days, which reached an energy threshold
for electron recoils as low as 56 eV. A fiducialization cut reduces
backgrounds below those previously reported by CDMSlite. New parameter
space for the WIMP-nucleon spin-independent cross section is excluded
for WIMP masses between 1.6 and 5.5 GeV/$c^2$.
Title: Sun-like Magnetic Cycles in the Fast-Rotating Young Solar
Analog HD 30495
Authors: Egeland, Ricky; Metcalfe, Travis; Hall, Jeffrey C.; Henry,
Gregory W.
Bibcode: 2015IAUGA..2254437E
Altcode:
A growing body of evidence suggests that multiple dynamo mechanisms
can drive magnetic variability on different timescales, not only
in the Sun but also in other stars. Many solar activity proxies
exhibit a quasi-biennial (~2 year) variation, which is superimposed
upon the dominant 11 year cycle. A well-characterized stellar sample
suggests at least two different relationships between rotation period
and cycle period, with some stars exhibiting long and short cycles
simultaneously. Within this sample, the solar cycle periods are typical
of a more rapidly rotating star, implying that the Sun might be in a
transitional state or that it has an unusual evolutionary history. In
this work, we present new and archival observations of dual magnetic
and photometric cycles in the young solar analog HD 30495, a ~500
Myr-old G1.5V star with a rotation period near 11 days. This star
falls squarely on the relationships established by the broader stellar
sample, with short-period variations at ~1.6 years and a long cycle of
~12 years. We measure three individual cycle episodes and find cycle
durations ranging from 9.4-14.6 years. These essentially solar-like
variations occur in a solar-like star with faster-than-solar rotation,
though surface differential rotation measurements leave open the
possibility of a solar equivalence.
Title: A Tale of Two Regions: Site Protection Experience and Updated
Regulations in Arizona and the Canary Islands
Authors: Green, Richard F.; Diaz Castro, Javier; Allen, Lori; Alvarez
del Castillo, Elizabeth; Corbally, Christopher J.; Davis, Donald;
Falco, Emilio; Gabor, Paul; Hall, Jeffrey C.; Monrad, Christian Karl;
Williams, G. Grant
Bibcode: 2015IAUGA..2258199G
Altcode:
Some of the world's largest telescopes and largest concentrations of
telescopes are on sites in Arizona and the Canary Islands. Active site
protection efforts are underway in both regions; the common challenge is
getting out ahead of the LED revolution in outdoor lighting. We review
the work with local, regional, and national government bodies, with many
successful updates of outdoor lighting codes. A successful statewide
conference was held in Arizona to raise awareness of public officials
about issues of light pollution for astronomy, safety, wildlife, and
public health. We also highlight interactions with key entities near
critical sites, including mines and prisons, leading to upgrades of
their lighting to more astronomy-friendly form. We describe ongoing and
planned sky monitoring efforts, noting their importance in quantifying
the "impact on astronomy" increasingly requested by regulators.
Title: Activity and Brightness Variations of Sun-Like Stars
Authors: Hall, Jeffrey C.
Bibcode: 2015IAUGA..2256949H
Altcode:
Long-term observations of variations in Sun-like stars now span a half
century. The Mount Wilson Observatory (MWO) HK Project operated from
1966 to 2003, and the Lowell Observatory Solar-Stellar Spectrograph
(SSS) project has operated since 1994; together these programs provide
a record of chromospheric activity over multiple stellar cycles for
more than 100 stars of V < ~7.5. Long-term photometric monitoring
of Sun-like stars, including many of the MWO and SSS targets, began in
the early 1980s and continues today at the Fairborn Observatory south
of Tucson. I will review progress to date in combining and interpreting
the spectrosopic and photometric data sets, including some new results
from the most recent years of SSS and Fairborn data. I will also review
where deficiencies remain in reconciling and combining the major data
sets, and will discuss efforts presently underway to remedy this and
provide a long-term record for the benefit of the community.
Title: Dark Matter Search Results from the PICO-2L
C3F8 Bubble Chamber
Authors: Amole, C.; Ardid, M.; Asner, D. M.; Baxter, D.; Behnke,
E.; Bhattacharjee, P.; Borsodi, H.; Bou-Cabo, M.; Brice, S. J.;
Broemmelsiek, D.; Clark, K.; Collar, J. I.; Cooper, P. S.; Crisler,
M.; Dahl, C. E.; Daley, S.; Das, M.; Debris, F.; Dhungana, N.;
Farine, J.; Felis, I.; Filgas, R.; Fines-Neuschild, M.; Girard, F.;
Giroux, G.; Hai, M.; Hall, J.; Harris, O.; Jackson, C. M.; Jin, M.;
Krauss, C. B.; Lafrenière, M.; Laurin, M.; Lawson, I.; Levine, I.;
Lippincott, W. H.; Mann, E.; Martin, J. P.; Maurya, D.; Mitra, P.;
Neilson, R.; Noble, A. J.; Plante, A.; Podviianiuk, R. B.; Priya, S.;
Robinson, A. E.; Ruschman, M.; Scallon, O.; Seth, S.; Sonnenschein,
A.; Starinski, N.; Štekl, I.; Vázquez-Jáuregui, E.; Wells, J.;
Wichoski, U.; Zacek, V.; Zhang, J.; PICO Collaboration
Bibcode: 2015PhRvL.114w1302A
Altcode: 2015arXiv150300008A
New data are reported from the operation of a 2 liter
C3F8 bubble chamber in the SNOLAB underground
laboratory, with a total exposure of 211.5 kg days at four
different energy thresholds below 10 keV. These data show that
C3F8 provides excellent electron-recoil and alpha
rejection capabilities at very low thresholds. The chamber exhibits
an electron-recoil sensitivity of <3.5 ×1 0-10 and an
alpha rejection factor of >98.2 %. These data also include the first
observation of a dependence of acoustic signal on alpha energy. Twelve
single nuclear recoil event candidates were observed during the run. The
candidate events exhibit timing characteristics that are not consistent
with the hypothesis of a uniform time distribution, and no evidence
for a dark matter signal is claimed. These data provide the most
sensitive direct detection constraints on WIMP-proton spin-dependent
scattering to date, with significant sensitivity at low WIMP masses
for spin-independent WIMP-nucleon scattering.
Title: Dark matter effective field theory scattering in direct
detection experiments
Authors: Schneck, K.; Cabrera, B.; Cerdeño, D. G.; Mandic, V.;
Rogers, H. E.; Agnese, R.; Anderson, A. J.; Asai, M.; Balakishiyeva,
D.; Barker, D.; Basu Thakur, R.; Bauer, D. A.; Billard, J.; Borgland,
A.; Brandt, D.; Brink, P. L.; Bunker, R.; Caldwell, D. O.; Calkins,
R.; Chagani, H.; Chen, Y.; Cooley, J.; Cornell, B.; Crewdson, C. H.;
Cushman, P.; Daal, M.; Di Stefano, P. C. F.; Doughty, T.; Esteban, L.;
Fallows, S.; Figueroa-Feliciano, E.; Godfrey, G. L.; Golwala, S. R.;
Hall, J.; Harris, H. R.; Hofer, T.; Holmgren, D.; Hsu, L.; Huber,
M. E.; Jardin, D. M.; Jastram, A.; Kamaev, O.; Kara, B.; Kelsey,
M. H.; Kennedy, A.; Leder, A.; Loer, B.; Lopez Asamar, E.; Lukens,
P.; Mahapatra, R.; McCarthy, K. A.; Mirabolfathi, N.; Moffatt, R. A.;
Morales Mendoza, J. D.; Oser, S. M.; Page, K.; Page, W. A.; Partridge,
R.; Pepin, M.; Phipps, A.; Prasad, K.; Pyle, M.; Qiu, H.; Rau, W.;
Redl, P.; Reisetter, A.; Ricci, Y.; Roberts, A.; Saab, T.; Sadoulet,
B.; Sander, J.; Schnee, R. W.; Scorza, S.; Serfass, B.; Shank, B.;
Speller, D.; Toback, D.; Upadhyayula, S.; Villano, A. N.; Welliver,
B.; Wilson, J. S.; Wright, D. H.; Yang, X.; Yellin, S.; Yen, J. J.;
Young, B. A.; Zhang, J.; SuperCDMS Collaboration
Bibcode: 2015PhRvD..91i2004S
Altcode: 2015arXiv150303379S
We examine the consequences of the effective field theory (EFT)
of dark matter-nucleon scattering for current and proposed direct
detection experiments. Exclusion limits on EFT coupling constants
computed using the optimum interval method are presented for SuperCDMS
Soudan, CDMS II, and LUX, and the necessity of combining results from
multiple experiments in order to determine dark matter parameters is
discussed. We demonstrate that spectral differences between the standard
dark matter model and a general EFT interaction can produce a bias
when calculating exclusion limits and when developing signal models
for likelihood and machine learning techniques. We also discuss the
implications of the EFT for the next-generation (G2) direct detection
experiments and point out regions of complementarity in the EFT
parameter space.
Title: Maximum likelihood analysis of low energy CDMS II germanium
data
Authors: Agnese, R.; Anderson, A. J.; Balakishiyeva, D.; Basu Thakur,
R.; Bauer, D. A.; Billard, J.; Borgland, A.; Bowles, M. A.; Brandt,
D.; Brink, P. L.; Bunker, R.; Cabrera, B.; Caldwell, D. O.; Cerdeno,
D. G.; Chagani, H.; Chen, Y.; Cooley, J.; Cornell, B.; Crewdson, C. H.;
Cushman, P.; Daal, M.; Di Stefano, P. C. F.; Doughty, T.; Esteban,
L.; Fallows, S.; Figueroa-Feliciano, E.; Fritts, M.; Godfrey, G. L.;
Golwala, S. R.; Graham, M.; Hall, J.; Harris, H. R.; Hertel, S. A.;
Hofer, T.; Holmgren, D.; Hsu, L.; Huber, M. E.; Jastram, A.; Kamaev,
O.; Kara, B.; Kelsey, M. H.; Kennedy, A.; Kiveni, M.; Koch, K.; Leder,
A.; Loer, B.; Lopez Asamar, E.; Mahapatra, R.; Mandic, V.; Martinez,
C.; McCarthy, K. A.; Mirabolfathi, N.; Moffatt, R. A.; Moore, D. C.;
Nelson, R. H.; Oser, S. M.; Page, K.; Page, W. A.; Partridge, R.;
Pepin, M.; Phipps, A.; Prasad, K.; Pyle, M.; Qiu, H.; Rau, W.; Redl,
P.; Reisetter, A.; Ricci, Y.; Rogers, H. E.; Saab, T.; Sadoulet,
B.; Sander, J.; Schneck, K.; Schnee, R. W.; Scorza, S.; Serfass, B.;
Shank, B.; Speller, D.; Upadhyayula, S.; Villano, A. N.; Welliver,
B.; Wright, D. H.; Yellin, S.; Yen, J. J.; Young, B. A.; Zhang, J.;
SuperCDMS Collaboration
Bibcode: 2015PhRvD..91e2021A
Altcode: 2014arXiv1410.1003S
We report on the results of a search for a Weakly Interacting Massive
Particle (WIMP) signal in low-energy data of the Cryogenic Dark Matter
Search experiment using a maximum likelihood analysis. A background
model is constructed using geant4 to simulate the surface-event
background from 210Pb decay-chain events, while using
independent calibration data to model the gamma background. Fitting this
background model to the data results in no statistically significant
WIMP component. In addition, we perform fits using an analytic ad
hoc background model proposed by Collar and Fields, who claimed to
find a large excess of signal-like events in our data. We confirm
the strong preference for a signal hypothesis in their analysis
under these assumptions, but excesses are observed in both single-
and multiple-scatter events, which implies the signal is not caused
by WIMPs, but rather reflects the inadequacy of their background model.
Title: Dark Sky Collaborators: Arizona (AZ) Observatories,
Communities, and Businesses
Authors: Del Castillo, Elizabeth Alvarez; Corbally, Christopher; Falco,
Emilio E.; Green, Richard F.; Hall, Jeffrey C.; Williams, G. Grant
Bibcode: 2015HiA....16..747D
Altcode:
With outdoor lighting ordinances in Arizona first in place around
observatories in 1958 and 1972, then throughout the state since
1986, Arizonans have extensive experience working with communities
and businesses to preserve our dark skies. Though communities are
committed to the astronomy sector in our state, astronomers must
collaborate with other stakeholders to implement solutions. Ongoing
education and public outreach is necessary to enable ordinance updates
as technology changes. Despite significant population increases, sky
brightness measurements over the last 20 years show that ordinance
updates are worth our efforts as we seek to maintain high quality
skies around our observatories. Collaborations are being forged and
actions taken to promote astronomy for the longer term in Arizona.
Title: First Direct Limits on Lightly Ionizing Particles with Electric
Charge Less than e /6
Authors: Agnese, R.; Anderson, A. J.; Balakishiyeva, D.; Basu Thakur,
R.; Bauer, D. A.; Billard, J.; Borgland, A.; Bowles, M. A.; Brandt,
D.; Brink, P. L.; Bunker, R.; Cabrera, B.; Caldwell, D. O.; Cerdeno,
D. G.; Chagani, H.; Chen, Y.; Cooley, J.; Cornell, B.; Crewdson, C. H.;
Cushman, P.; Daal, M.; Di Stefano, P. C. F.; Doughty, T.; Esteban,
L.; Fallows, S.; Figueroa-Feliciano, E.; Godfrey, G. L.; Golwala,
S. R.; Hall, J.; Harris, H. R.; Hertel, S. A.; Hofer, T.; Holmgren,
D.; Hsu, L.; Huber, M. E.; Jastram, A.; Kamaev, O.; Kara, B.; Kelsey,
M. H.; Kennedy, A.; Kiveni, M.; Koch, K.; Leder, A.; Loer, B.; Lopez
Asamar, E.; Mahapatra, R.; Mandic, V.; Martinez, C.; McCarthy, K. A.;
Mirabolfathi, N.; Moffatt, R. A.; Moore, D. C.; Nelson, H.; Nelson,
R. H.; Ogburn, R. W.; Page, K.; Page, W. A.; Partridge, R.; Pepin,
M.; Phipps, A.; Prasad, K.; Pyle, M.; Qiu, H.; Rau, W.; Redl, P.;
Reisetter, A.; Ricci, Y.; Rogers, H. E.; Saab, T.; Sadoulet, B.;
Sander, J.; Schneck, K.; Schnee, R. W.; Scorza, S.; Serfass, B.;
Shank, B.; Speller, D.; Upadhyayula, S.; Villano, A. N.; Welliver,
B.; Wright, D. H.; Yellin, S.; Yen, J. J.; Young, B. A.; Zhang, J.;
CDMS Collaboration
Bibcode: 2015PhRvL.114k1302A
Altcode: 2014arXiv1409.3270A
While the standard model of particle physics does not include free
particles with fractional charge, experimental searches have not ruled
out their existence. We report results from the Cryogenic Dark Matter
Search (CDMS II) experiment that give the first direct-detection limits
for cosmogenically produced relativistic particles with electric charge
lower than e /6 . A search for tracks in the six stacked detectors
of each of two of the CDMS II towers finds no candidates, thereby
excluding new parameter space for particles with electric charges
between e /6 and e /200 .
Title: Bright Hot Jupiters: Phase Curves and Doppler Spectroscopy
Authors: Crossfield, Ian; Birkby, Jayne; Brogi, Matteo; Showman,
Adam; Krick, Jessica; Hansen, Brad; Hall, Jeffrey; Fortney, Jonathan;
Harrington, Joe; Heng, Kevin; Lopez-Morales, Mercedes; Cubillos,
Patricio; Snellen, Ignas; Cowan, Nick; Rodler, Florian; Benneke, Bjoern
Bibcode: 2014sptz.prop11044C
Altcode:
Exoplanet phase curves provide a wealth of information about
atmospheric dynamics, energetics, and chemistry. Phase curves have
been observed for relatively few planets, yet the current small sample
already hints at the inadequacy of current atmospheric models. Our
ultimate goal of understanding the global circulation patterns and
their relation to atmospheric chemistry requires a larger and more
homogenous sample. Here, we propose to more than double the sample of
hot Jupiters with high S/N phase observations by targeting seven bright
systems. Combined with the powerful new technique of high-resolution
infrared Doppler spectroscopy, our observations will enable an
unprecedented comparative study to relate global circulation patterns
to atmospheric chemistry, and ultimately to facilitate retrieval of
global abundance and temperature maps of extrasolar planets. The
planets in our sample represent the best objects to leverage both
space-based phase curves and ground-based spectroscopy in a combined
analysis. Spectroscopic observations break the inclination degeneracy
that plagued earlier non-transiting phase variations, while phase curves
provide crucial information about the planetary thermal continuum that
is lost in the inherently relative spectroscopic analysis. Our program
uses Spitzer's recently-validated snapshot-phase curve mode to obtain
high-precision photometry on long timescales with low data volumes
and high scheduling flexibility, and our new retrieval approach will
become a critical capability in an era of measurements at higher S/N
and spectral resolution with JWST and Extremely Large ground-based
telescopes.
Title: Erratum: First dark matter search results from a 4-kg
CF3I bubble chamber operated in a deep underground site
[Phys. Rev. D 86, 052001 (2012)]
Authors: Behnke, E.; Behnke, J.; Brice, S. J.; Broemmelsiek, D.;
Collar, J. I.; Conner, A.; Cooper, P. S.; Crisler, M.; Dahl, C. E.;
Fustin, D.; Grace, E.; Hall, J.; Hu, M.; Levine, I.; Lippincott, W. H.;
Moan, T.; Nania, T.; Ramberg, E.; Robinson, A. E.; Sonnenschein, A.;
Szydagis, M.; Vázquez-Jáuregui, E.; Coupp Collaboration
Bibcode: 2014PhRvD..90g9902B
Altcode:
No abstract at ADS
Title: Flexible Cover Glass for Next Generation Solar Arrays
Authors: Gray, D. A.; Hall, J.; Jones, G. M.
Bibcode: 2014ESASP.719E..73G
Altcode:
The prospect of thin, flexible, high-efficiency solar cells has raised
questions about how to integrate and protect them, especially on a
flexible array substrate. Although these next-generation cells are still
subject to development, it seems likely that some form of protection
against radiation and atomic oxygen will be required. It is possible
that chemically toughened coverglasses could fulfil this requirement;
however a better understanding of glass strength and static fatigue
properties is needed in order to evaluate this solution in all phases
of operation. This paper aims to discuss the issues and present the
results of experimental work to date.
Title: Search for Low-Mass Weakly Interacting Massive Particles
with SuperCDMS
Authors: Agnese, R.; Anderson, A. J.; Asai, M.; Balakishiyeva, D.;
Basu Thakur, R.; Bauer, D. A.; Beaty, J.; Billard, J.; Borgland,
A.; Bowles, M. A.; Brandt, D.; Brink, P. L.; Bunker, R.; Cabrera,
B.; Caldwell, D. O.; Cerdeno, D. G.; Chagani, H.; Chen, Y.; Cherry,
M.; Cooley, J.; Cornell, B.; Crewdson, C. H.; Cushman, P.; Daal, M.;
DeVaney, D.; Di Stefano, P. C. F.; Silva, E. Do Couto E.; Doughty,
T.; Esteban, L.; Fallows, S.; Figueroa-Feliciano, E.; Godfrey, G. L.;
Golwala, S. R.; Hall, J.; Hansen, S.; Harris, H. R.; Hertel, S. A.;
Hines, B. A.; Hofer, T.; Holmgren, D.; Hsu, L.; Huber, M. E.; Jastram,
A.; Kamaev, O.; Kara, B.; Kelsey, M. H.; Kenany, S.; Kennedy, A.;
Kiveni, M.; Koch, K.; Leder, A.; Loer, B.; Lopez Asamar, E.; Mahapatra,
R.; Mandic, V.; Martinez, C.; McCarthy, K. A.; Mirabolfathi, N.;
Moffatt, R. A.; Nelson, R. H.; Novak, L.; Page, K.; Partridge, R.;
Pepin, M.; Phipps, A.; Platt, M.; Prasad, K.; Pyle, M.; Qiu, H.; Rau,
W.; Redl, P.; Reisetter, A.; Resch, R. W.; Ricci, Y.; Ruschman, M.;
Saab, T.; Sadoulet, B.; Sander, J.; Schmitt, R. L.; Schneck, K.;
Schnee, R. W.; Scorza, S.; Seitz, D. N.; Serfass, B.; Shank, B.;
Speller, D.; Tomada, A.; Upadhyayula, S.; Villano, A. N.; Welliver,
B.; Wright, D. H.; Yellin, S.; Yen, J. J.; Young, B. A.; Zhang, J.;
SuperCDMS Collaboration
Bibcode: 2014PhRvL.112x1302A
Altcode: 2014arXiv1402.7137A
We report a first search for weakly interacting massive particles
(WIMPs) using the background rejection capabilities of SuperCDMS. An
exposure of 577 kg days was analyzed for WIMPs with mass <30
GeV/c2, with the signal region blinded. Eleven events were
observed after unblinding. We set an upper limit on the spin-independent
WIMP-nucleon cross section of 1.2×10-42 cm2 at 8 GeV
/c2. This result is in tension with WIMP interpretations
of recent experiments and probes new parameter space for WIMP-nucleon
scattering for WIMP masses <6 GeV /c2.
Title: Recent Local and State Action in Arizona to Maintain Sky
Quality
Authors: Hall, Jeffrey C.; Shankland, P. D.; Green, R. F.; Jannuzi, B.
Bibcode: 2014AAS...22341306H
Altcode:
The large number of observatories in Arizona has led to the development
of a number of lighting control ordinances around the state, some quite
strict. Several factors are now contributing to an increased need for
active effort at the local, County, and State levels in maintaining
the quality of these codes; these factors include an expansion of
competing interests in the state, the increasing use of LED lighting,
and the potential for major new investments through projects such
as the Cherenkov Telescope Array (CTA) and enhancements to the Navy
Precision Optical Interferometer. I will review recent strategies
Arizona's observatories have used to effect maintenance of ordinances
and preserve sky quality; cases include (1) a statewide effort in 2012
to curb a proliferation of electronic billboards and (2) engagement
of a broad group of local, County, and State officials, as well as
individuals from the private sector, in support of projects like CTA,
including awareness of and support for dark-sky preservation.
Title: Progress in Dark Sky Protection in Southern Arizona
Authors: Green, Richard F.; Allen, L.; Alvarez Del Castillo, E. M.;
Brocious, D. K.; Corbally, C. J.; Davis, D. R.; Falco, E. E.; Gabor,
P.; Hall, J. C.; Jannuzi, B.; Larson, S. M.; Mighell, K. J.; Nance,
C.; Shankland, P. D.; Walker, C. E.; Williams, G.; Zaritsky, D. F.
Bibcode: 2014AAS...22341305G
Altcode:
Arizona has many observatories dedicated to scientific research
and a rapidly growing population. Continuous interaction with
governmental entities and education of the public are required to
take advantage of the good intentions of lighting control ordinances
in place around the state. We give several recent examples of active
engagement of observatories: * Interaction of Mt. Graham International
Observatory with the State prison and major copper mine. * Interaction
of Smithsonian Astrophysical Observatory, acting on behalf of MMT
Observatory and Steward Observatory, with the US Forest Service on
the prospects of developing the Rosemont Copper Mine * Defense of the
Outdoor Lighting and Sign Codes in Pima County and the City of Tucson
* Coordinated observatory approach to statewide issues, including the
establishment of radial zones of protection from LED billboards around
observatory sites.
Title: Search for Low-Mass Weakly Interacting Massive Particles
Using Voltage-Assisted Calorimetric Ionization Detection in the
SuperCDMS Experiment
Authors: Agnese, R.; Anderson, A. J.; Asai, M.; Balakishiyeva, D.; Basu
Thakur, R.; Bauer, D. A.; Billard, J.; Borgland, A.; Bowles, M. A.;
Brandt, D.; Brink, P. L.; Bunker, R.; Cabrera, B.; Caldwell, D. O.;
Cerdeno, D. G.; Chagani, H.; Cooley, J.; Cornell, B.; Crewdson, C. H.;
Cushman, P.; Daal, M.; Di Stefano, P. C. F.; Doughty, T.; Esteban,
L.; Fallows, S.; Figueroa-Feliciano, E.; Godfrey, G. L.; Golwala,
S. R.; Hall, J.; Harris, H. R.; Hertel, S. A.; Hofer, T.; Holmgren,
D.; Hsu, L.; Huber, M. E.; Jastram, A.; Kamaev, O.; Kara, B.; Kelsey,
M. H.; Kennedy, A.; Kiveni, M.; Koch, K.; Loer, B.; Lopez Asamar, E.;
Mahapatra, R.; Mandic, V.; Martinez, C.; McCarthy, K. A.; Mirabolfathi,
N.; Moffatt, R. A.; Moore, D. C.; Nadeau, P.; Nelson, R. H.; Page, K.;
Partridge, R.; Pepin, M.; Phipps, A.; Prasad, K.; Pyle, M.; Qiu, H.;
Rau, W.; Redl, P.; Reisetter, A.; Ricci, Y.; Saab, T.; Sadoulet, B.;
Sander, J.; Schneck, K.; Schnee, R. W.; Scorza, S.; Serfass, B.; Shank,
B.; Speller, D.; Villano, A. N.; Welliver, B.; Wright, D. H.; Yellin,
S.; Yen, J. J.; Young, B. A.; Zhang, J.; SuperCDMS Collaboration
Bibcode: 2014PhRvL.112d1302A
Altcode: 2013arXiv1309.3259A
SuperCDMS is an experiment designed to directly detect weakly
interacting massive particles (WIMPs), a favored candidate for
dark matter ubiquitous in the Universe. In this Letter, we present
WIMP-search results using a calorimetric technique we call CDMSlite,
which relies on voltage-assisted Luke-Neganov amplification of the
ionization energy deposited by particle interactions. The data were
collected with a single 0.6 kg germanium detector running for ten live
days at the Soudan Underground Laboratory. A low energy threshold
of 170 eVee (electron equivalent) was obtained, which allows us to
constrain new WIMP-nucleon spin-independent parameter space for WIMP
masses below 6 GeV /c2.
Title: The Navy Precision Optical Interferometer (npoi): AN Update
Authors: Armstrong, J. T.; Hutter, D. J.; Baines, E. K.; Benson,
J. A.; Bevilacqua, R. M.; Buschmann, T.; Clark, J. H.; Ghasempour,
A.; Hall, J. C.; Hindsley, R. B.; Johnston, K. J.; Jorgensen, A. M.;
Mozurkewich, D.; Muterspaugh, M. W.; Restaino, S. R.; Shankland,
P. D.; Schmitt, H. R.; Tycner, C.; van Belle, G. T.; Zavala, R. T.
Bibcode: 2013JAI.....240002A
Altcode:
The Navy Precision Optical Interferometer (NPOI) has two purposes:
wide angle precise astrometry and high-resolution imaging, both at
visible wavelengths. It operates with up to six 12-cm diameter apertures
simultaneously, with baseline lengths (distances between array elements)
from 16 m to 79 m, and disperses the combined light into 16 spectral
channels. It has been operational since first fringes were found in
1994; six-beam operations began in 2001. The NPOI is undergoing upgrades
in numerous areas: control system and data acquisition improvements,
a second beam combiner, additional array stations for both longer
and shorter baselines, and supplemental delay lines to improve sky
coverage for the longer baselines. Future possibilities include the
installation of four fixed 1.8 m telescopes as well as up to six
moveable lightweight 1.4 m telescopes. Observing programs, including
programs led by outside investigators, cover a broad range of stellar
astrophysics as well as observations of geostationary satellites.
Title: Silicon Detector Dark Matter Results from the Final Exposure
of CDMS II
Authors: Agnese, R.; Ahmed, Z.; Anderson, A. J.; Arrenberg, S.;
Balakishiyeva, D.; Basu Thakur, R.; Bauer, D. A.; Billard, J.;
Borgland, A.; Brandt, D.; Brink, P. L.; Bruch, T.; Bunker, R.;
Cabrera, B.; Caldwell, D. O.; Cerdeno, D. G.; Chagani, H.; Cooley,
J.; Cornell, B.; Crewdson, C. H.; Cushman, P.; Daal, M.; Dejongh,
F.; do Couto e Silva, E.; Doughty, T.; Esteban, L.; Fallows, S.;
Figueroa-Feliciano, E.; Filippini, J.; Fox, J.; Fritts, M.; Godfrey,
G. L.; Golwala, S. R.; Hall, J.; Harris, R. H.; Hertel, S. A.; Hofer,
T.; Holmgren, D.; Hsu, L.; Huber, M. E.; Jastram, A.; Kamaev, O.;
Kara, B.; Kelsey, M. H.; Kennedy, A.; Kim, P.; Kiveni, M.; Koch, K.;
Kos, M.; Leman, S. W.; Loer, B.; Lopez Asamar, E.; Mahapatra, R.;
Mandic, V.; Martinez, C.; McCarthy, K. A.; Mirabolfathi, N.; Moffatt,
R. A.; Moore, D. C.; Nadeau, P.; Nelson, R. H.; Page, K.; Partridge,
R.; Pepin, M.; Phipps, A.; Prasad, K.; Pyle, M.; Qiu, H.; Rau, W.;
Redl, P.; Reisetter, A.; Ricci, Y.; Saab, T.; Sadoulet, B.; Sander,
J.; Schneck, K.; Schnee, R. W.; Scorza, S.; Serfass, B.; Shank, B.;
Speller, D.; Sundqvist, K. M.; Villano, A. N.; Welliver, B.; Wright,
D. H.; Yellin, S.; Yen, J. J.; Yoo, J.; Young, B. A.; Zhang, J.
Bibcode: 2013PhRvL.111y1301A
Altcode:
We report results of a search for weakly interacting massive
particles (WIMPS) with the silicon detectors of the CDMS
II experiment. This blind analysis of 140.2 kg day of data
taken between July 2007 and September 2008 revealed three
WIMP-candidate events with a surface-event background estimate of
0.41-0.08+0.20(stat)-0.24+0.28(syst).
Other known backgrounds from neutrons and Pb206 are limited to <0.13
and <0.08 events at the 90% confidence level, respectively. The
exposure of this analysis is equivalent to 23.4 kg day for a recoil
energy range of 7-100 keV for a WIMP of mass 10GeV/c2. The
probability that the known backgrounds would produce three or more
events in the signal region is 5.4%. A profile likelihood ratio
test of the three events that includes the measured recoil energies
gives a 0.19% probability for the known-background-only hypothesis
when tested against the alternative WIMP+background hypothesis. The
highest likelihood occurs for a WIMP mass of 8.6GeV/c2
and WIMP-nucleon cross section of 1.9×10-41cm2.
Title: A Homogeneous Phase Curve Sample for Global Atmospheric
Retrieval
Authors: Crossfield, Ian; Cowan, Nicolas; Snellen, Ignas; Showman,
Adam; Brogi, Matteo; Birkby, Jayne; Heng, Kevin; Harrington, Joseph;
Fortney, Jonathan; Rodler, Florian; Hansen, Brad; Hall, Jeffrey;
Lopez-Morales, Mercedes; Cubillos, Patricio; Benneke, Bjoern
Bibcode: 2013sptz.prop10078C
Altcode:
Exoplanet phase curves provide a wealth of information about atmospheric
dynamics, energetics, and chemistry. Phase curves have been observed
for relatively few planets, yet the current small sample already hints
at the inadequacy of current atmospheric models. Our ultimate goal
of understanding the global circulation patterns and their relation
to atmospheric chemistry requires a larger and more homogenous
sample. Here, we propose to more than double the sample of hot
Jupiters with high S/N phase observations by targeting five bright
non-transiting systems. Combined with the powerful new technique
of high-resolution infrared Doppler spectroscopy, our observations
will enable an unprecedented comparative study to relate global
circulation patterns and atmospheric chemistry, and ultimately
facilitate retrieval of the first global abundance and temperature
maps of extrasolar planets. The planets in our sample represent the
best objects to leverage both space-based phase curves and ground-based
spectroscopy in a combined analysis. Spectroscopic observations break
the inclination degeneracy that plagued earlier non-transiting phase
variations, while phase curves provide crucial information about the
planetary thermal continuum that is lost in the inherently relative
spectroscopic analysis. Our program uses Spitzer's recently-validated
observing mode to obtain high-precision photometry on long timescales
with low data volumes and high scheduling flexibility, and our new
retrieval approach will become a critical capability in an era of
measurements at higher S/N and spectral resolution with JWST and
Extremely Large ground-based telescopes.
Title: Snowmass CF1 Summary: WIMP Dark Matter Direct Detection
Authors: Cushman, P.; Galbiati, C.; McKinsey, D. N.; Robertson, H.;
Tait, T. M. P.; Bauer, D.; Borgland, A.; Cabrera, B.; Calaprice, F.;
Cooley, J.; Empl, T.; Essig, R.; Figueroa-Feliciano, E.; Gaitskell,
R.; Golwala, S.; Hall, J.; Hill, R.; Hime, A.; Hoppe, E.; Hsu, L.;
Hungerford, E.; Jacobsen, R.; Kelsey, M.; Lang, R. F.; Lippincott,
W. H.; Loer, B.; Luitz, S.; Mandic, V.; Mardon, J.; Maricic, J.;
Maruyama, R.; Mahapatra, R.; Nelson, H.; Orrell, J.; Palladino, K.;
Pantic, E.; Partridge, R.; Ryd, A.; Saab, T.; Sadoulet, B.; Schnee, R.;
Shepherd, W.; Sonnenschein, A.; Sorensen, P.; Szydagis, M.; Volansky,
T.; Witherell, M.; Wright, D.; Zurek, K.
Bibcode: 2013arXiv1310.8327C
Altcode:
As part of the Snowmass process, the Cosmic Frontier WIMP Direct
Detection subgroup (CF1) has drawn on input from the Cosmic Frontier and
the broader Particle Physics community to produce this document. The
charge to CF1 was (a) to summarize the current status and projected
sensitivity of WIMP direct detection experiments worldwide, (b) motivate
WIMP dark matter searches over a broad parameter space by examining
a spectrum of WIMP models, (c) establish a community consensus on the
type of experimental program required to explore that parameter space,
and (d) identify the common infrastructure required to practically
meet those goals.
Title: Computational Challenges in Processing the Q1-Q16 Kepler
Data Set
Authors: Klaus, Todd C.; Henze, C.; Twicken, J. D.; Hall, J.;
McCauliff, S. D.; Girouard, F.; Cote, M.; Morris, R. L.; Clarke, B.;
Jenkins, J. M.; Caldwell, D.; Kepler Science Operations Center
Bibcode: 2013DPS....4520907K
Altcode:
Since launch on March 6th, 2009, NASA’s Kepler Space Telescope has
collected 48 months of data on over 195,000 targets. The raw data are
rife with instrumental and astrophysical noise that must be removed
in order to detect and model the transit-like signals present in the
data. Calibrating the raw pixels, generating and correcting the flux
light curves, and detecting and characterizing the signals require
significant computational power. In addition, the algorithms that
make up the Kepler Science Pipeline and their parameters are still
undergoing changes (most of which increase the computational cost),
creating the need to reprocess the entire data set on a regular
basis. We discuss how we have ported all of the core elements of the
pipeline to the Pleiades cluster at the NASA Advanced Supercomputing
(NAS) Division, the needs driving the port, and the technical challenges
we faced. In 2011 we ported the Transiting Planet Search (TPS) and Data
Validation (DV) modules to Pleiades. These pipeline modules operate on
the full data set and the computational complexity increases roughly
by the square of the number of data points. At the time of the port
it had become infeasible to run these modules on our local hardware,
necessitating the move to Pleiades. In 2012 and 2013 we turned our
attention to the front end of the pipeline; Pixel-level Calibration
(CAL), Photometric Analysis (PA), and Pre-Search Data Conditioning
(PDC). Porting these modules to Pleiades will allow us to reprocess the
complete data set on a more frequent basis. The last time we reprocessed
all data for the front end we only had 24 months of data. We estimate
that the full 48-month data set would take over 200 days to complete
on local hardware. When the port is complete we expect to reprocess
this data set on Pleiades in about a month. The NASA Science Mission
Directorate provided funding for the Kepler Mission.
Title: Publisher's Note: Silicon detector results from the first
five-tower run of CDMS II [Phys. Rev. D 88, 031104(R) (2013)]
Authors: Agnese, R.; Ahmed, Z.; Anderson, A. J.; Arrenberg, S.;
Balakishiyeva, D.; Basu Thakur, R.; Bauer, D. A.; Borgland, A.;
Brandt, D.; Brink, P. L.; Bruch, T.; Bunker, R.; Cabrera, B.;
Caldwell, D. O.; Cerdeno, D. G.; Chagani, H.; Cooley, J.; Cornell,
B.; Crewdson, C. H.; Cushman, P.; Daal, M.; Dejongh, F.; Di Stefano,
P. C. F.; do Couto e Silva, E.; Doughty, T.; Esteban, L.; Fallows,
S.; Figueroa-Feliciano, E.; Filippini, J.; Fox, J.; Fritts, M.;
Godfrey, G. L.; Golwala, S. R.; Hall, J.; Harris, R. H.; Hertel,
S. A.; Hofer, T.; Holmgren, D.; Hsu, L.; Huber, M. E.; Jastram, A.;
Kamaev, O.; Kara, B.; Kelsey, M. H.; Kennedy, A.; Kim, P.; Kiveni,
M.; Koch, K.; Kos, M.; Leman, S. W.; Lopez-Asamar, E.; Mahapatra, R.;
Mandic, V.; Martinez, C.; McCarthy, K. A.; Mirabolfathi, N.; Moffatt,
R. A.; Moore, D. C.; Nadeau, P.; Nelson, R. H.; Page, K.; Partridge,
R.; Pepin, M.; Phipps, A.; Prasad, K.; Pyle, M.; Qiu, H.; Rau, W.;
Redl, P.; Reisetter, A.; Ricci, Y.; Saab, T.; Sadoulet, B.; Sander,
J.; Schneck, K.; Schnee, R. W.; Scorza, S.; Serfass, B.; Shank, B.;
Speller, D.; Sundqvist, K. M.; Villano, A. N.; Welliver, B.; Wright,
D. H.; Yellin, S.; Yen, J. J.; Yoo, J.; Young, B. A.; Zhang, J.
Bibcode: 2013PhRvD..88e9901A
Altcode:
No abstract at ADS
Title: Silicon detector results from the first five-tower run of
CDMS II
Authors: Agnese, R.; Ahmed, Z.; Anderson, A. J.; Arrenberg, S.;
Balakishiyeva, D.; Basu Thakur, R.; Bauer, D. A.; Borgland, A.;
Brandt, D.; Brink, P. L.; Bruch, T.; Bunker, R.; Cabrera, B.;
Caldwell, D. O.; Cerdeno, D. G.; Chagani, H.; Cooley, J.; Cornell,
B.; Crewdson, C. H.; Cushman, P.; Daal, M.; Dejongh, F.; Di tefano,
P. C. F.; do Couto e Silva, E.; Doughty, T.; Esteban, L.; Fallows,
S.; Figueroa-Feliciano, E.; Filippini, J.; Fox, J.; Fritts, M.;
Godfrey, G. L.; Golwala, S. R.; Hall, J.; Harris, R. H.; Hertel,
S. A.; Hofer, T.; Holmgren, D.; Hsu, L.; Huber, M. E.; Jastram, A.;
Kamaev, O.; Kara, B.; Kelsey, M. H.; Kennedy, A.; Kim, P.; Kiveni,
M.; Koch, K.; Kos, M.; Leman, S. W.; Lopez-Asamar, E.; Mahapatra, R.;
Mandic, V.; Martinez, C.; McCarthy, K. A.; Mirabolfathi, N.; Moffatt,
R. A.; Moore, D. C.; Nadeau, P.; Nelson, R. H.; Page, K.; Partridge,
R.; Pepin, M.; Phipps, A.; Prasad, K.; Pyle, M.; Qiu, H.; Rau, W.;
Redl, P.; Reisetter, A.; Ricci, Y.; Saab, T.; Sadoulet, B.; Sander,
J.; Schneck, K.; Schnee, R. W.; Scorza, S.; Serfass, B.; Shank, B.;
Speller, D.; Sundqvist, K. M.; Villano, A. N.; Welliver, B.; Wright,
D. H.; Yellin, S.; Yen, J. J.; Yoo, J.; Young, B. A.; Zhang, J.
Bibcode: 2013PhRvD..88c1104A
Altcode: 2013arXiv1304.3706C
We report results of a search for weakly interacting massive particles
(WIMPs) with the Si detectors of the CDMS II experiment. This
report describes a blind analysis of the first data taken with CDMS
II’s full complement of detectors in 2006-2007; results from this
exposure using the Ge detectors have already been presented. We
observed no candidate WIMP-scattering events in an exposure of 55.9
kg-days before analysis cuts, with an expected background of ∼1.1
events. The exposure of this analysis is equivalent to 10.3 kg-days
over a recoil energy range of 7-100 keV for an ideal Si detector
and a WIMP mass of 10GeV/c2. These data set an upper
limit of 1.7×10-41cm2 on the WIMP-nucleon
spin-independent cross section of a 10GeV/c2 WIMP. These
data exclude parameter space for spin-independent WIMP-nucleon elastic
scattering that is relevant to recent searches for low-mass WIMPs.
Title: Direct measurement of the bubble-nucleation energy threshold
in a CF3I bubble chamber
Authors: Behnke, E.; Benjamin, T.; Brice, S. J.; Broemmelsiek, D.;
Collar, J. I.; Cooper, P. S.; Crisler, M.; Dahl, C. E.; Fustin,
D.; Hall, J.; Harnish, C.; Levine, I.; Lippincott, W. H.; Moan, T.;
Nania, T.; Neilson, R.; Ramberg, E.; Robinson, A. E.; Ruschman, M.;
Sonnenschein, A.; Vázquez-Jáuregui, E.; Rivera, R. A.; Uplegger, L.
Bibcode: 2013PhRvD..88b1101B
Altcode: 2013arXiv1304.6001C
We have directly measured the energy threshold and efficiency for
bubble nucleation from iodine recoils in a CF3I bubble
chamber in the energy range of interest for a dark matter search. These
interactions cannot be probed by standard neutron calibration methods,
so we develop a new technique by observing the elastic scattering of
12GeV/c negative pions. The pions are tracked with a silicon pixel
telescope and the reconstructed scattering angle provides a measure
of the nuclear recoil kinetic energy. The bubble chamber was operated
with a nominal threshold of (13.6±0.6)keV. Interpretation of the
results depends on the response to fluorine and carbon recoils, but
in general we find agreement with the predictions of the classical
bubble-nucleation theory. This measurement confirms the applicability
of CF3I as a target for spin-independent dark matter
interactions and represents a novel technique for calibration of
superheated fluid detectors.
Title: 2013 KN6
Authors: Scotti, J. V.; Stevens, B. L.; Boattini, A.; Christensen,
E. J.; Gibbs, A. R.; Grauer, A. D.; Hill, R. E.; Johnson, J. A.;
Kowalski, R. A.; Larson, S. M.; McNaught, R. H.; Shelly, F. C.;
Wiggins, P.; McGaha, J. E.; Diaz, N. D.; Aymami, J. M.; Camarasa, J.;
Bosch, J. M.; Aixela, G.; Bosque, R.; Rodriguez, D.; Diepvens, A.;
Jahn, J.; Zolnowski, M.; Kusiak, M.; Kurtze, L.; Hidas, A.; Pritchett,
N. E.; Mills, M.; Urbanik, M.; Guido, E.; Howes, N.; Hall, J.; Holmes,
R.; Foglia, S.; Buzzi, L.; Devore, H.; Kostin, A.; Linder, T.; Lister,
T.; Vorobjov, T.; Chapman, A.; Jacques, C.; Pimentel, E.; Losse, F.;
Carreno, A.; Piqueras, J.; Briggs, D.; Viano, E.; Sato, H.; Shaheen,
W.; Viscome, G.; Colazo, C.; Melia, R.; Aznar, A.
Bibcode: 2013MPEC....L...09S
Altcode:
No abstract at ADS
Title: SuperCDMS status from Soudan and plans for SNOLab
Authors: Sander, J.; Ahmed, Z.; Anderson, A. J.; Arrenberg, S.;
Balakishiyeva, D.; Thakur, R. B.; Bauer, D. A.; Brandt, D.; Brink,
P. L.; Bunker, R.; Cabrera, B.; Caldwell, D. O.; Cerdeno, D. G.;
Chagani, H.; Cooley, J.; Cornell, B.; Crewdson, C. H.; Cushman, P.;
Daal, M.; Di Stefano, P. C. F.; Silva, E. Do Couto E.; Doughty, T.;
Esteban, L.; Fallows, S.; Figueroa-Feliciano, E.; Fox, J.; Fritts,
M.; Godfrey, G. L.; Golwala, S. R.; Hall, J.; Hasi, J.; Hertel,
S. A.; Hofer, T.; Holmgren, D.; Hsu, L.; Huber, M. E.; Jastram, A.;
Kamaev, O.; Kara, B.; Kelsey, M. H.; Kim, P.; Kiveni, M.; Koch, K.;
Kos, M.; Leman, S. W.; Liu, S.; Loer, B.; Mahapatra, R.; Mandic, V.;
Martinez, C.; Mccarthy, K. A.; Mirabolfathi, N.; Moffat, R.; Moore,
D. C.; Nadeau, P.; Nelson, R.; Page, K.; Partridge, R.; Pepin, M.;
Phipps, A.; Prasad, K.; Pyle, M.; Qiu, H.; Qiu, X.; Radpour, R.;
Rau, W.; Reisetter, A.; Resch, R. W.; Ricci, Y.; Saab, T.; Sadoulet,
B.; Schnee, R. W.; Scorza, S.; Serfass, B.; Shank, B.; Shneck, K.;
Speller, D.; Sundqvist, K. M.; Villano, A. N.; Welliver, B.; Yellin,
S.; Yen, J.; Yoo, J.; Young, B. A.; Zhang, J.
Bibcode: 2013AIPC.1534..129S
Altcode:
Matter, as we know it, makes up less than 5% of the Universe. Various
astrophysical observations have confirmed that one quarter of the
Universe and most of the matter content in the Universe is made up
of Dark Matter. The nature of Dark Matter is yet to be discovered
and is one of the biggest questions in Physics. Particle Physics
combined with astrophysical measurements of the abundance gives rise
to a Dark Matter candidate called Weakly Interacting Massive Particle
(WIMP). The low density of WIMPs in the galaxies and the extremely
weak nature of the interaction with ordinary matter make detection
of the WIMP an extraordinarily challenging task, with abundant fakes
from various radioactive and cosmogenic backgrounds with much stronger
electromagnetic interaction. The extremely weak nature of the WIMP
interaction dictates detectors that have extremely low naturally
occurring radioactive background, a large active volume (mass) of
sensitive detector material to maximize statistics, a highly efficient
detector based rejection mechanism for the dominant electromagnetic
background and sophisticated analysis techniques to reject any residual
background. This paper describes the status of the SuperCDMS experiment.
Title: The Pulsar Search Collaboratory: Discovery and Timing of Five
New Pulsars
Authors: Rosen, R.; Swiggum, J.; McLaughlin, M. A.; Lorimer, D. R.;
Yun, M.; Heatherly, S. A.; Boyles, J.; Lynch, R.; Kondratiev, V. I.;
Scoles, S.; Ransom, S. M.; Moniot, M. L.; Cottrill, A.; Weaver, M.;
Snider, A.; Thompson, C.; Raycraft, M.; Dudenhoefer, J.; Allphin, L.;
Thorley, J.; Meadows, B.; Marchiny, G.; Liska, A.; O'Dwyer, A. M.;
Butler, B.; Bloxton, S.; Mabry, H.; Abate, H.; Boothe, J.; Pritt, S.;
Alberth, J.; Green, A.; Crowley, R. J.; Agee, A.; Nagley, S.; Sargent,
N.; Hinson, E.; Smith, K.; McNeely, R.; Quigley, H.; Pennington,
A.; Chen, S.; Maynard, T.; Loope, L.; Bielski, N.; McGough, J. R.;
Gural, J. C.; Colvin, S.; Tso, S.; Ewen, Z.; Zhang, M.; Ciccarella,
N.; Bukowski, B.; Novotny, C. B.; Gore, J.; Sarver, K.; Johnson, S.;
Cunningham, H.; Collins, D.; Gardner, D.; Monteleone, A.; Hall, J.;
Schweinhagen, R.; Ayers, J.; Jay, S.; Uosseph, B.; Dunkum, D.; Pal,
J.; Dydiw, S.; Sterling, M.; Phan, E.
Bibcode: 2013ApJ...768...85R
Altcode: 2012arXiv1209.4108R
We present the discovery and timing solutions of five new pulsars by
students involved in the Pulsar Search Collaboratory, a NSF-funded
joint program between the National Radio Astronomy Observatory and
West Virginia University designed to excite and engage high-school
students in Science, Technology, Engineering, and Mathematics (STEM)
and related fields. We encourage students to pursue STEM fields by
apprenticing them within a professional scientific community doing
cutting edge research, specifically by teaching them to search for
pulsars. The students are analyzing 300 hr of drift-scan survey data
taken with the Green Bank Telescope at 350 MHz. These data cover 2876
deg2 of the sky. Over the course of five years, more than 700
students have inspected diagnostic plots through a web-based graphical
interface designed for this project. The five pulsars discovered in
the data have spin periods ranging from 3.1 ms to 4.8 s. Among the
new discoveries are PSR J1926-1314, a long period, nulling pulsar;
PSR J1821+0155, an isolated, partially recycled 33 ms pulsar; and PSR
J1400-1438, a millisecond pulsar in a 9.5 day orbit whose companion
is likely a white dwarf star.
Title: Silicon Detector Dark Matter Results from the Final Exposure
of CDMS II
Authors: CDMS Collaboration; Agnese, R.; Ahmed, Z.; Anderson, A. J.;
Arrenberg, S.; Balakishiyeva, D.; Basu Thakur, R.; Bauer, D. A.;
Billard, J.; Borgland, A.; Brandt, D.; Brink, P. L.; Bruch, T.; Bunker,
R.; Cabrera, B.; Caldwell, D. O.; Cerdeno, D. G.; Chagani, H.; Cooley,
J.; Cornell, B.; Crewdson, C. H.; Cushman, P.; Daal, M.; Dejongh,
F.; Silva, E. Do Couto E; Doughty, T.; Esteban, L.; Fallows, S.;
Figueroa-Feliciano, E.; Filippini, J.; Fox, J.; Fritts, M.; Godfrey,
G. L.; Golwala, S. R.; Hall, J.; Harris, R. H.; Hertel, S. A.; Hofer,
T.; Holmgren, D.; Hsu, L.; Huber, M. E.; Jastram, A.; Kamaev, O.;
Kara, B.; Kelsey, M. H.; Kennedy, A.; Kim, P.; Kiveni, M.; Koch, K.;
Kos, M.; Leman, S. W.; Loer, B.; Lopez Asamar, E.; Mahapatra, R.;
Mandic, V.; Martinez, C.; McCarthy, K. A.; Mirabolfathi, N.; Moffatt,
R. A.; Moore, D. C.; Nadeau, P.; Nelson, R. H.; Page, K.; Partridge,
R.; Pepin, M.; Phipps, A.; Prasad, K.; Pyle, M.; Qiu, H.; Rau, W.;
Redl, P.; Reisetter, A.; Ricci, Y.; Saab, T.; Sadoulet, B.; Sander,
J.; Schneck, K.; Schnee, R. W.; Scorza, S.; Serfass, B.; Shank, B.;
Speller, D.; Sundqvist, K. M.; Villano, A. N.; Welliver, B.; Wright,
D. H.; Yellin, S.; Yen, J. J.; Yoo, J.; Young, B. A.; Zhang, J.
Bibcode: 2013arXiv1304.4279C
Altcode:
We report results of a search for Weakly Interacting Massive
Particles (WIMPS) with the silicon detectors of the CDMS II
experiment. This blind analysis of 140.2 kg-days of data
taken between July 2007 and September 2008 revealed three
WIMP-candidate events with a surface-event background estimate of
0.41^{+0.20}_{-0.08}(stat.)^{+0.28}_{-0.24}(syst.). Other known
backgrounds from neutrons and 206Pb are limited to < 0.13 and
<0.08 events at the 90% confidence level, respectively. The exposure
of this analysis is equivalent to 23.4 kg-days for a recoil energy
range of 7-100 keV for a WIMP of mass 10 GeV/c2. The probability that
the known backgrounds would produce three or more events in the signal
region is 5.4%. A profile likelihood ratio test of the three events that
includes the measured recoil energies gives a 0.19% probability for the
known-background-only hypothesis when tested against the alternative
WIMP+background hypothesis. The highest likelihood occurs for a WIMP
mass of 8.6 GeV/c2 and WIMP-nucleon cross section of 1.9e-41 cm2.
Title: Decadal Variations of Sun-Like Stars
Authors: Lockwood, G. W.; Henry, G. W.; Hall, J. C.; Radick, R. R.
Bibcode: 2013ASPC..472..203L
Altcode:
Observations of more than 300 Sun-like field stars carried out
at Fairborn Observatory since 1993 now include 168 observed for 10
years or longer. This project, a successor to previous work at Lowell
Observatory and Cloudcroft Observatory, beginning in 1955 and continuing
for nearly half a century, demonstrates finally that variability at
the Sun's low level of total irradiance variation can be detected in
stars. By also including Ca II H&K observations from the Mount
Wilson and Lowell observatories, we have discovered how the patterns
of photometric variability are related to chromospheric activity. We
discuss the limitations of detectability imposed by comparison star
variability and as an example of a star close to the detection limit
we show the evidence for cyclic variability in the solar twin 18 Sco.
Title: Magnetic Activity Cycles in the Exoplanet Host Star epsilon
Eridani
Authors: Metcalfe, T. S.; Buccino, A. P.; Brown, B. P.; Mathur, S.;
Soderblom, D. R.; Henry, T. J.; Mauas, P. J. D.; Petrucci, R.; Hall,
J. C.; Basu, S.
Bibcode: 2013ApJ...763L..26M
Altcode: 2012arXiv1212.4425M
The active K2 dwarf epsilon Eri has been extensively characterized
both as a young solar analog and more recently as an exoplanet host
star. As one of the nearest and brightest stars in the sky, it provides
an unparalleled opportunity to constrain stellar dynamo theory beyond
the Sun. We confirm and document the 3-year magnetic activity cycle in
epsilon Eri originally reported by Hatzes and coworkers, and we examine
the archival data from previous observations spanning 45 years. The data
show coexisting 3-year and 13-year periods leading into a broad activity
minimum that resembles a Maunder minimum-like state, followed by the
resurgence of a coherent 3-year cycle. The nearly continuous activity
record suggests the simultaneous operation of two stellar dynamos with
cycle periods of 2.95 ± 0.03 years and 12.7 ± 0.3 years, which, by
analogy with the solar case, suggests a revised identification of the
dynamo mechanisms that are responsible for the so-called "active" and
"inactive" sequences as proposed by Böhm-Vitense. Finally, based on
the observed properties of epsilon Eri, we argue that the rotational
history of the Sun is what makes it an outlier in the context of
magnetic cycles observed in other stars (as also suggested by its Li
depletion), and that a Jovian-mass companion cannot be the universal
explanation for the solar peculiarities.
Title: As Big and As Good As It Gets: The Large Monolithic Imager
for Lowell Observatory's 4.3-m Discovery Channel Telescope
Authors: Massey, Philip; Dunham, E. W.; Bida, T. A.; Collins, P.;
Hall, J. C.; Hunter, D. A.; Lauman, S.; Levine, S.; Neugent, K.; Nye,
R.; Oliver, R.; Schleicher, D.; Zoonematkermani, S.
Bibcode: 2013AAS...22134502M
Altcode:
The Large Monolithic Imager (LMI), a camera built at Lowell Observatory,
is currently undergoing commissioning on Lowell's new 4.3-m Discovery
Channel Telescope (DCT). At the heart of the LMI is the largest
charge-coupled device (CCD) that can be built using current fabrication
techniques, and the first of its kind to be made by e2v. The active area
of the chip is 92.2mmx92.4mm, and has 6144 by 6160 15-micron pixels. Our
choice of a single chip over a mosaic of smaller ones was inspired by
the success of USNO in deploying a similarly ginormous device made by
Semiconductor Technology Associates, Inc. There are some significant
advantages that a (very!) large single CCD has over a mosaic of smaller
ones. With a mosaic, one has to dither to fill in the gaps between the
chips for complete areal coverage. This is not only costly in overhead,
but it also poses a limitation in faint surface brightness studies,
as the sky brightness is constantly changing during the dithering
process. In addition, differences in the wavelength dependence of the
DQE can lead to differences in the color terms from chip to chip in
mosaics, requiring one to deal with each chip as a separate instrument
(see the Local Group Galaxy photometry of Massey et al. 2006, AJ, 131,
2478). The LMI avoids these problems. The Discovery Channel Telescope
is being built by Lowell Observatory in partnership with Discovery
Communications. First light took place in May 2012. Institutional DCT
partners include Boston University (in perpetuity), the University of
Maryland, and the University of Toledo. More about the DCT can be found
in the adjacent poster by Hall et al. The LMI has been made possible
thanks to a National Science Foundation grant (AST-1005313). We are
currently doing on-sky evaluation of the camera, as commissioning of
the DCT progresses, determining color terms, photometric zero-points,
astrometric characteristics, etc. We will present these results, along
with technical details and many pretty pictures (!), in our poster.
Title: Characterization of Potential U.S. Sites for the Cherenkov
Telescope Array
Authors: Ong, R. A.; Aune, T.; Hall, J.
Bibcode: 2013ICRC...33.2848O
Altcode: 2013arXiv1307.4719O
The Cherenkov Telescope Array (CTA) is a major ground-based observatory
proposed for gammaray astronomy. CTA is envisioned to consist of two
large arrays of atmospheric Cherenkov telescopes for the study of
sources of high-energy gamma rays in the energy range of a few tens
of GeV to beyond 100 TeV. One array would be located in the southern
hemisphere and one in the northern hemisphere. After a detailed search,
we have identified two potential sites in the USA for the northern
array. Both sites are located in northern Arizona. Here we describe
the two sites and the deployment of instrumentation to characterize
them. The characteristics of the sites, in terms of their atmospheric
and climatic properties, are described. We show recent data from the
automated monitoring equipment at the sites and compare these data
to a commercial simulation. Details regarding the facilities and
infrastructure required for the sites are also presented.
Title: A Search for Exozodis with Kepler
Authors: Stark, Christopher C.; Boss, A. P.; Weinberger, A. J.;
Jackson, B.; Endl, M.; Cochran, W. D.; Caldwell, C.; Agol, E.; Ford,
E. B.; Hall, J.; Ibrahim, K.; Li, J.
Bibcode: 2013AAS...22110406S
Altcode:
Planets embedded within exozodiacal dust disks may form large scale
clumpy dust structures by trapping dust into resonant orbits. When
viewed edge-on, these clumpy dust structures periodically pass in
front of their host star, creating orbit-long light curve variations
potentially detectable with Kepler. Here I present the first search
for these resonant structures in the inner regions of planetary
systems by analyzing the light curves of planet candidate host stars
identified by the Kepler mission. Our detection routine produced
one promising candidate disk structure associated with a hot Jupiter
planet candidate. However, radial velocity measurements show this planet
candidate to be an eclipsing binary with an unusual periodic signal. We
use our null result to place an upper limit on the frequency of high
contrast resonant dust clumps, a useful metric for future missions
that aim to image extrasolar planets in the inner regions of their
planetary systems.
Title: First Light from the 4.3-meter Discovery Channel Telescope
At Lowell Observatory
Authors: Hall, Jeffrey C.; Levine, S.
Bibcode: 2013AAS...22134501H
Altcode:
Seven years after groundbreaking on July 12, 2005, the 4.3-meter
Discovery Channel Telescope (DCT) is now complete and into
commissioning. We obtained first light images in mid 2012 with a 4K
x 4K CCD and have recently obtained our first images with the DCT's
main camera, the 6K x 6K Large Monolithic Imager (LMI, see adjacent
poster by Massey). We held a celebratory gala on July 21, 2012, in
Flagstaff. The DCT's delivered image quality is regularly subarcsecond
with near-uniform image quality across the FOV from zenith to >2
airmasses, although we have not fully commissioned the active optics
system. We attribute this to the outstanding quality of the mirror
figures, performed by the University of Arizona's College of Optical
Sciences (for M1) and L3 Brashear (for M2). The instrument cube at
the RC focus can accommodate four instruments plus the LMI. Designed
and built at Lowell Observatory, the cube also contains the DCT's
autoguider and wavefront sensor. First light instruments include
the 4000 DeVeny spectrograph (the former KPNO White Spectrograph), a
low-resolution, high-throughput IR spectrograph, and a higher-resolution
IR spectrograph/imager being built by Goddard Space Flight Center in
collaboration with the University of Maryland. We are seeking funding
for long-slit and fiber-fed echelle spectrographs for higher resolution
optical spectroscopy. The DCT can also be configured to host Nasmyth
and prime focus instruments. Discovery Communications and its founder
John Hendricks contributed $16M to the $53M cost of the telescope,
in return for naming rights and first rights to public, educational
use of images in their programming. Analysis of data and publication
by astronomers in professional journals follows the same procedure as
for any other major telescope facility. Discovery's first DCT feature,
"Scanning the Skies," aired on September 9, 2012. Future outreach plans
include initiating webcasts to classrooms via the Discovery Education
networks, reaching 30-40M schoolchildren across the USA. The DCT partner
consortium includes Boston University (in perpetuity), the University
of Maryland, and the University of Toledo, all of whom have ongoing,
long term access to the facility.
Title: Comet Observations [H17 Angel Peaks Observatory]
Authors: Hall, J.
Bibcode: 2012MPC..80338..13H
Altcode:
No abstract at ADS
Title: Comet C/2012 t5 (bressi)
Authors: Knoefel, A.; Buzzi, L.; Bressi, T. H.; Nishiyama, K.;
Sakamoto, T.; Masi, G.; Nocentini, F.; Masi, U.; Blythe, M.; Spitz,
G.; Brungard, R.; Paige, J.; Festler, P.; McVey, T.; Valdivia, A.;
Gall, C.; Dupouy, P.; de Vanssay, J. B.; Bryssinck, E.; Diepvens, A.;
Miller, P.; Roche, P.; Tripp, A.; Miles, R.; Holmes, R.; Foglia, S.;
Buz, L.; Vorobjov, T.; Johnson, J. A.; Boattini, A.; Christensen,
E. J.; Gibbs, A. R.; Grauer, A. D.; Hill, R. E.; Kowalski, R. A.;
Larson, S. M.; McNaught, R. H.; Ryan, W. H.; Sato, H.; Ligustri, R.;
Guido, E.; Sostero, G.; Howes, N.; Hall, J.; Devore, H.; Hug, G.;
Ruiz, P.; Koschny, D.; Busch, M.; Williams, G. V.
Bibcode: 2012MPEC....U...38K
Altcode:
No abstract at ADS
Title: Minor Planet Observations [H17 Angel Peaks Observatory]
Authors: Hall, J.
Bibcode: 2012MPC..80879...1H
Altcode:
No abstract at ADS
Title: First dark matter search results from a 4-kg CF3I
bubble chamber operated in a deep underground site
Authors: Behnke, E.; Behnke, J.; Brice, S. J.; Broemmelsiek, D.;
Collar, J. I.; Conner, A.; Cooper, P. S.; Crisler, M.; Dahl, C. E.;
Fustin, D.; Grace, E.; Hall, J.; Hu, M.; Levine, I.; Lippincott, W. H.;
Moan, T.; Nania, T.; Ramberg, E.; Robinson, A. E.; Sonnenschein, A.;
Szydagis, M.; Vázquez-Jáuregui, E.
Bibcode: 2012PhRvD..86e2001B
Altcode: 2012arXiv1204.3094B
New data are reported from the operation of a 4.0-kg CF3I
bubble chamber in the 6800-foot-deep SNOLAB underground laboratory. The
effectiveness of ultrasound analysis in discriminating alpha-decay
background events from single nuclear recoils has been confirmed,
with a lower bound of >99.3% rejection of alpha-decay events. Twenty
single nuclear recoil event candidates and three multiple bubble events
were observed during a total exposure of 553 kg-days distributed over
three different bubble nucleation thresholds. The effective exposure
for single bubble recoil-like events was 437.4 kg-days. A neutron
background internal to the apparatus, of known origin, is estimated to
account for five single nuclear recoil events and is consistent with
the observed rate of multiple bubble events. The remaining excess of
single bubble events exhibits characteristics indicating the presence
of an additional background. These data provide new direct detection
constraints on WIMP-proton spin-dependent scattering for WIMP masses
>20GeV/c2 and demonstrate significant sensitivity for
spin-independent interactions.
Title: Comment on ``First Results of the Phase II SIMPLE Dark
Matter Search''
Authors: Dahl, C. E.; Hall, J.; Lippincott, W. H.
Bibcode: 2012PhRvL.108y9001D
Altcode: 2011arXiv1111.6192D
Comment on M. Felizardo et al., Phys. Rev. Lett. 105, 211301
(2010).PRLTAO0031-9007 The authors of the Letter offer a
Reply.10.1103/PhysRevLett.105.211301
Title: Low-Mass WIMP Sensitivity and Statistical Discrimination of
Electron and Nuclear Recoils by Varying Luke-Neganov Phonon Gain in
Semiconductor Detectors
Authors: Pyle, M.; Bauer, D. A.; Cabrera, B.; Hall, J.; Schnee, R. W.;
Basu Thakur, R.; Yellin, S.
Bibcode: 2012JLTP..167.1081P
Altcode: 2012arXiv1201.3685P; 2012JLTP..tmp...81P; 2012JLTP..tmp..272P
Amplifying the phonon signal in a semiconductor dark matter detector
can be accomplished by operating at high voltage bias and converting
the electrostatic potential energy into Luke-Neganov phonons. This
amplification method has been validated at up to | E|=40 V/cm without
producing leakage in CDMS II Ge detectors, allowing sensitivity to
a benchmark WIMP with mass M χ =8 GeV/c2 and
σ=1.8×10-42 cm2 (with significant sensitivity
for M χ >2 GeV/c2) assuming flat electronic
recoil backgrounds near threshold. Furthermore, for the first
time we show that differences in Luke-Neganov gain for nuclear and
electronic recoils can be used to discriminate statistically between
low-energy background and a hypothetical WIMP signal by operating
at two distinct voltage biases. Specifically, 99% of events have
p-value <10-8 for a simulated 20 kg-day experiment with
a benchmark WIMP signal with M χ =8 GeV/c2
and σ=3.3×10-41 cm2.
Title: Mars Balloon Science
Authors: Wolf, A.; Beegle, L.; Raymond, C.; Plaut, J.; Pollard, B.;
Gim, Y.; Wu, X.; Hall, J.
Bibcode: 2012LPICo1679.4294W
Altcode:
Balloons are uniquely suitable platforms for some observations important
for Mars science and future human exploration. They are technologically
within reach, and are small enough to be packaged as secondary payloads.
Title: Minor Planet Observations [H17 Angel Peaks Observatory]
Authors: Hall, J.
Bibcode: 2012MPC..79335...1H
Altcode:
No abstract at ADS
Title: Solar Twins and Stellar Maunder Minima
Authors: Hall, Jeffrey C.
Bibcode: 2012AAS...22050001H
Altcode:
In 1966, Olin C. Wilson undertook an answer to the question “Does
the chromospheric activity of main-sequence stars vary with time, and
if so, how?”, initiating the so-called HK Project at Mount Wilson
Observatory, which resulted in a magnificent 43-year data set and
which has spawned a number of complementary synoptic programs in both
hemispheres. Subsequent developments, in particular the realization
that activity controls angular momentum evolution in the stars and
Sun, that solar activity modulates irradiance, and that there was a
pronounced response of terrestrial climate to the Maunder Minimum,
spurred efforts to identify solar twins, stars that Giusa Cayrel de
Strobel required to possess “fundamental physical parameters very
similar, if not identical to those of the Sun.” Non-cycling states
appear to occur in the Mount Wilson stars and in other synoptic data
with about the same frequency that the Sun’s grand minima occur in the
long-term proxy record, suggesting that stellar analogs of the Maunder
Minimum may be used to guide understanding of the Sun’s state in the
late seventeenth century and, as appears possible given the extended
Cycle 23/24 minimum, in the near future. However, the magnitude limits
of the existing surveys have kept the sample of solar twins small and
long-term monitoring programs have only recently begun to accumulate
good time-domain data beyond the canonical HK-index. Addressing these
and other issues toward understanding prolonged stellar minima is
therefore a key area of inquiry in solar-stellar connection work for
the next decade. I will summarize the state of the field and the most
promising lines of work for the immediate future. I and my colleagues
Wes Lockwood and Brian Skiff sincerely appreciate the National Science
Foundation’s long-time support of stellar cycles work at Lowell
Observatory.
Title: Search for annual modulation in low-energy CDMS-II data
Authors: CDMS Collaboration; Ahmed, Z.; Akerib, D. S.; Anderson, A. J.;
Arrenberg, S.; Bailey, C. N.; Balakishiyeva, D.; Baudis, L.; Bauer,
D. A.; Brink, P. L.; Bruch, T.; Bunker, R.; Cabrera, B.; Caldwell,
D. O.; Cooley, J.; Cushman, P.; Daal, M.; DeJongh, F.; Di Stefano,
P. C. F.; Dragowsky, M. R.; Fallows, S.; Figueroa-Feliciano, E.;
Filippini, J.; Fox, J.; Fritts, M.; Golwala, S. R.; Hall, J.; Hertel,
S. A.; Hofer, T.; Holmgren, D.; Hsu, L.; Huber, M. E.; Kamaev, O.;
Kiveni, M.; Kos, M.; Leman, S. W.; Liu, S.; Mahapatra, R.; Mandic,
V.; McCarthy, K. A.; Mirabolfathi, N.; Moore, D. C.; Nelson, H.;
Ogburn, R. W.; Phipps, A.; Prasad, K.; Pyle, M.; Qiu, X.; Rau, W.;
Reisetter, A.; Ricci, Y.; Saab, T.; Sadoulet, B.; Sander, J.; Schnee,
R. W.; Seitz, D.; Serfass, B.; Speller, D.; Sundqvist, K. M.; Tarka,
M.; Thakur, R. B.; Villano, A. N.; Welliver, B.; Yellin, S.; Yoo,
J.; Young, B. A.; Zhang, J.
Bibcode: 2012arXiv1203.1309C
Altcode:
We report limits on annual modulation of the low-energy event rate
from the Cryogenic Dark Matter Search (CDMS II) experiment at the
Soudan Underground Laboratory. Such a modulation could be produced
by interactions from Weakly Interacting Massive Particles (WIMPs)
with masses ~10 GeV/c^2. We find no evidence for annual modulation in
the event rate of veto-anticoincident single-detector interactions
consistent with nuclear recoils, and constrain the magnitude of any
modulation to <0.06 event [keVnr kg day]^-1 in the 5-11.9 keVnr
energy range at the 99% confidence level. These results disfavor an
explanation for the reported modulation in the 1.2-3.2 keVee energy
range in CoGeNT in terms of nuclear recoils resulting from elastic
scattering of WIMPs at >98% confidence. For events consistent with
electron recoils, no significant modulation is observed for either
single- or multiple-detector interactions in the 3.0-7.4 keVee range.
Title: Minor Planet Observations [H17 Angel Peaks Observatory]
Authors: Hall, J.
Bibcode: 2012MPC..77794...1H
Altcode:
No abstract at ADS
Title: Lowell Observatory's Discovery Channel Telescope: Status,
Key Science, and Opportunities
Authors: Hall, Jeffrey C.; Levine, S. E.
Bibcode: 2012AAS...21942224H
Altcode:
On July 12, 2005 Lowell Observatory broke ground at the construction
site of the 4.3-meter Discovery Channel Telescope (DCT) near Happy
Jack, AZ, 40 miles southeast of Flagstaff and at an elevation of
7,800'. The facility is now nearly complete, with testing of the
primary mirror and active optics well underway and testing at RC focus
imminent. First light is expected by May 2012. Lowell and its
partners, Boston University and the University of Maryland, will use
the DCT for a variety of projects including studies of star formation
in dwarf galaxies, cometary nuclei and KBOs, activity variations of
Sun-like stars, and ToO follow-up observations of GRBs. Discovery
Communications will use results of projects carried out by Lowell
and its partners in broadcast and online media, reaching 99 million
households in the USA and over 1.5 billion subscribers worldwide. The
first major feature on the making of the telescope is expected to air
on Discovery in June 2012. In this poster we describe the general
capabilities of the telescope, first light instrument suite, and key
science projects. We also seek an additional partner to join us, BU,
and UMD and invite interested parties or institutions to visit this
poster and the adjacent one, presented by DCT Commissioning Scientist
Stephen Levine, for more information.
Title: The Lowell Observatory Predoctoral Scholar Program
Authors: Hall, Jeffrey C.; Prato, L. A.
Bibcode: 2012AAS...21923604H
Altcode:
Lowell Observatory is pleased to solicit applications for our
Predoctoral Scholar Fellowship Program. Now beginning its fifth year,
this program provides unique research opportunities to graduate
students in good standing and currently enrolled at Ph.D. granting
institutions. Lowell staff research spans a wide range of topics
from astronomical instrumentation to icy bodies in our solar system,
exoplanet science, and stellar populations and dwarf irregular
galaxies. The Observatory's new 4.3-meter Discovery Channel
Telescope is on track for first light by mid-2012, making this a
particularly exciting time in our history. Student research is expected
to lead to a thesis dissertation appropriate for graduation at the
doctoral level at the student's home institution. Currently,
three students are enrolled and three have successfully completed
their thesis work at Lowell and moved on to postdocs and astronomy
jobs elsewhere. The Observatory provides competitive compensation
and full benefits to student scholars. For more information, see
http://www2.lowell.edu/rsch/predoc.php and links therein. Applications
for Fall 2012 are due by May 1, 2012.
Title: Lowell Observatory's Discovery Channel Telescope: Telescope
and Systems Specifications and Commissioning Status
Authors: Levine, Stephen; Hall, J. C.
Bibcode: 2012AAS...21942225L
Altcode:
Lowell Observatory's 4.3-meter Discovery Channel Telescope is in the
process of being commissioned now. The telescope is located 40 miles
southeast of Flagstaff,AZ at an elevation of 7,800 feet. On sky testing
of the major subsystems began in early fall 2011, with commissioning
work leading up to first light in late spring of 2012. We present a
review of the design specifications of the telescope and its major
subsystems. This is followed by a discussion of the commissioning
time-line, and current status and performance of the telescope, and
optics (including the active optics support system for the primary
mirror).
Title: Results of the First Observations with the Hamburg Robotic
Telescope
Authors: Mittag, M.; Hempelmann, A.; González-Pérez, J. N.; Schmitt,
J. H. M. M.; Hall, J. C.
Bibcode: 2011ASPC..448.1187M
Altcode: 2011csss...16.1187M
The results of the first scientific observations with the Hamburg
Robotic Telescope (HRT) are presented. These observations were performed
between October 2008 and August 2009. The goals of this program
were a test of the observational performance of the telescope and the
creation of a transformation equation from the HRT S-index to the Mount
Wilson S-index. The mean of the deviations between the transformed HRT
S-Indices and the corresponding Mount Wilson S-Indices is ≍4%. These
deviations can be -- at least partially -- explained by stellar
variability and the non-simultaneity of the observations. Furthermore,
the first monitoring of several stars was performed.
Title: Minor Planet Observations [H17 Angel Peaks Observatory]
Authors: Hall, J.
Bibcode: 2011MPC..77396...1H
Altcode:
No abstract at ADS
Title: Minor Planet Observations [H17 Angel Peaks Observatory]
Authors: Hall, J.
Bibcode: 2011MPC..77005...1H
Altcode:
No abstract at ADS
Title: A near-infrared spectrograph for the Discovery Channel
Telescope
Authors: Roe, H. G.; Dunham, E. W.; Bida, T. A.; Hall, J. C.;
Degroff, W.
Bibcode: 2011epsc.conf.1823R
Altcode: 2011DPS....43.1823R
Lowell Observatory is constructing the Discovery Channel Telescope
(DCT) at Happy Jack, Arizona, approximately an hour from Lowell's main
campus in Flagstaff, Arizona. The DCT is a 4.3-m optical/ infrared
telescope. Construction of the telescope is complete and First Light of
the DCT is planned for 2012Q2. In its initial configuration instruments
will be co-mounted on a rotatable/selectable cube at the Cassegrain
focus. Motorized deployable fold mirrors enable rapid switching amongst
instruments. In the future the Nasmyth foci will be available for larger
instruments as well. The first generation of instruments on DCT include:
the Large Monolithic Imager (LMI), the Near-Infrared High-Throughput
Spectrograph (NIHTS, pronounced "nights"), and the DeVeny optical
spectrograph. The LMI contains a single large 6.1x6.1 K detector with
a 12.5 arcmin2 FOV. NIHTS is a low resolution efficient near-infrared
spectrograph and is the subject of this presentation. The DeVeny
is Lowell's existing optical spectrograph with resolutions available
between 500 and 4000. NIHTS is a low-resolution high-throughput infrared
spectrograph covering 0.9-2.4 μm in a single fixed spectral setting at
a resolution of »100. For simplicity and replicability NIHTS contains
no moving parts. The science detector is a 10242 HAWAII-1 array. The
fixed slit plate features an 80" long slit with several different slit
widths (2,3,4 and 12 pixels) available along its length. The widest
slit width is designed to allow accurate flux calibration, while the
3 and 4-pixel slits are closely matched to typical seeing at the DCT
site (0.86" mean). Different resolutions will be rapidly selectable
by dithering the telescope, and a typical observation is anticipated
to involve a sequence of dithers both at the desired resolution and at
SED resolution for calibration purposes. Offset guiding and wavefront
sensing to control the active optics of the primary mirror are provided
by the facility via deployable probes in the instrument cube. Target
acquisition and slit-guiding is possible in the optical with the LMI
or in the near-infrared with an In- GaAs slit-viewing camera that
is part of NIHTS. Because the fold mirror to NIHTS is a dichroic,
simultaneous optical imaging with LMI and near-infrared spectroscopy
with NIHTS is enabled. NASA funded the construction of NIHTS as part
of a larger project, the Kuiper Spectral Survey (KSS), and will be
available to all users of the DCT.
Title: Recent Advancements in Titan Balloon Techniques
Authors: Reh, K.; Hall, J.; Vargas, A.; Colonius, T.; Dieudonne, W.;
Coustenis, A.; Lunine, J.; Deramecourt, A.
Bibcode: 2011epsc.conf..519R
Altcode: 2011DPS....43..519R
Suggestions for the use of balloons to explore Saturn's icy moon
Titan have been proposed for more than 40 years. Many alternative
mission concepts [1], [2], [4], [5] have been developed since that
time, catalyzed by scientific discoveries resulting from the Voyager
1 flyby in 1980 and the Cassini- Huygens mission that arrived in
2004. The results from Cassini-Huygens, in particular, revealed Titan
to be a complex and fascinating world with diverse topographical
features and a methane-based hydrological cycle. The Huygens probe
[3] demonstrated excellent visibility below a 10 km altitude with its
high resolution images and measured low wind speeds at the surface
(< 1-2 m/s). The motivation to return to Titan has intensified
in the wake of these results and the increasing priority of related
scientific questions. Because of the uniquely dense, high molecular
weight atmosphere, very small diurnal temperature variations and low
gravity, it is widely recognized that a buoyant vehicle could provide
an unparalleled means of in situ exploration on a global scale. This
poster provides a summary of recent advancements in Titan balloon
techniques that someday will enable a return to Titan on a grand scale.
Title: Comet Observations [H17 Angel Peaks Observatory]
Authors: Hall, J.
Bibcode: 2011MPC..76274..22H
Altcode:
No abstract at ADS
Title: Recent Advancements in Titan Balloon Techniques
Authors: Reh, K.; Hall, J.; Vargas, A.; Colonius, T.; Dieudonne, W.;
Coustenis, A.; Lunine, J.; Deramecourt, A.
Bibcode: 2011epsc.conf..522R
Altcode: 2011DPS....43..522R
Suggestions for the use of balloons to explore Saturn's icy moon
Titan have been proposed for more than 40 years. Many alternative
mission concepts [1], [2], [4], [5] have been developed since that
time, catalyzed by scientific discoveries resulting from the Voyager
1 flyby in 1980 and the Cassini- Huygens mission that arrived in
2004. The results from Cassini-Huygens, in particular, revealed Titan
to be a complex and fascinating world with diverse topographical
features and a methane-based hydrological cycle. The Huygens probe
[3] demonstrated excellent visibility below a 10 km altitude with its
high resolution images and measured low wind speeds at the surface
(< 1-2 m/s). The motivation to return to Titan has intensified
in the wake of these results and the increasing priority of related
scientific questions. Because of the uniquely dense, high molecular
weight atmosphere, very small diurnal temperature variations and low
gravity, it is widely recognized that a buoyant vehicle could provide an
unparalleled means of in situ exploration on a global scale. This oral
presentation provides a summary of recent advancements in Titan balloon
techniques that someday will enable a return to Titan on a grand scale.
Title: Minor Planet Observations [H17 Angel Peaks Observatory]
Authors: Hall, J.
Bibcode: 2011MPC..76561...1H
Altcode:
No abstract at ADS
Title: Comet C/2011 s2 (kowalski)
Authors: Skvarc, J.; Knoefel, A.; Haver, R.; Gorelli, R.; Buzzi, L.;
Sarneczky, K.; Jung, M.; Bill, H.; Pettarin, E.; Kowalski, R. A.;
Ahern, J. D.; Beshore, E. C.; Boattini, A.; Garradd, G. J.; Gibbs,
A. R.; Tricarico, P.; Grauer, A. D.; Hill, R. E.; Larson, S. M.;
McNaught, R. H.; Blythe, M.; Spitz, G.; Brungard, R.; Paige, J.;
Festler, P.; McVey, T.; Valdivia, A.; Gall, C.; Emmerich, M.; Melchert,
S.; Jaeger, M.; Prosperi, E.; Vollmann, W.; Klein, M.; Ryan, W. H.;
Ryan, E. V.; Guido, E.; Sostero, G.; Howes, N.; Sato, H.; Baroni, S.;
Concari, P.; Foglia, S.; Galli, G.; Tombelli, M.; Hall, J.; Holmes,
R.; Vorobjov, T.; Hug, G.; Birtwhistle, P.; Williams, G. V.
Bibcode: 2011MPEC....T...12S
Altcode:
No abstract at ADS
Title: Combined limits on WIMPs from the CDMS and EDELWEISS
experiments
Authors: Ahmed, Z.; Akerib, D. S.; Armengaud, E.; Arrenberg, S.;
Augier, C.; Bailey, C. N.; Balakishiyeva, D.; Baudis, L.; Bauer, D. A.;
Benoît, A.; Bergé, L.; Blümer, J.; Brink, P. L.; Broniatowski,
A.; Bruch, T.; Brudanin, V.; Bunker, R.; Cabrera, B.; Caldwell,
D. O.; Censier, B.; Chapellier, M.; Chardin, G.; Charlieux, F.;
Cooley, J.; Coulter, P.; Cox, G. A.; Cushman, P.; Daal, M.; Defay,
X.; de Jesus, M.; Dejongh, F.; di Stefano, P. C. F.; Dolgorouki, Y.;
Domange, J.; Dumoulin, L.; Dragowsky, M. R.; Eitel, K.; Fallows, S.;
Figueroa-Feliciano, E.; Filippini, J.; Filosofov, D.; Fourches, N.;
Fox, J.; Fritts, M.; Gascon, J.; Gerbier, G.; Gironnet, J.; Golwala,
S. R.; Gros, M.; Hall, J.; Hennings-Yeomans, R.; Henry, S.; Hertel,
S. A.; Hervé, S.; Holmgren, D.; Hsu, L.; Huber, M. E.; Juillard, A.;
Kamaev, O.; Kiveni, M.; Kluck, H.; Kos, M.; Kozlov, V.; Kraus, H.;
Kudryavtsev, V. A.; Leman, S. W.; Liu, S.; Loaiza, P.; Mahapatra, R.;
Mandic, V.; Marnieros, S.; Martinez, C.; McCarthy, K. A.; Mirabolfathi,
N.; Moore, D.; Nadeau, P.; Navick, X. -F.; Nelson, H.; Nones, C.;
Ogburn, R. W.; Olivieri, E.; Pari, P.; Pattavina, L.; Paul, B.; Phipps,
A.; Pyle, M.; Qiu, X.; Rau, W.; Reisetter, A.; Ricci, Y.; Robinson,
M.; Rozov, S.; Saab, T.; Sadoulet, B.; Sander, J.; Sanglard, V.;
Schmidt, B.; Schnee, R. W.; Scorza, S.; Seitz, D. N.; Semikh, S.;
Serfass, B.; Sundqvist, K. M.; Tarka, M.; Torrento-Coello, A. S.;
Vagneron, L.; Verdier, M. -A.; Walker, R. J.; Wikus, P.; Yakushev,
E.; Yellin, S.; Yoo, J.; Young, B. A.; Zhang, J.
Bibcode: 2011PhRvD..84a1102A
Altcode: 2011arXiv1105.3377C
The CDMS and EDELWEISS collaborations have combined the results of
their direct searches for dark matter using cryogenic germanium
detectors. The total data set represents 614kg·days equivalent
exposure. A straightforward method of combination was chosen for
its simplicity before data were exchanged between experiments. The
results are interpreted in terms of limits on spin-independent weakly
interacting, massive particle (WIMP)-nucleon cross section. For a WIMP
mass of 90GeV/c2, where this analysis is most sensitive,
a cross section of 3.3×10-44cm2 is excluded at
90% C.L. At higher WIMP masses, the combination improves the individual
limits, by a factor 1.6 above 700GeV/c2. Alternative methods
of combining the data provide stronger constraints for some ranges of
WIMP masses and weaker constraints for others.
Title: Observations and Orbits of Comets
Authors: Tesi, L.; Bacci, P.; Fagioli, G.; Bacci, R.; Casali, M.;
Coffano, A.; Marinello, W.; Micheli, M.; Pizzetti, G.; Cernis, K.;
Zdanavicius, J.; Maskoliunas, M.; Haver, R.; Foglia, S.; Galli, G.;
Buzzi, L.; Naves, R.; Campas, M.; Hasubick, W.; Donati, S.; McAndrew,
S. G.; Sanchez C., A.; Donato, L.; Gonano, V.; Travagini, M.; Bill, H.;
Baransky, A.; Buriev, A.; Ponomarenko, V.; Scotti, J. V.; Kowalski,
R. A.; Ahern, J. D.; Beshore, E. C.; Boattini, A.; Garradd, G. J.;
Gibbs, A. R.; Tricarico, P.; Grauer, A. D.; Hill, R. E.; Larson,
S. M.; McNaught, R. H.; Blythe, M.; Spitz, G.; Brungard, R.; Paige,
J.; Festler, P.; McVey, T.; Valdivia, A.; Brewington, H.; Dembicky,
J.; Harvanek, M.; Ketzeback, B.; Long, D.; Pan, K.; Malanushenko, O.;
McMillan, R.; Snedden, S.; Watters, S.; Sarneczky, K.; Durig, D. T.;
Uriostegui, J. R.; Danusantoso, J. F.; Kharel, S.; Duenas, D. E.;
Rice, A. C.; Vasquez, J. A.; Murphree, C. L.; Koury, E. S.; Castellano,
J.; Ferrando, R.; Vidal, J. R.; Baldris, F.; Kocher, P.; Jaeger, M.;
Prosperi, E.; Vollmann, W.; Rinner, C.; Kugel, F.; Nicolas, J.; Bel,
J.; Borghini, W.; Bryssinck, E.; Sachot, G.; Soulier, J. F.; Diepvens,
A.; Dangl, G.; Hills, K.; Takahashi, T.; Novichonok, A.; Baroni, S.;
Concari, P.; Tombelli, M.; Chestnov, D.; Sato, H.; Herald, D.; Lister,
T.; Guido, E.; Howes, N.; Sostero, G.; McCormick, J.; Primak, N.;
Schultz, A.; Thiel, J.; Goggia, T.; Glinos, T.; Plaksa, S.; Elenin,
L.; Hall-Angel Peaks Observatory, J.; Hall, J.; Holmes, R.; Vorobjov,
T.; Linder, T.; Mills, M.; Hug, G.; Sherrod, P. C.; Bell, C.; Jehin,
E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P.; Limon,
F.; Gonzalez, J.; Pena Ciriza, F.; Del Maes, A.; Hernandez, J. F.;
Garcia, F.; Fletcher, J.; Climent, T.; Williams, G. V.
Bibcode: 2011MPEC....N...13T
Altcode:
No abstract at ADS
Title: Comet Observations [H17 Angel Peaks Observatory]
Authors: Hall, J.
Bibcode: 2011MPC..75359..10H
Altcode:
No abstract at ADS
Title: Minor Planet Observations [H17 Angel Peaks Observatory]
Authors: Hall, J.
Bibcode: 2011MPC..75509...1H
Altcode:
No abstract at ADS
Title: 2011 ME
Authors: Blythe, M.; Spitz, G.; Brungard, R.; Paige, J.; Festler, P.;
McVey, T.; Valdivia, A.; McGaha, J. E.; Hall-Angel Peaks Observatory,
J.; Hall, J.; Hug, G.; Birtwhistle, P.; Tomatic, A. U.
Bibcode: 2011MPEC....M...24B
Altcode:
No abstract at ADS
Title: Minor Planet Observations [H17 Angel Peaks Observatory]
Authors: Hall, J.
Bibcode: 2011MPC..75287...1H
Altcode:
No abstract at ADS
Title: Search for inelastic dark matter with the CDMS II experiment
Authors: Ahmed, Z.; Akerib, D. S.; Arrenberg, S.; Bailey, C. N.;
Balakishiyeva, D.; Baudis, L.; Bauer, D. A.; Brink, P. L.; Bruch, T.;
Bunker, R.; Cabrera, B.; Caldwell, D. O.; Cooley, J.; Do Couto E Silva,
E.; Cushman, P.; Daal, M.; Dejongh, F.; di Stefano, P.; Dragowsky,
M. R.; Duong, L.; Fallows, S.; Figueroa-Feliciano, E.; Filippini,
J.; Fox, J.; Fritts, M.; Golwala, S. R.; Hall, J.; Hennings-Yeomans,
R.; Hertel, S. A.; Holmgren, D.; Hsu, L.; Huber, M. E.; Kamaev, O.;
Kiveni, M.; Kos, M.; Leman, S. W.; Liu, S.; Mahapatra, R.; Mandic,
V.; McCarthy, K. A.; Mirabolfathi, N.; Moore, D.; Nelson, H.; Ogburn,
R. W.; Phipps, A.; Pyle, M.; Qiu, X.; Ramberg, E.; Rau, W.; Razeti,
M.; Reisetter, A.; Resch, R.; Saab, T.; Sadoulet, B.; Sander, J.;
Schnee, R. W.; Seitz, D. N.; Serfass, B.; Sundqvist, K. M.; Tarka,
M.; Wikus, P.; Yellin, S.; Yoo, J.; Young, B. A.; Zhang, J.
Bibcode: 2011PhRvD..83k2002A
Altcode: 2010arXiv1012.5078C
Results are presented from a reanalysis of the entire five-tower
data set acquired with the Cryogenic Dark Matter Search (CDMS II)
experiment at the Soudan Underground Laboratory, with an exposure of 969
kg-days. The analysis window was extended to a recoil energy of 150 keV,
and an improved surface-event background-rejection cut was defined to
increase the sensitivity of the experiment to the inelastic dark matter
(iDM) model. Three dark matter candidates were found between 25 keV and
150 keV. The probability to observe three or more background events in
this energy range is 11%. Because of the occurrence of these events,
the constraints on the iDM parameter space are slightly less stringent
than those from our previous analysis, which used an energy window of
10-100 keV.
Title: Observations and Orbits of Comets
Authors: Tesi, L.; Bacci, P.; Fagioli, G.; Gajdos, S.; Buzzi, L.;
Naves, R.; Campas, M.; Kadota, K.; Klein, M.; Jung, M.; Feger, F.;
Bill, H.; Blythe, M.; Spitz, G.; Brungard, R.; Paige, J.; Festler,
P.; McVey, T.; Valdivia, A.; Brewington, H.; Dembicky, J.; Harvanek,
M.; Ketzeback, B.; Long, D.; Pan, K.; Malanushenko, O.; McMillan, R.;
Snedden, S.; Watters, S.; Sarneczky, K.; Durig, D. T.; Uriostegui,
J. R.; Tran, J. T.; Nichols, E. M.; Strickland, T. D.; Torres Perez,
J. A.; Murp, C. L.; Essix, G. V.; Williams, K. A.; Morris, T. A.; Rice,
A. C.; Va, J. A.; Duenas, D. E.; Kharel, S.; Grishaw, A. C.; Emerson,
S. E.; Guhlin, A. R.; Edman, J. R.; Johnson, E. C.; Danusantoso,
J. F.; Castellano, J.; Vidal, J. R.; Baldris, F.; Salto, J. L.;
Salto, A.; Jaeger, M.; Prosperi, E.; Vollmann, W.; Rinner, C.; Kugel,
F.; Nicolas, J.; Noel, T.; Hills, K.; Takahashi, T.; Bryssinck, E.;
Plaksa, S.; McNaught, R. H.; Ahern, J. D.; Beshore, E. C.; Boattini,
A.; Garradd, G. J.; Gibbs, A. R.; Grauer, A. D.; Hill, R. E.; Kowalski,
R. A.; Larson, S. M.; Lister, T.; Fulton, B. J.; Dymock, R.; Sato,
H.; Ligustri, R.; Chestnov, D.; Novichonok, A.; Elenin, L.; Hall, J.;
Sherrod, P. C.; Bell, C.; Limon, F.; Gonzalez, J.; Busch, M.; Drefke,
A.; Geffert, P.; Koschny, D.; Kracht, R.; Kresken, R.; Hernandez,
J. F.; Garcia, F.; Climent, T.
Bibcode: 2011MPEC....M...31T
Altcode:
No abstract at ADS
Title: Minor Planet Observations [H17 Angel Peaks Observatory]
Authors: Hall, J.
Bibcode: 2011MPC..75003...1H
Altcode:
No abstract at ADS
Title: Results from a Low-Energy Analysis of the CDMS II Germanium
Data
Authors: Ahmed, Z.; Akerib, D. S.; Arrenberg, S.; Bailey, C. N.;
Balakishiyeva, D.; Baudis, L.; Bauer, D. A.; Brink, P. L.; Bruch, T.;
Bunker, R.; Cabrera, B.; Caldwell, D. O.; Cooley, J.; Do Couto E Silva,
E.; Cushman, P.; Daal, M.; Dejongh, F.; di Stefano, P.; Dragowsky,
M. R.; Duong, L.; Fallows, S.; Figueroa-Feliciano, E.; Filippini,
J.; Fox, J.; Fritts, M.; Golwala, S. R.; Hall, J.; Hennings-Yeomans,
R.; Hertel, S. A.; Holmgren, D.; Hsu, L.; Huber, M. E.; Kamaev, O.;
Kiveni, M.; Kos, M.; Leman, S. W.; Liu, S.; Mahapatra, R.; Mandic,
V.; McCarthy, K. A.; Mirabolfathi, N.; Moore, D.; Nelson, H.; Ogburn,
R. W.; Phipps, A.; Pyle, M.; Qiu, X.; Ramberg, E.; Rau, W.; Reisetter,
A.; Resch, R.; Saab, T.; Sadoulet, B.; Sander, J.; Schnee, R. W.;
Seitz, D. N.; Serfass, B.; Sundqvist, K. M.; Tarka, M.; Wikus, P.;
Yellin, S.; Yoo, J.; Young, B. A.; Zhang, J.
Bibcode: 2011PhRvL.106m1302A
Altcode: 2010arXiv1011.2482C
We report results from a reanalysis of data from the Cryogenic
Dark Matter Search (CDMS II) experiment at the Soudan Underground
Laboratory. Data taken between October 2006 and September 2008
using eight germanium detectors are reanalyzed with a lowered, 2 keV
recoil-energy threshold, to give increased sensitivity to interactions
from weakly interacting massive particles (WIMPs) with masses below
∼10GeV/c2. This analysis provides stronger constraints
than previous CDMS II results for WIMP masses below 9GeV/c2
and excludes parameter space associated with possible low-mass WIMP
signals from the DAMA/LIBRA and CoGeNT experiments.
Title: Minor Planet Observations [H17 Angel Peaks Observatory]
Authors: Hall, J.
Bibcode: 2011MPC..74630...1H
Altcode:
No abstract at ADS
Title: Minor Planet Observations [H17 Angel Peaks Observatory]
Authors: Hall, J.
Bibcode: 2011MPC..74230...1H
Altcode:
No abstract at ADS
Title: Minor Planet Observations [H17 Angel Peaks Observatory]
Authors: Hall, J.
Bibcode: 2011MPC..73908...1H
Altcode:
No abstract at ADS
Title: Improved Limits on Spin-Dependent WIMP-Proton Interactions
from a Two Liter CF3I Bubble Chamber
Authors: Behnke, E.; Behnke, J.; Brice, S. J.; Broemmelsiek, D.;
Collar, J. I.; Cooper, P. S.; Crisler, M.; Dahl, C. E.; Fustin, D.;
Hall, J.; Hinnefeld, J. H.; Hu, M.; Levine, I.; Ramberg, E.; Shepherd,
T.; Sonnenschein, A.; Szydagis, M.
Bibcode: 2011PhRvL.106b1303B
Altcode: 2010arXiv1008.3518B
Data from the operation of a bubble chamber filled with 3.5 kg of
CF3I in a shallow underground site are reported. An
analysis of ultrasound signals accompanying bubble nucleations
confirms that alpha decays generate a significantly louder acoustic
emission than single nuclear recoils, leading to an efficient
background discrimination. Three dark matter candidate events were
observed during an effective exposure of 28.1kgday, consistent with a
neutron background. This observation provides strong direct detection
constraints on weakly interacting massive particle (WIMP)-proton
spin-dependent scattering for WIMP masses >20GeV/c2.
Title: Minor Planet Observations [H17 Angel Peaks Observatory]
Authors: Hall, J.
Bibcode: 2011MPC..73453...2H
Altcode:
No abstract at ADS
Title: Lessons from Solar Twins
Authors: Hall, Jeffrey
Bibcode: 2010S&T...120a..22H
Altcode:
No abstract at ADS
Title: The Discovery Channel Telescope: early integration
Authors: Smith, Byron; Chylek, Tomas; Degroff, Bill; Finley, David;
Hall, Jeffrey; Lotz, Paul J.; McCreight, Brad; Venetiou, Alexander
Bibcode: 2010SPIE.7733E..0AS
Altcode: 2010SPIE.7733E...8S
The Discovery Channel Telescope (DCT) is a 4.3-meter astronomical
research telescope being built in northern Arizona as a partnership
between Discovery Communications and Lowell Observatory. The telescope
will be able to support substantial instrument payloads at Cassegrain,
Nasmyth, and prime foci, and high observing cadences. The first-light
configuration will be as an f/6.1 Ritchey-Chrétien at Cassegrain with
a 30 arc-minute field-of-view. Major facility work is complete, and
the telescope is currently in the integration phase with first-light
anticipated in 2011. We present an overview of the design and progress
to date, and include plans for final integration, commissioning,
and early science.
Title: Computational Modeling and Experiments of Natural Convection
for a Titan Montgolfiere
Authors: Samanta, Arnab; Appelö, Daniel; Colonius, Tim; Nott, Julian;
Hall, Jeffrey
Bibcode: 2010AIAAJ..48.1007S
Altcode:
No abstract at ADS
Title: Structure and rifting evolution of the northern Newfoundland
Basin from Erable multichannel seismic reflection profiles across
the southeastern margin of Flemish Cap
Authors: Welford, J. K.; Smith, J. A.; Hall, J.; Deemer, S.;
Srivastava, S. P.; Sibuet, J. -C.
Bibcode: 2010GeoJI.180..976W
Altcode:
We present the results from processing and interpreting five lines
from the 1992 Erable multichannel seismic reflection experiment
extending from the southeastern margin of Flemish Cap into the northern
Newfoundland Basin. These profiles reveal significant along strike
variations in the rifting styles experienced by Flemish Cap. In the
southwest, a 100-km-wide transition zone is identified between thinned
continental crust and thin oceanic crust. Similar to the conjugate
Galicia Bank and Iberian margins, this transition zone contains a
section of deep basement adjacent to a series of shallower ridges and
is interpreted as exhumed serpentinized mantle. Along strike towards
the northeast, this transition zone pinches out completely within
100 km and is replaced by thin oceanic crust directly adjacent to
thinned continental crust. By interpreting nearby seismic profiles
and profiles on the conjugate margins using the same classification
criteria, we construct regional maps of the distribution of crustal
domains on both sides of the North Atlantic. These maps reveal
significant variations in rifting style on the conjugate margins and
along strike of each margin and also highlight the role of ancient
transfer zones in compartmentalizing these rifting variations into
four distinct regions. We propose that the limited localization of
shallow topographically high serpentinized peridotite ridges on the
Newfoundland-Iberia and Flemish Cap-Galicia Bank conjugate margins,
was directly related to an increase in the rate of extension following
the separation of Flemish Cap and Galicia Bank which exhumed deeper,
less serpentinized mantle.
Title: Dark Matter Search Results from the CDMS II Experiment
Authors: CDMS II Collaboration; Ahmed, Z.; Akerib, D. S.; Arrenberg,
S.; Bailey, C. N.; Balakishiyeva, D.; Baudis, L.; Bauer, D. A.; Brink,
P. L.; Bruch, T.; Bunker, R.; Cabrera, B.; Caldwell, D. O.; Cooley,
J.; Cushman, P.; Daal, M.; DeJongh, F.; Dragowsky, M. R.; Duong,
L.; Fallows, S.; Figueroa-Feliciano, E.; Filippini, J.; Fritts, M.;
Golwala, S. R.; Grant, D. R.; Hall, J.; Hennings-Yeomans, R.; Hertel,
S. A.; Holmgren, D.; Hsu, L.; Huber, M. E.; Kamaev, O.; Kiveni, M.;
Kos, M.; Leman, S. W.; Mahapatra, R.; Mandic, V.; McCarthy, K. A.;
Mirabolfathi, N.; Moore, D.; Nelson, H.; Ogburn, R. W.; Phipps, A.;
Pyle, M.; Qiu, X.; Ramberg, E.; Rau, W.; Reisetter, A.; Saab, T.;
Sadoulet, B.; Sander, J.; Schnee, R. W.; Seitz, D. N.; Serfass, B.;
Sundqvist, K. M.; Tarka, M.; Wikus, P.; Yellin, S.; Yoo, J.; Young,
B. A.; Zhang, J.
Bibcode: 2010Sci...327.1619C
Altcode: 2009arXiv0912.3592T
Astrophysical observations indicate that dark matter constitutes most
of the mass in our universe, but its nature remains unknown. Over the
past decade, the Cryogenic Dark Matter Search (CDMS II) experiment
has provided world-leading sensitivity for the direct detection of
weakly interacting massive particle (WIMP) dark matter. The final
exposure of our low-temperature germanium particle detectors at the
Soudan Underground Laboratory yielded two candidate events, with an
expected background of 0.9 ± 0.2 events. This is not statistically
significant evidence for a WIMP signal. The combined CDMS II data
place the strongest constraints on the WIMP-nucleon spin-independent
scattering cross section for a wide range of WIMP masses and exclude
new parameter space in inelastic dark matter models.
Title: Analysis of the low-energy electron-recoil spectrum of the
CDMS experiment
Authors: Ahmed, Z.; Akerib, D. S.; Arrenberg, S.; Bailey, C. N.;
Balakishiyeva, D.; Baudis, L.; Bauer, D. A.; Beaty, J.; Brink,
P. L.; Bruch, T.; Bunker, R.; Cabrera, B.; Caldwell, D. O.;
Cooley, J.; Cushman, P.; Dejongh, F.; Dragowsky, M. R.; Duong, L.;
Figueroa-Feliciano, E.; Filippini, J.; Fritts, M.; Golwala, S. R.;
Grant, D. R.; Hall, J.; Hennings-Yeomans, R.; Hertel, S.; Holmgren, D.;
Hsu, L.; Huber, M. E.; Kamaev, O.; Kiveni, M.; Kos, M.; Leman, S. W.;
Mahapatra, R.; Mandic, V.; Moore, D.; McCarthy, K. A.; Mirabolfathi,
N.; Nelson, H.; Ogburn, R. W.; Pyle, M.; Qiu, X.; Ramberg, E.; Rau,
W.; Reisetter, A.; Saab, T.; Sadoulet, B.; Sander, J.; Schnee, R. W.;
Seitz, D. N.; Serfass, B.; Sundqvist, K. M.; Wang, G.; Wikus, P.;
Yellin, S.; Yoo, J.; Young, B. A.
Bibcode: 2010PhRvD..81d2002A
Altcode: 2009arXiv0907.1438A
We report on the analysis of the low-energy electron-recoil spectrum
from the CDMS II experiment using data with an exposure of 443.2
kg-days. The analysis provides details on the observed counting rate and
possible background sources in the energy range of 2-8.5 keV. We find
no significant excess of a peaked contribution to the total counting
rate above the background model, and compare this observation to the
recent DAMA results. In the framework of a conversion of a dark matter
particle into electromagnetic energy, our 90% confidence level upper
limit of 0.246events/kg/day at 3.15 keV is lower than the total rate
above background observed by DAMA. In absence of any specific particle
physics model to provide the scaling in cross section between NaI
and Ge, we assume a Z2 scaling. With this assumption the
observed rate in DAMA remains higher than the upper limit in CDMS. Under
the conservative assumption that the modulation amplitude is 6% of
the total rate we obtain upper limits on the modulation amplitude a
factor of ∼2 lower than observed by DAMA, constraining some possible
interpretations of this modulation.
Title: The Night Time Sun: X-Ray Observations of the Solar Twin
18 Scorpii
Authors: Coughlin, Jared; Guinan, E. F.; Engle, S. G.; DeWarf, L.;
Hall, J. C.; DePasquale, J.; Thompson, R. R.
Bibcode: 2010AAS...21542417C
Altcode: 2010BAAS...42..333C
Since the study by Porto de Mello & da Silva(1997,ApJ,482) the
nearby 5.5-mag G2V star 18 Scorpii has been considered one of the best
solar twins, being a near-perfect match to our Sun in all physical
characteristics(Teff, R, log(g), MV, metallicity,
luminosity, and chromospheric CaII H&K emissions). Also, 18 Sco has
a rotation period of PRot=22.7±0.5 days(Petit et al. 2008),
which is very close to that of the Sun. In addition, ongoing CaII
H&K observations carried out at Lowell Observatory indicate a
possible 7-11yr. activity cycle. However, until our X-ray observations
with XMM-Newton in Aug 2005, 18 Sco had never been observed in this
spectral region. The analysis of these measurements yield an X-ray
luminosity and coronal plasma temperature of LX=8±1.5ergs/s
and TCorona 1.5-2 MK. These data were taken near mid-cycle
and match very closely with those of the Sun(LX 6-30ergs/s
TCorona 2 MK). In addition to these measures, interferometric
angular diameter measures with the Palomar Testbed Interferometer yield
a stellar diameter of 0.975±0.162 R/RSun. Fitting the star's
observed properties to current evolution models indicates a mass of
M=0.98±0.05 MSun and an age of 4-5 Gyr. This age estimate
(4.4±0.4 Gyr) is in excellent agreement with an age inferred from
age-rotation-activity relations from the Sun in Time project. These
observations demonstrate that 18 Sco is a bonafide solar twin out
through the X-ray portion of the spectrum. Such a distinction makes
is a very important star to use as a proxy "Night Time” Sun for
standardization purposes, an excellent candidate for asteroseismic
studies, and as a target for searches for life-bearing terrestrial
planets. This research is supported by grants from NASA/FUSE,
NSF/RUI and by the Villanova University Research for Undergraduates
Award Program, which we gratefully acknowledge.
Title: 51 Pegasi - a planet-bearing Maunder minimum candidate
Authors: Poppenhäger, K.; Robrade, J.; Schmitt, J. H. M. M.; Hall,
J. C.
Bibcode: 2009A&A...508.1417P
Altcode: 2009arXiv0911.4862P
We observed 51 Peg, the first detected planet-bearing star, in a 55 ks
XMM-Newton pointing and in 5 ks pointings each with Chandra HRC-I and
ACIS-S. The star has a very low count rate in the XMM observation,
but is clearly visible in the Chandra images due to the detectors'
different sensitivity at low X-ray energies. This allows a temperature
estimate for 51 Peg's corona of T⪉ 1 MK; the detected ACIS-S photons
can be plausibly explained by emission lines of a very cool plasma near
200 eV. The constantly low X-ray surface flux and the flat-activity
profile seen in optical Ca II data suggest that 51 Peg is a Maunder
minimum star; an activity enhancement due to a Hot Jupiter, as proposed
by recent studies, seems to be absent. The star's X-ray fluxes in
different instruments are consistent with the exception of the HRC
Imager, which might have a larger effective area below 200 eV than
given in the calibration.
Title: The Cryogenic Dark Matter Search (CDMS) experiment: Results,
status and perspective
Authors: Mirabolfathi, N.; Ahmed, Z.; Akerib, D. S.; Arrenberg, S.;
Bailey, C. N.; Balakishiyeva, D.; Baudis, L.; Bauer, D. A.; Beaty,
J.; Brink, P. L.; Bruch, T.; Bunker, R.; Cabrera, B.; Caldwell,
D. O.; Clark, K.; Cooley, J.; Cushman, P.; Dejongh, F.; Dragowski,
M. R.; Duong, L.; Figueroa-Feliciano, E.; Filippini, J.; Fritts, M.;
Golwala, S. R.; Grant, D. R.; Hall, J.; Hennins-Yeomans, R.; Hertel,
S.; Homgren, D.; Hsu, L.; Huber, M. E.; Kamaev, O.; Kiveni, M.; Kos,
M.; Leman, S. W.; Mahapatra, R.; Mandic, V.; Moore, D.; McCarthy,
K. A.; Nelson, H.; Ogburn, R. W.; Pyle, M.; Qiu, X.; Ramberg, E.;
Rau, W.; Reisetter, A.; Saab, T.; Sadoulet, B.; Sanders, J.; Schnee,
R. W.; Seitz, D. N.; Serfass, B.; Sundqvist, K. M.; Wang, G.; Yellin,
S.; Yoo, J.; Young, B. A.
Bibcode: 2009AIPC.1185..623M
Altcode:
The Cryogenic Dark Matter Search experiment (CDMS) is using
Phonon+Ionization detectors to search for Dark Matter in the form of
Weakly Interactive Massive Particles (WIMPs). We report on new results
from the operation of CDMS five ``towers'' at Soudan underground
laboratory. With new and more massive detectors, SuperCDMS project
has been started since March 2009. We report on the current status of
SuperCDMS and its perspective.
Title: The Cryogenic Dark Matter Search (CDMS) : Present Status
and Future
Authors: Brink, P. L.; Ahmed, Z.; Akerib, D. S.; Bailey, C. N.;
Balakishiyeva, D.; Bauer, D. A.; Beaty, J.; Bunker, R.; Cabrera,
B.; Caldwell, D. O.; Cooley, J.; Do Couto E Silva, E.; Cushman, P.;
Dejongh, F.; Dragowsky, M. R.; Duong, L.; Figueroa-Feliciano, E.;
Filippini, J.; Fritts, M.; Golwala, S. R.; Grant, D. R.; Hall, J.;
Hennings-Yeomans, R.; Hertel, S.; Hojem, A.; Holmgren, D.; Hsu, L.;
Huber, M. E.; Kamaev, O.; Kos, M.; Kiveni, M.; Leman, S. W.; Mahapatra,
R.; Mandic, V.; McCarthy, K. A.; Moore, D.; Mirabolfathi, N.; Nelson,
H.; Novak, L.; Ogburn, R. W.; Pyle, M.; Qiu, X.; Ramberg, E.; Rau,
W.; Reisetter, A.; Saab, T.; Sadoulet, B.; Sander, J.; Schmitt, R.;
Schnee, R. W.; Seitz, D. N.; Serfass, B.; Sundqvist, K. M.; Tomada,
A.; Wang, G.; Wikus, P.; Yellin, S.; Yoo, J.; Young, B. A.
Bibcode: 2009AIPC.1182..260B
Altcode:
The CDMS collaboration utilizes Ge detectors for their Weakly
Interacting Massive Particle (WIMP) search at the Soudan mine,
Minnesota. The final data run of CDMS II is complete and a detector
upgrade for SuperCDMS has commenced. A SuperTower of five 1-inch
thick Ge crystals has been installed and undergoing commissioning. Its
surface-event rejection capability should allow SuperCDMS to continue to
run background free for the next proposed phases: 15 kg Ge deployment
at Soudan, and up to 150 kg Ge deployment at SNOLAB. Recent detector
advances to allow a 1 tonne Ge experiment are also discussed.
Title: Search for Axions with the CDMS Experiment
Authors: Ahmed, Z.; Akerib, D. S.; Arrenberg, S.; Bailey, C. N.;
Balakishiyeva, D.; Baudis, L.; Bauer, D. A.; Beaty, J.; Brink,
P. L.; Bruch, T.; Bunker, R.; Cabrera, B.; Caldwell, D. O.;
Cooley, J.; Cushman, P.; Dejongh, F.; Dragowsky, M. R.; Duong, L.;
Figueroa-Feliciano, E.; Filippini, J.; Fritts, M.; Golwala, S. R.;
Grant, D. R.; Hall, J.; Hennings-Yeomans, R.; Hertel, S.; Holmgren, D.;
Hsu, L.; Huber, M. E.; Kamaev, O.; Kiveni, M.; Kos, M.; Leman, S. W.;
Mahapatra, R.; Mandic, V.; Moore, D.; McCarthy, K. A.; Mirabolfathi,
N.; Nelson, H.; Ogburn, R. W.; Pyle, M.; Qiu, X.; Ramberg, E.; Rau,
W.; Reisetter, A.; Saab, T.; Sadoulet, B.; Sander, J.; Schnee, R. W.;
Seitz, D. N.; Serfass, B.; Sundqvist, K. M.; Tarka, M.; Wang, G.;
Yellin, S.; Yoo, J.; Young, B. A.
Bibcode: 2009PhRvL.103n1802A
Altcode: 2009arXiv0902.4693C
We report on the first axion search results from the Cryogenic Dark
Matter Search (CDMS) experiment at the Soudan Underground Laboratory. An
energy threshold of 2 keV for electron-recoil events allows a search for
possible solar axion conversion into photons or local galactic axion
conversion into electrons in the germanium crystal detectors. The
solar axion search sets an upper limit on the Primakov coupling
gaγγ of 2.4×10-9GeV-1 at the 95%
confidence level for an axion mass less than 0.1keV/c2. This
limit benefits from the first precise measurement of the absolute
crystal plane orientations in this type of experiment. The galactic
axion search analysis sets a world-leading experimental upper limit
on the axioelectric coupling gaēe of 1.4×10-12
at the 90% confidence level for an axion mass of 2.5keV/c2.
Title: The Activity and Variability of the Sun and Sun-Like
Stars. II. Contemporaneous Photometry and Spectroscopy of Bright
Solar Analogs
Authors: Hall, Jeffrey C.; Henry, Gregory W.; Lockwood, G. Wesley;
Skiff, Brian A.; Saar, Steven H.
Bibcode: 2009AJ....138..312H
Altcode:
We present 14 years of contemporaneous photometric and spectroscopic
observations of 28 solar analog stars, taken with the Tennessee State
University Automatic Photometric Telescopes at Fairborn Observatory
and the Solar-Stellar Spectrograph at Lowell Observatory. These
are the best observed and most nearly Sun-like of the targets in
our magnitude-limited (V <= 7.5) sample. The correlations between
luminosity and activity reveal the expected inverse activity-brightness
correlations for active stars. Strong direct correlations between
activity and brightness are not prevalent for the less active solar
age stars, but are precision limited. The Sun does not appear to
have unusually low photometric variability when compared with the
most Sun-like inactive solar analogs. We present evidence that
the activity index R'HK is not a good discriminant of
Maunder Minimum candidate stars. On the basis of a star that appears
to have transitioned from a low-variability state to a cycling
state, we investigate the regime in which stars might switch from
faculae-dominated to spot-dominated variations.
Title: A Venus Flagship Mission: Report of the Venus Science and
Technology Definition Team
Authors: Bullock, M. A.; Senske, D. A.; Balint, T. S.; Benz, A.;
Campbell, B. A.; Chassefiere, E.; Colaprete, A.; Cutts, J. A.; Glaze,
L.; Gorevan, S.; Grinspoon, D. H.; Hall, J.; Hashimoto, G. L.; Head,
J. W.; Hunter, G.; Johnson, N.; Kerzhanovich, V. V.; Kiefer, W. S.;
Kolawa, E. A.; Kremic, T.; Kwok, J.; Limaye, S. S.; Mackwell, S. J.;
Marov, M. Y.; Ocampo, A.; Schubert, G.; Stofan, E. R.; Svedhem, H.;
Titov, D. V.; Treiman, A. H.
Bibcode: 2009LPI....40.2410B
Altcode:
The Venus STDT has defined the goals, objectives, mission architecture,
science investigations and payload for a Flagship-class mission to
Venus. The mission puts advanced exploration capabilities in orbit,
in the atmosphere, and on the surface.
Title: The Cryogenic Dark Matter Search (CDMS) experiment: Results
and prospects
Authors: Brink, P. L.; Ahmed, Z.; Akerib, D. S.; Bailey, C. N.; Bauer,
D. A.; Beaty, J.; Bunker, R.; Burke, S.; Cabrera, B.; Caldwell, D. O.;
Cooley, J.; Cushman, P.; DeJongh, F.; Dragowsky, M. R.; Duong, L.;
Figueroa-Feliciano, E.; Filippini, J.; Fritts, M.; Golwala, S. R.;
Grant, D. R.; Hall, J.; Hennings-Yeomans, R.; Hertel, S.; Holmgren,
D.; Huber, M. E.; Mahapatra, R.; Mandic, V.; McCarthy, K. A.;
Mirabolfathi, N.; Nelson, H.; Novak, L.; Ogburn, R. W.; Pyle, M.;
Qiu, X.; Ramberg, E.; Rau, W.; Reisetter, A.; Saab, T.; Sadoulet,
B.; Sander, J.; Schmitt, R.; Schnee, R. W.; Seitz, D. N.; Serfass,
B.; Sirois, A.; Sundqvist, K. M.; Tomada, A.; Wang, G.; Yellin, S.;
Yoo, J.; Young, B. A.
Bibcode: 2009JPhCS.150a2006B
Altcode:
Weakly Interacting Massive Particles (WIMPs) are a strong candidate for
the Cold Dark Matter of the Universe. CDMS-II is a direct-search WIMP
search experiment, operating at 50 mK and housed at the Soudan mine,
Minnesota. The 250 gram Ge detectors utilize athermal phonon sensors
where tungsten transition edge sensors are operated in negative
electrothermal feedback. The search at Soudan is ongoing with an
expected final reach of CDMS-II by the end of 2008 of a WIMP-nucleon
cross-section sensitivity of 2.1 x10-44 cm2,
at a WIMP mass of 60 GeV/c2. To proceed further, we have
proposed the SuperCDMS program.
Title: The Stars as a Sun: Secular Variations of Cycling and
Non-Cycling Stars
Authors: Hall, Jeffrey C.; Giampapa, Mark S.; Henry, Gregory W.;
Lean, Judith L.; Saar, Steven H.; Soderblom, David R.
Bibcode: 2009astro2010S.111H
Altcode:
No abstract at ADS
Title: Progress and Key Projects of the Discovery Channel Telescope
at Lowell Observatory
Authors: Hall, Jeffrey C.; Smith, B.; Chylek, T.; DeGroff, B.;
Lotz, P.; Venetiou, A. J.; Westcott, K.; Bida, T.; Dunham, E. W.;
Zoonematkermani, S.; Collins, P.; Millis, R. L.
Bibcode: 2009AAS...21347412H
Altcode: 2009BAAS...41R.429H
The Discovery Channel Telescope (DCT) is a 4.2-m instrument under
construction 35 miles southeast of Flagstaff, Arizona. All first
light components of the telescope are actively being worked, with
commissioning scheduled for early 2011. Planned first generation
instruments include an imager, IR spectrograph, and optical spectrograph
at the RC focus. The design also provides for observations at prime and
Nasmyth foci. Research and results from the telescope will be widely
disseminated through Lowell Observatory's partnership with Discovery
Communications. I will describe the design and construction status of
the telescope, as well as the key projects identified for the initial
science operations.
Title: Search for Weakly Interacting Massive Particles with the First
Five-Tower Data from the Cryogenic Dark Matter Search at the Soudan
Underground Laboratory
Authors: Ahmed, Z.; Akerib, D. S.; Arrenberg, S.; Attisha, M. J.;
Bailey, C. N.; Baudis, L.; Bauer, D. A.; Beaty, J.; Brink, P. L.;
Bruch, T.; Bunker, R.; Burke, S.; Cabrera, B.; Caldwell, D. O.; Cooley,
J.; Cushman, P.; Dejongh, F.; Dragowsky, M. R.; Duong, L.; Emes, J.;
Figueroa-Feliciano, E.; Filippini, J.; Fritts, M.; Gaitskell, R. J.;
Golwala, S. R.; Grant, D. R.; Hall, J.; Hennings-Yeomans, R.; Hertel,
S.; Holmgren, D.; Huber, M. E.; Mahapatra, R.; Mandic, V.; McCarthy,
K. A.; Mirabolfathi, N.; Nelson, H.; Novak, L.; Ogburn, R. W.; Pyle,
M.; Qiu, X.; Ramberg, E.; Rau, W.; Reisetter, A.; Saab, T.; Sadoulet,
B.; Sander, J.; Schmitt, R.; Schnee, R. W.; Seitz, D. N.; Serfass,
B.; Sirois, A.; Sundqvist, K. M.; Tarka, M.; Tomada, A.; Wang, G.;
Yellin, S.; Yoo, J.; Young, B. A.
Bibcode: 2009PhRvL.102a1301A
Altcode: 2008arXiv0802.3530C
We report results from the Cryogenic Dark Matter Search at the Soudan
Underground Laboratory (CDMS II) featuring the full complement
of 30 detectors. A blind analysis of data taken between October
2006 and July 2007 sets an upper limit on the weakly interacting
massive particle (WIMP) nucleon spin-independent cross section of
6.6×10-44cm2 (4.6×10-44cm2
when combined with previous CDMS II data) at the 90% confidence
level for a WIMP mass of 60GeV/c2. This achieves the best
sensitivity for dark matter WIMPs with masses above 44GeV/c2,
and significantly restricts the parameter space for some favored
supersymmetric models.
Title: Section on Prospects for Dark Matter Detection of the White
Paper on the Status and Future of Ground-Based TeV Gamma-Ray Astronomy
Authors: Buckley, J.; Baltz, E. A.; Bertone, G.; Byrum, K.; Fegan, S.;
Ferrer, F.; Gondolo, P.; Hall, J.; Hooper, D.; Horan, D.; Koushiappas,
S.; Krawczynski, H.; LeBohec, S.; Profumo, S.; Silk, J.; Tait, T.;
Vassiliev, V.; Wagner, R.; Wakely, S.; Wood, M.; Zaharijas, G.
Bibcode: 2008arXiv0812.0795B
Altcode:
This is a report on the findings of the dark matter science
working group for the white paper on the status and future of TeV
gamma-ray astronomy. The white paper was commissioned by the American
Physical Society, and the full white paper can be found on astro-ph
(arXiv:0810.0444). This detailed section discusses the prospects
for dark matter detection with future gamma-ray experiments, and the
complementarity of gamma-ray measurements with other indirect, direct
or accelerator-based searches. We conclude that any comprehensive
search for dark matter should include gamma-ray observations, both
to identify the dark matter particle (through the charac- teristics
of the gamma-ray spectrum) and to measure the distribution of dark
matter in galactic halos.
Title: A Venus Flagship Mission: Exploring a World of Contrasts
Authors: Senske, D.; Bullock, M.; Balint, T.; Benz, A.; Campbell,
B.; Chassefiere, E.; Colaprete, A.; Cutts, J.; Glaze, L.; Gorevan,
S.; Grinspoon, D.; Hall, J.; Hasimoto, G.; Head, J.; Hunter, G.;
Johnson, N.; Kiefer, W.; Kolawa, E.; Kremic, T.; Kwok, J.; Limaye,
S.; Mackwell, S.; Marov, M.; Peterson, C.; Schubert, G.; Spilker,
T.; Stofan, E.; Svedhem, H.; Titov, D.; Treiman, A.
Bibcode: 2008AGUFM.P22A..08S
Altcode:
Results from past missions and the current Venus Express Mission show
that Venus is a world of contrasts, providing clear science drivers
for renewed exploration of this planet. In early 2008, NASA's Science
Mission Directorate formed a Science and Technology Definition Team
(STDT) to formulate science goals and objectives, mission architecture
and a technology roadmap for a flagship class mission to Venus. This
3- to 4 billon mission, to launch in the post 2020 timeframe, should
revolutionize our understanding of how climate works on terrestrial
planets, including the close relationship between volcanism, tectonism,
the interior, and the atmosphere. It would also more clearly elucidate
the geologic history of Venus, including the existence and persistence
of an ancient ocean. Achieving these objectives will provide a basis
to understand the habitability of extra solar terrestrial planets. To
address a broad range of science questions this mission will be composed
of flight elements that include an orbiter that is highlighted by an
interferometric SAR to provide surface topographic and image information
at scales one to two orders of magnitude greater than that achieved by
any previous spacecraft to Venus. Two balloons with a projected lifetime
of weeks will probe the structure and dynamics of the atmosphere at an
altitude of 50 to 70-km. In addition, two descent probes will collect
data synergistic to that from the balloon and analyze the geochemistry
of surface rocks over a period of hours. The technology road map
focuses on key areas of science instruments and enabling engineering
to provide greater in situ longevity in the hostile Venus environment.
Title: Stellar Chromospheric Activity
Authors: Hall, Jeffrey C.
Bibcode: 2008LRSP....5....2H
Altcode:
The Sun, stars similar to it, and many rather dissimilar to it,
have chromospheres, regions classically viewed as lying above the
brilliant photosphere and characterized by a positive temperature
gradient and a marked departure from radiative equilibrium. Stellar
chromospheres exhibit a wide range of phenomena collectively called
activity, stemming largely from the time evolution of their magnetic
fields and the mass flux and transfer of radiation through the complex
magnetic topology and the increasingly optically thin plasma of the
outer stellar atmosphere. In this review, I will (1) outline the
development of our understanding of chromospheric structure from
1960 to the present, (2) discuss the major observational programs
and theoretical lines of inquiry, (3) review the origin and nature of
both solar and stellar chromospheric activity and its relationship to,
and effect on, stellar parameters including total energy output, and
(4) summarize the outstanding problems today.
Title: The X-ray cycle in the solar-type star HD 81809. XMM-Newton
observations and implications for the coronal structure
Authors: Favata, F.; Micela, G.; Orlando, S.; Schmitt, J. H. M. M.;
Sciortino, S.; Hall, J.
Bibcode: 2008A&A...490.1121F
Altcode: 2008arXiv0806.2279F
Context: The 11-yr cycle is the best known manifestation of the Sun's
activity. While chromospheric cycles have been studied in a number of
solar-like stars, very little is known about how these are reflected
in the cyclical behavior of the coronal X-ray emission in stars other
than the Sun.
Aims: Our long-term XMM-Newton program of long-term
monitoring of a solar-like star with a well-studied chromospheric cycle,
HD 81809, aims to study whether an X-ray cycle is present, along with
studying its characteristics and its relation to the chromospheric
cycle.
Methods: Regular observations of HD 81809 were performed
with XMM-Newton, spaced by 6 months from 2001 to 2007. We studied
the variations in the resulting coronal luminosity and temperature,
and compared them with the chromospheric Ca ii variations. We also
modeled the observations in terms of a mixture of active regions,
using a methodology originally developed to study the solar corona.
Results: Our observations show a well-defined cycle with an amplitude
exceeding 1 dex and an average luminosity approximately one order of
magnitude higher than in the Sun. The behavior of the corona of HD
81809 can be modeled well in terms of varying coverage of solar-like
active regions, with a larger coverage than for the Sun, showing it
to be compatible with a simple extension of the solar case.
Title: NASA's Venus Science and Technology Definition Team: A Flagship
Mission to Venus
Authors: Bullock, Mark Alan; Senske, D. A.; Balint, T. S.; Campbell,
B. A.; Chassefiere, E.; Colaprete, A.; Cutts, J. A.; Glaze, L.;
Gorevan, S.; Grinspoon, D. H.; Hall, J.; Hartford, W.; Hashimoto,
G. L.; Head, J. W.; Hunter, G.; Johnson, N.; Kiefer, W. S.; Kolawa,
E. A.; Kremic, T.; Kwok, J.; Limaye, S. S.; Mackwell, S. J.; Marov,
M. Y.; Ocampo, A.; Schubert, G.; Stofan, E. R.; Svedhem, H.; Titov,
D. V.; Treiman, A. H.
Bibcode: 2008DPS....40.3208B
Altcode: 2008BAAS...40R.452B
The Venus Science and Technology Definition Team (STDT) was formed
by NASA to look at science objectives, mission architecture, science
investigations, and instrument payload for a Flagship-class mission to
Venus. This $3-4B mission, to launch in the 2020-2025 timeframe, should
revolutionize our understanding of how climate works on terrestrial
planets, including the close relationship between volcanism, tectonism,
the interior, and the atmosphere. It would also be capable of resolving
the geologic history of Venus, including the existence and persistence
of an ancient ocean. Achieving all these objectives will be necessary
to understand the habitability of extrasolar terrestrial planets that
should be detected in the next few years. The Venus STDT is comprised of
scientists and engineers from the United States, the Russian Federation,
France, Germany, the Netherlands, and Japan. The team began work in
January 2008, gave an interim report at NASA headquarters in May,
and will deliver a final report in December 2008. The Venus STDT will
also produce a technology roadmap to identify crucial investments to
meet the unique challenges of in situ Venus exploration. We will
discuss the mission architecture and payload that have been designed to
address the science objectives, and the methods we used. Most of the
science objectives in the latest VEXAG white paper can be addressed
by a Venus Flagship mission, and equally importantly, NASA can fly a
large mission to another Earth-sized planet with the explicit intention
of better understanding our own.
Title: A Search for Dark Matter Annihilation with the Whipple 10
m Telescope
Authors: Wood, M.; Blaylock, G.; Bradbury, S. M.; Buckley, J. H.;
Byrum, K. L.; Chow, Y. C. K.; Cui, W.; de la Calle Perez, I.; Falcone,
A. D.; Fegan, S. J.; Finley, J. P.; Grube, J.; Hall, J.; Hanna, D.;
Holder, J.; Horan, D.; Humensky, T. B.; Kieda, D. B.; Kildea, J.;
Konopelko, A.; Krawczynski, H.; Krennrich, F.; Lang, M. J.; LeBohec,
S.; Nagai, T.; Ong, R. A.; Perkins, J. S.; Pohl, M.; Quinn, J.; Rose,
H. J.; Sembroski, G. H.; Vassiliev, V. V.; Wagner, R. G.; Wakely,
S. P.; Weekes, T. C.; Weinstein, A.
Bibcode: 2008ApJ...678..594W
Altcode: 2008arXiv0801.1708W
We present observations of the dwarf galaxies Draco and Ursa Minor, the
Local Group galaxies M32 and M33, and the globular cluster M15 conducted
with the Whipple 10 m gamma-ray telescope to search for the gamma-ray
signature of self-annihilating weakly interacting massive particles
(WIMPs), which may constitute astrophysical dark matter (DM). We
review the motivations for selecting these sources based on their
unique astrophysical environments and report the results of the data
analysis that produced upper limits on the excess rate of gamma rays for
each source. We consider models for the DM distribution in each source
based on the available observational constraints and discuss possible
scenarios for the enhancement of the gamma-ray luminosity. Limits on
the thermally averaged product of the total self-annihilation cross
section and velocity of the WIMP, langleσυrangle , are derived
using conservative estimates for the magnitude of the astrophysical
contribution to the gamma-ray flux. Although these limits do not
constrain predictions from the currently favored theoretical models
of supersymmetry (SUSY), future observations with VERITAS will probe
a larger region of the WIMP parameter phase space, langleσυrangle ,
and WIMP particle mass (mχ).
Title: First observation of planet-induced X-ray emission: The system
HD 179949
Authors: Saar, S. H.; Cuntz, M.; Kashyap, V. L.; Hall, J. C.
Bibcode: 2008IAUS..249...79S
Altcode: 2007IAUS..249...79S; 2007arXiv0712.3270S
We present the first observation of planet-induced stellar X-ray
activity, identified for the HD 179949 system, using Chandra /
ACIS-S. The HD 179949 system consists of a close-in giant planet
orbiting an F9 V star. Previous ground-based observations already showed
enhancements in Ca II K in phase with the planetary orbit. We find an
30% increase in the X-ray flux over quiescent levels coincident with the
phase of the Ca II enhancements. There is also a trend for the emission
to be hotter at increased fluxes, confirmed by modeling, showing the
enhancement at 1 keV compared to 0.4 keV for the background star.
Title: First results from VERITAS
Authors: Hanna, D.; Acciari, V. A.; Amini, R.; Badran, H. M.; Blaylock,
G.; Bradbury, S. M.; Buckley, J. H.; Bugaev, V.; Butt, Y.; Byrum,
K. L.; Celik, O.; Cesarini, A.; Ciupik, L.; Chow, Y. C. K.; Cogan, P.;
Colin, P.; Cui, W.; Daniel, M. K.; Dowdall, C.; Dowkontt, P.; Duke,
C.; Ergin, T.; Falcone, A. D.; Fegan, D. J.; Fegan, S. J.; Finley,
J. P.; Fortin, P.; Fortson, L. F.; Gall, D.; Gibbs, K.; Gillanders,
G.; Glidewell, O. J.; Grube, J.; Guenette, R.; Gyuk, G.; Hall, J.;
Hays, E.; Holder, J.; Horan, D.; Hughes, S. B.; Hui, C. M.; Humensky,
T. B.; Imran, A.; Kaaret, P.; Kenny, G. E.; Kertzman, M.; Kieda, D.;
Kildea, J.; Konopelko, A.; Krawczynski, H.; Krennrich, F.; Lang,
M. J.; Lebohec, S.; Lee, K.; Manseri, H.; McCann, A.; McCutcheon,
M.; Millis, J.; Moriarty, P.; Mukherjee, R.; Nagai, T.; Niemiec, J.;
Ogden, P. A.; Ong, R. A.; Pandel, D.; Perkins, J. S.; Pizlo, F.; Pohl,
M.; Quinn, J.; Ragan, K.; Reynolds, P. T.; Roache, E.; Rose, H. J.;
Schroedter, M.; Sembroski, G. H.; Smith, A. W.; Steele, D.; Swordy,
S. P.; Syson, A.; Toner, J. A.; Valcarcel, L.; Vassiliev, V. V.;
Wagner, R.; Wakely, S. P.; Ward, J. E.; Weekes, T. C.; Weinstein,
A.; White, R. J.; Williams, D. A.; Wissel, S. A.; Wood, M.; Zitzer, B.
Bibcode: 2008NIMPA.588...26H
Altcode:
VERITAS is an array of four, 12-m-diameter, Cherenkov telescopes,
designed to explore the very-high-energy gamma-ray sky in the energy
band between 100 GeV and 50 TeV. Its construction and commissioning
have occurred over the past two years and the array has been taking
scientific data with three or more telescopes since November 2006. We
present results from observations made with VERITAS during the
past observing season, including new results on the distant blazar
1ES1218+304, the active galaxy M87 and the high-mass X-ray binary
system LS I +61 303. We also describe the plans in place for the coming
observing seasons.
Title: VERITAS: Status and Latest Results
Authors: Maier, G.; Acciari, V. A.; Amini, R.; Blaylock, G.; Bradbury,
S. M.; Buckley, J. H.; Bugaev, V.; Butt, Y.; Byrum, K. L.; Celik, O.;
Cesarini, A.; Ciupik, L.; Chow, Y. C. K.; Cogan, P.; Colin, P.; Cui,
W.; Daniel, M. K.; Dowdall, C.; Dowkontt, P.; Duke, C.; Ergin, T.;
Falcone, A. D.; Fegan, D. J.; Fegan, S. J.; Finley, J. P.; Fotin,
P.; Fortson, L. F.; Gall, D.; Gibbs, K.; Gillanders, G.; Grube,
J.; Guenette, R.; Gyuk, G.; Hall, J.; Hanna, D.; Hays, E.; Holder,
J.; Horan, D.; Hughes, S. B.; Hui, C. M.; Humensky, T. B.; Imran,
A.; Kaaret, P.; Kenny, G. E.; Kertzman, M.; Kieda, D.; Kildea, J.;
Konopelko, A.; Krawczynski, H.; Krennrich, F.; Lang, M. J.; LeBohec,
S.; Lee, K.; Manseri, H.; McCann, A.; McCutcheron, M.; Millis, J.;
Moriarty, P.; Mukherjee, R.; Nagai T.; Niemiec, J.; Ogden, P. A.;
Ong, R. A.; Pandel, D.; Perkins, J. S.; Pizlo, F.; Pohl, M.; Quinn,
J.; Ragan, K.; Reynolds, P. T.; Roache, E.; Rose, H. J.; Schroedter,
M.; Sembroski, G. H.; Smith, A. W.; Steele, D.; Swordy, S. P.;
Syson, A.; Toner, J. A.; Valcarcel, L.; Vassiliev, V. V.; Wagner,
R.; Wakely, S. P.; Ward, J. E.; Weeks, T. C.; Weinstein, A.; White,
R. J.; Williams, D. A.; Wissel, S. A.; Wood, M.; Zitzer, B.
Bibcode: 2008ICRC....3.1457M
Altcode: 2008ICRC...30c1457M; 2007arXiv0709.3654M
VERITAS is an atmospheric Cherenkov telescope array designed to study
astrophysical sources of very high energy gamma radiation. Located in
southern Arizona, USA, the array consists of four 12-m diameter imaging
Cherenkov telescopes. All four telescopes have been deployed at the
basecamp of the Whipple Observatory and they became fully operational
in early 2007. This paper describes the operational status of VERITAS,
outlines the initial performance parameters of the instrument, and
presents the latest results that have been obtained.
Title: The Whipple Observatory 10 m gamma-ray telescope, 1997 2006
Authors: Kildea, J.; Atkins, R. W.; Badran, H. M.; Blaylock, G.;
Bond, I. H.; Bradbury, S. M.; Buckley, J. H.; Carter-Lewis, D. A.;
Celik, O.; Chow, Y. C. K.; Cui, W.; Cogan, P.; Daniel, M. K.; de la
Calle Perez, I.; Dowdall, C.; Duke, C.; Falcone, A. D.; Fegan, D. J.;
Fegan, S. J.; Finley, J. P.; Fortson, L. F.; Gall, D.; Gillanders,
G. H.; Grube, J.; Gutierrez, K. J.; Hall, J.; Hall, T. A.; Holder,
J.; Horan, D.; Hughes, S. B.; Jordan, M.; Jung, I.; Kenny, G. E.;
Kertzman, M.; Knapp, J.; Konopelko, A.; Kosack, K.; Krawczynski, H.;
Krennrich, F.; Lang, M. J.; LeBohec, S.; Lloyd-Evans, J.; Millis, J.;
Moriarty, P.; Nagai, T.; Ogden, P. A.; Ong, R. A.; Perkins, J. S.;
Petry, D.; Pizlo, F.; Pohl, M.; Quinn, J.; Quinn, M.; Rebillot, P. F.;
Rose, H. J.; Schroedter, M.; Sembroski, G. H.; Smith, A. W.; Syson,
A.; Toner, J. A.; Valcarcel, L.; Vassiliev, V. V.; Wakely, S. P.;
Weekes, T. C.; White, R. J.
Bibcode: 2007APh....28..182K
Altcode:
Details are presented of the Whipple Observatory's 10 m atmospheric
Cherenkov telescope and camera, as it evolved during the period 1997
until 2006. The design of the telescope and camera's optical and
electronic systems is discussed together with a detailed description
of the four-stage GRANITE (Gamma-RAy New Imaging TElescope) upgrade
program, undertaken during the same time period. The objective of the
upgrade was to improve the telescope's sensitivity for the detection
of very-high-energy gamma-rays. Results from the program are provided
and are briefly discussed in the context of the design of VERITAS.
Title: Development of bubble chambers with enhanced stability and
sensitivity to low-energy nuclear recoils
Authors: Bolte, W. J.; Collar, J. I.; Crisler, M.; Hall, J.; Holmgren,
D.; Nakazawa, D.; Odom, B.; O'Sullivan, K.; Plunkett, R.; Ramberg,
E.; Raskin, A.; Sonnenschein, A.; Vieira, J. D.
Bibcode: 2007NIMPA.577..569B
Altcode: 2005astro.ph..3398B
The viability of using Bubble Chambers as dark matter particle detectors
is considered. Techniques leading to the enhanced chamber stability
needed for this new application are described in detail. Prototype
trials show that sensitivity to the low-energy nuclear recoils
induced by Weakly Interacting Massive Particles (WIMP) is possible in
conditions of extreme insensitivity to minimum ionizing backgrounds. An
understanding of detector response is demonstrated using existing
theoretical models. We briefly comment on the prospects for detection
of supersymmetric dark matter with large CF3I chambers.
Title: The Sun-like Activity of the Solar Twin 18 Scorpii
Authors: Hall, Jeffrey C.; Henry, Gregory W.; Lockwood, G. Wesley
Bibcode: 2007AJ....133.2206H
Altcode: 2007astro.ph..3450H
We present the results of 10 yr of complementary spectroscopic and
photometric observations of the solar twin 18 Scorpii. We show that
over the course of its ~7 yr chromospheric activity cycle, 18 Sco's
brightness varies in the same manner as the Sun's and with a likely
total brightness variation of 0.09%, similar to the 0.1% decadal
variation in the total solar irradiance.
Title: Observations of the Unidentified TeV γ-Ray Source TeV
J2032+4130 with the Whipple Observatory 10 m Telescope
Authors: Konopelko, A.; Atkins, R. W.; Blaylock, G.; Buckley, J. H.;
Butt, Y.; Carter-Lewis, D. A.; Celik, O.; Cogan, P.; Chow, Y. C. K.;
Cui, W.; Dowdall, C.; Ergin, T.; Falcone, A. D.; Fegan, D. J.; Fegan,
S. J.; Finley, J. P.; Fortin, P.; Gillanders, G. H.; Gutierrez, K. J.;
Hall, J.; Hanna, D.; Horan, D.; Hughes, S. B.; Humensky, T. B.; Imran,
A.; Jung, I.; Kaaret, P.; Kenny, G. E.; Kertzman, M.; Kieda, D. B.;
Kildea, J.; Knapp, J.; Kosack, K.; Krawczynski, H.; Krennrich, F.;
Lang, M. J.; LeBohec, S.; Moriarty, P.; Mukherjee, R.; Nagai, T.; Ong,
R. A.; Perkins, J. S.; Pohl, M.; Ragan, K.; Reynolds, P. T.; Rose,
H. J.; Sembroski, G. H.; Schrödter, M.; Smith, A. W.; Steele, D.;
Syson, A.; Swordy, S. P.; Toner, J. A.; Valcarcel, L.; Vassiliev,
V. V.; Wagner, R. G.; Wakely, S. P.; Weekes, T. C.; White, R. J.;
Williams, D. A.; Zitzer, B.; VERITAS Collaboration
Bibcode: 2007ApJ...658.1062K
Altcode: 2006astro.ph.11730K
We report on observations of the sky region around the unidentified
TeV γ-ray source (TeV J2032+4130) carried out with the Whipple
Observatory 10 m atmospheric Cerenkov telescope for a total
of 65.5 hr between 2003 and 2005. The standard two-dimensional
analysis developed by the Whipple collaboration for a stand-alone
telescope reveals an excess in the field of view at a pretrial
significance level of 6.1 σ. The measured position of this
excess is α=20h32m27s,
δ=41deg39'17'' (J2000.0). The
estimated integral flux for this γ-ray source is about 8% of the Crab
Nebula flux. The data are consistent with a pointlike source. Here
we present a detailed description of the standard two-dimensional
analysis technique used for the analysis of data taken with the Whipple
Observatory 10 m telescope and the results for the TeV J2032+4130
campaign. We include a short discussion of the physical mechanisms that
may be responsible for the observed γ-ray emission, based on possible
association with known astrophysical objects, in particular, Cygnus OB2.
Title: The Activity and Variability of the Sun and Sun-like
Stars. I. Synoptic Ca II H and K Observations
Authors: Hall, Jeffrey C.; Lockwood, G. W.; Skiff, Brian A.
Bibcode: 2007AJ....133..862H
Altcode:
Synoptic measurements of activity in Sun-like stars have been
performed continuously since 1966, and the largest set comes from the
Mount Wilson HK project, in the form of the well-known S index. We
have been monitoring the activity and variability of the Sun and a
large sample of Sun-like stars, in terms of S and absolute flux,
since 1994 with the Solar-Stellar Spectrograph (SSS) at Lowell
Observatory. Directly inspired by the similar long-term program at
Mount Wilson Observatory, the SSS incorporates both an HK spectrograph
and an echelle for visible and far-red observations. This is the first
of three papers presenting the results of some 20,000 observations
of the Sun and Sun-like stars with the SSS. In this paper we describe
our program, review the calibration of solar and stellar fluxes to S
and the chromospheric emission fraction R'HK, compare our
derived stellar activity measures to those from other programs, and
discuss the broad characteristics of the activity and variability in
our target set, with particular attention to good solar analogs and
noncycling stars. In subsequent papers we will discuss the echelle
data and present detailed examinations of stars of particular interest.
Title: Very High Energy Observations of Gamma-Ray Burst Locations
with the Whipple Telescope
Authors: Horan, D.; Atkins, R. W.; Badran, H. M.; Blaylock, G.;
Bradbury, S. M.; Buckley, J. H.; Byrum, K. L.; Celik, O.; Chow,
Y. C. K.; Cogan, P.; Cui, W.; Daniel, M. K.; de la Calle Perez, I.;
Dowdall, C.; Falcone, A. D.; Fegan, D. J.; Fegan, S. J.; Finley,
J. P.; Fortin, P.; Fortson, L. F.; Gillanders, G. H.; Grube, J.;
Gutierrez, K. J.; Hall, J.; Hanna, D.; Holder, J.; Hughes, S. B.;
Humensky, T. B.; Kenny, G. E.; Kertzman, M.; Kieda, D. B.; Kildea,
J.; Krawczynski, H.; Krennrich, F.; Lang, M. J.; LeBohec, S.; Maier,
G.; Moriarty, P.; Nagai, T.; Ong, R. A.; Perkins, J. S.; Petry,
D.; Quinn, J.; Quinn, M.; Ragan, K.; Reynolds, P. T.; Rose, H. J.;
Schroedter, M.; Sembroski, G. H.; Steele, D.; Swordy, S. P.; Toner,
J. A.; Valcarcel, L.; Vassiliev, V. V.; Wagner, R. G.; Wakely, S. P.;
Weekes, T. C.; White, R. J.; Williams, D. A.
Bibcode: 2007ApJ...655..396H
Altcode: 2007astro.ph..1281H
Gamma-ray burst (GRB) observations at very high energies (VHE;
E>100 GeV) can impose tight constraints on some GRB emission
models. Many GRB afterglow models predict a VHE component similar
to that seen in blazars and plerions, in which the GRB spectral
energy distribution has a double-peaked shape extending into the VHE
regime. VHE emission coincident with delayed X-ray flare emission has
also been predicted. GRB follow-up observations have had high priority
in the observing program at the Whipple 10 m gamma-ray telescope, and
GRBs will continue to be high-priority targets as the next-generation
observatory, VERITAS, comes online. Upper limits on the VHE emission
at late times (>~4 hr) from seven GRBs observed with the Whipple
Telescope are reported here.
Title: Time Series Observations of UX Ursae Majoris
Authors: Alexander, W. R.; Hall, J.; Nelson, T.; Miller, D.
Bibcode: 2006JAVSO..34..276A
Altcode:
No abstract at ADS
Title: Coronal activity cycles in 61 Cygni
Authors: Hempelmann, A.; Robrade, J.; Schmitt, J. H. M. M.; Favata,
F.; Baliunas, S. L.; Hall, J. C.
Bibcode: 2006A&A...460..261H
Altcode:
Context: .While the existence of stellar analogues of the 11 years
solar activity cycle is proven for dozens of stars from optical
observations of chromospheric activity, the observation of clearly
cyclical coronal activity is still in its infancy.
Aims: .In
this paper, long-term X-ray monitoring of the binary 61 Cygni is used
to investigate possible coronal activity cycles in moderately active
stars.
Methods: .We are monitoring both stellar components, a K5V
(A) and a K7V (B) star, of 61 Cyg with XMM-Newton. The first four years
of these observations are combined with ROSAT HRI observations of an
earlier monitoring campaign. The X-ray light curves are compared with
the long-term monitoring of chromospheric activity, as measured by the
Mt.Wilson CaII H+K S-index.
Results: .Besides the observation
of variability on short time scales, long-term variations of the X-ray
activity are clearly present. For 61 Cyg A we find a coronal cycle
which clearly reflects the well-known and distinct chromospheric
activity cycle. The changes of coronal properties during the cycle
resemble the solar behaviour. The coronal activity of 61 Cyg B also
follows the chromospheric variability, although a pronounced sinusoidal
chromospheric cycle of large amplitude is not noticeable. This is also
reflected in the XMM-Newton observations with a rather complex long-term
variability during that time.
Conclusions: .61 Cyg A is the
first star where a persistent coronal activity cycle has been observed.
Title: Time Series Observations of UX Ursae Majoris.
Authors: Alexander, W. R.; Hall, J.; Nelson, T.; Miller, D.
Bibcode: 2006JAVSO..34R.276A
Altcode:
No abstract at ADS
Title: A Survey of Chromospheric Activity in the Solar-Type Stars
in the Open Cluster M67
Authors: Giampapa, Mark S.; Hall, Jeffrey C.; Radick, Richard R.;
Baliunas, Sallie L.
Bibcode: 2006ApJ...651..444G
Altcode: 2006astro.ph..7313G
We present the results of a spectroscopic survey of the Ca II H and K
core strengths in a sample of 60 solar-type stars that are members of
the solar-age and solar-metallicity open cluster M67. We adopt the HK
index, defined as the summed H+K core strengths in 1 Å bandpasses
centered on the H and K lines, respectively, as a measure of the
chromospheric activity that is present. We compare the distribution of
mean HK index values for the M67 solar-type stars with the variation
of this index as measured for the Sun during the contemporary solar
cycle. We find that the stellar distribution in our HK index is broader
than that for the solar cycle. Approximately 17% of the M67 Sun-like
stars exhibit average HK indices that are less than solar minimum. About
7%-12% are characterized by relatively high activity in excess of solar
maximum values, while 72%-80% of the solar analogs exhibit Ca II H+K
strengths within the range of the modern solar cycle. The ranges given
reflect uncertainties in the most representative value of the maximum
in the HK index to adopt for the solar cycle variations observed
during the period AD 1976-2004. Thus, ~20%-30% of our homogeneous
sample of Sun-like stars have mean chromospheric H+K strengths that
are outside the range of the contemporary solar cycle. Any cycle-like
variability that is present in the M67 solar-type stars appears to be
characterized by periods greater than ~6 yr. Finally, we estimate a mean
chromospheric age for M67 in the range of 3.8-4.3 Gyr. The results
presented herein are based on data obtained at the WIYN telescope and
at the McMath-Pierce Solar Telescope. The WIYN Observatory is a joint
facility of the University of Wisconsin-Madison, Indiana University,
Yale University, and the National Optical Astronomy Observatory. The
McMath-Pierce Solar Telescope Facility is operated by the National
Solar Observatory for the National Science Foundation. This paper is
WIYN Open Cluster Study XXVIII in the series.
Title: Deployment of the VERITAS observatory
Authors: LeBohec, S.; Atkins, R. W.; Badran, H. M.; Blaylock, G.;
Bond, I. H.; Boyle, P. J.; Bradbury, Sm; Buckley, J. H.; Carter-Lewis,
Da; Celik, O.; Chow, Y. C. K.; Cogan, P.; P, W. Cu; Daniel, M. K.;
de la Calle Perez, I.; Dowdall; Dowkontt, P.; Duke, C.; Ergin, T.;
Falcone, A. D.; Fegan, D. J.; Fegan, S. J.; Finley, J. P.; Fortin,
P.; Fortson, L.; Gammell, S.; Gibbs, K.; Gillanders, G. H.; Grube, J.;
Hall, J.; Hanna, D.; Hays, E.; Holder, J.; Horana, D.; Hughes, S. B.;
Humensky, T. B.; Kaaret, P.; Kenny, G. E.; Kertzmann, M.; Kieda, D.;
Kildea, J.; Knapp, J.; Kosack, K.; Krawczynski, H.; Krennrich, F.;
Lang, M. J.; Linton, E.; Lloyd-Evans, J.; Maier, G.; Manseri, H.;
Milovanovic, A.; Moriarty, P.; Mukherjee, R.; Nagai, T. N.; Ogden,
P. A.; Olevitch, M.; Ong, R. A.; Perkins, J. S.; Petry, D.; Pizlo, F.;
Pohl, M.; Power-Mooney, B.; Quinn, J.; Quinn, M.; Ragan, K.; Reynolds,
P. T.; Rebillot, P.; Rose, H. J.; Schroedter, M.; Sembroski, G. H.;
Steele, D.; Swordy, S. P.; Syson, A.; Valcarcel, L.; Vassiliev, V. V.;
Wagner, R. G.; Wakely, S. P.; Walker, G.; Weekes, T. C.; White, R. J.;
Williams, D. A.; Zweerink, J.
Bibcode: 2006JPhCS..47..232L
Altcode:
The Very Energetic Radiation Imaging Telescope Array System (VERITAS)
being constructed in Southern Arizona consists of an array of four
Atmospheric Cherenkov 12m Telescopes designed to observe astrophysical
gamma rays in the energy range from 100 GeV to tens of TeV. A first
telescope has been in operation on a temporary site since the end
of 2004 and meets all specifications. The second is being installed
on the same site, 85m from the first, in order to test stereoscopic
capabilities. The full system of four telescopes is expected to be
installed on the definitive site by the end of 2006.
Title: VERITAS: status c.2005
Authors: Weekes, T. C.; Atkins, R. W.; Badran, H. M.; Blaylock, G.;
Bond, I. H.; Boyle, P. J.; Bradbury, S. M.; Buckley, J. H.; Bryum,
K. L.; Carter-Lewis, D. A.; Celik, O.; Chow, Y. C. K.; Cogan, P.; Cui,
W.; Daniel, M. K.; de La Calle Perez, I.; Dowdall, C.; Dowkontt, P.;
Duke, C.; Ergin, T.; Falcone, A. D.; Fegan, D. J.; Fegan, S. J.;
Finley, J. P.; Fortin, P.; Fortson, L.; Gammell, S.; Gibbs, K.;
Gillanders, G. H.; Grube, J.; Guitterez, K. J.; Hall, J.; Hall,
T. A.; Hanna, D.; Hays, E.; Hillas, A. M.; Holder, J.; Horan, D.;
Hughes, S. B.; Humensky, T. B.; Kaaret, P.; Kenny, G. E.; Kertzmann,
M.; Kiedai, D.; Kildea, J.; Knapp, J.; Kosack, K.; Krawczynski, H.;
Krennrich, F.; Lang, M. J.; Lebohec, S.; Linton, E.; Lloyd-Evans, J.;
Maier, G.; Manseri, H.; Milovanovic, A.; Moriarty, P.; Mukherjee,
R.; Nagai, T. N.; Ogden, P. A.; Olevitch, M.; Ong, R. A.; Perkins,
J. S.; Petry, D.; Pizlo, F.; Pohl, M.; Power-Mooney, B.; Quinn, J.;
Quinn, M.; Ragan, K.; Reynolds, P. T.; Rebillot, P.; Rose, H. J.;
Schroedter, M.; Sembroski, G. H.; Steele, D.; Swordy, S. P.; Syson,
A.; Toner, J.; Valcarcel, L.; Vassiliev, V. V.; Wagner, R. G.; Wakely,
S. P.; Walker, G.; White, R. J.; Williams, D. A.; VERITAS Collaboration
Bibcode: 2006AIPC..842.1001W
Altcode:
VERITAS (Very Energetic Radiation Imaging Telescope Array System),
is one of a new generation of TeV gamma-ray observatories. The current
status of its construction is described here. The first two telescopes
and cameras have been completed and meet the design specifications; the
full array of four telescopes could be operational by the end of 2006.
Title: The first VERITAS telescope
Authors: Holder, J.; Atkins, R. W.; Badran, H. M.; Blaylock, G.;
Bradbury, S. M.; Buckley, J. H.; Byrum, K. L.; Carter-Lewis, D. A.;
Celik, O.; Chow, Y. C. K.; Cogan, P.; Cui, W.; Daniel, M. K.; de
la Calle Perez, I.; Dowdall, C.; Dowkontt, P.; Duke, C.; Falcone,
A. D.; Fegan, S. J.; Finley, J. P.; Fortin, P.; Fortson, L. F.;
Gibbs, K.; Gillanders, G.; Glidewell, O. J.; Grube, J.; Gutierrez,
K. J.; Gyuk, G.; Hall, J.; Hanna, D.; Hays, E.; Horan, D.; Hughes,
S. B.; Humensky, T. B.; Imran, A.; Jung, I.; Kaaret, P.; Kenny,
G. E.; Kieda, D.; Kildea, J.; Knapp, J.; Krawczynski, H.; Krennrich,
F.; Lang, M. J.; LeBohec, S.; Linton, E.; Little, E. K.; Maier, G.;
Manseri, H.; Milovanovic, A.; Moriarty, P.; Mukherjee, R.; Ogden,
P. A.; Ong, R. A.; Petry, D.; Perkins, J. S.; Pizlo, F.; Pohl, M.;
Quinn, J.; Ragan, K.; Reynolds, P. T.; Roache, E. T.; Rose, H. J.;
Schroedter, M.; Sembroski, G. H.; Sleege, G.; Steele, D.; Swordy,
S. P.; Syson, A.; Toner, J. A.; Valcarcel, L.; Vassiliev, V. V.;
Wakely, S. P.; Weekes, T. C.; White, R. J.; Williams, D. A.; Wagner, R.
Bibcode: 2006APh....25..391H
Altcode: 2006astro.ph..4119H
The first atmospheric Cherenkov telescope of VERITAS (the Very Energetic
Radiation Imaging Telescope Array System) has been in operation
since February 2005. We present here a technical description of the
instrument and a summary of its performance. The calibration methods
are described, along with the results of Monte Carlo simulations of
the telescope and comparisons between real and simulated data. The
analysis of TeV γ-ray observations of the Crab Nebula, including the
reconstructed energy spectrum, is shown to give results consistent
with earlier measurements. The telescope is operating as expected and
has met or exceeded all design specifications.
Title: TeV Gamma-Ray Observations of the Perseus and Abell 2029
Galaxy Clusters
Authors: Perkins, J. S.; Badran, H. M.; Blaylock, G.; Bradbury, S. M.;
Cogan, P.; Chow, Y. C. K.; Cui, W.; Daniel, M. K.; Falcone, A. D.;
Fegan, S. J.; Finley, J. P.; Fortin, P.; Fortson, L. F.; Gillanders,
G. H.; Gutierrez, K. J.; Grube, J.; Hall, J.; Hanna, D.; Holder, J.;
Horan, D.; Hughes, S. B.; Humensky, T. B.; Kenny, G. E.; Kertzman, M.;
Kieda, D. B.; Kildea, J.; Kosack, K.; Krawczynski, H.; Krennrich, F.;
Lang, M. J.; LeBohec, S.; Maier, G.; Moriarty, P.; Ong, R. A.; Pohl,
M.; Ragan, K.; Rebillot, P. F.; Sembroski, G. H.; Steele, D.; Swordy,
S. P.; Valcarcel, L.; Vassiliev, V. V.; Wakely, S. P.; Weekes, T. C.;
Williams, D. A.; VERITAS Collaboration
Bibcode: 2006ApJ...644..148P
Altcode: 2006astro.ph..2258P
Galaxy clusters might be sources of TeV gamma rays emitted by
high-energy protons and electrons accelerated by large-scale
structure formation shocks, galactic winds, or active galactic
nuclei. Furthermore, gamma rays may be produced in dark matter particle
annihilation processes at the cluster cores. We report on observations
of the galaxy clusters Perseus and A2029 using the 10 m Whipple Cerenkov
telescope during the 2003-2004 and 2004-2005 observing seasons. We
apply a two-dimensional analysis technique to scrutinize the clusters
for TeV emission. In this paper we first determine flux upper limits on
TeV gamma-ray emission from point sources within the clusters. Second,
we derive upper limits on the extended cluster emission. We subsequently
compare the flux upper limits with EGRET upper limits at 100 MeV and
theoretical models. Assuming that the gamma-ray surface brightness
profile mimics that of the thermal X-ray emission and that the spectrum
of cluster cosmic rays extends all the way from thermal energies to
multi-TeV energies with a differential spectral index of -2.1, our
results imply that the cosmic-ray proton energy density is less than
7.9% of the thermal energy density for the Perseus Cluster.
Title: Science Autonomy on a Titan Airborne Platform
Authors: Lorenz, R. D.; Zimmerman, W.; Lunine, J. I.; Reh, K.; Elliott,
J.; Spilker, T.; Hall, J.; Jones, J.; Team, T.
Bibcode: 2006AGUSMIN43E..07L
Altcode:
A prominent concept for future Titan exploration is an airship or
altitude-controlled balloon which could drift or be driven slowly
across Titan's varied, Earth-like landscape. Science goals that such a
mission could address include high- resolution imaging for geomorphology
and meteorology, subsurface sounding by radar, and in-situ sampling
of surface material for analysis of organic composition. On-board
science autonomy has an important role to play in such a mission. One
factor is the 1.25hr one-way light time which drives latency in
ground control intervention during critical events like surface
sampling. A second issue is that while formidable data returns are
possible via a robust combination of direct to earth (DTE - a few
kbps, possibly continuously) and orbiter relay (intermittent windows
of some tens of minutes permitting Gbits per day), the instruments on
the platform are able to generate far larger data volumes. On-board
autonomy will therefore add science value by generating more compact
data products and prioritizing data for downlink. Autonomous science
product generation might include selective highlighting of in-situ
sampling data, generation of mosaic maps, digital elevation models and
trajectory reconstruction from image data (rather than telemetering all
individual images), landscape classification (dunes, river networks,
etc.), and two-dimensional subsurface profiles generated by stacking
individual sounder echoes. This presentation will summarize present
thinking on a future Titan airborne mission and the role of autonomy.
Title: A new search for primordial black hole evaporations using
the Whipple gamma-ray telescope
Authors: Linton, E. T.; Atkins, R. W.; Badran, H. M.; Blaylock, G.;
Boyle, P. J.; Buckley, J. H.; Byrum, K. L.; Carter-Lewis, D. A.;
Celik, O.; Chow, Y. C. K.; Cogan, P.; Daniel, M. K.; Dowdall, C.;
Falcone, A. D.; Fegan, D. J.; Fegan, S. J.; Finley, J. P.; Fortin, P.;
Guiterrez, K. J.; Hall, J.; Hanna, D.; Holder, J.; Horan, D.; Hughes,
S. B.; Humensky, T. B.; Jung, I.; Kenny, G. E.; Kertzman, M.; Kieda,
D. B.; Kildea, J.; Knapp, J.; Krawczynski, H.; Lang, M. J.; LeBohec,
S.; Maier, G.; Moriarty, P.; Ong, R. A.; Perkins, J. S.; Pizlo, F.;
Pohl, M.; Quinn, J.; Ragan, K.; Rebillot, P. F.; Reynolds, P. T.;
Sembroski, G. H.; Steele, D.; Swordy, S. P.; Valcarcel, L.; Wakely,
S. P.; Weekes, T. C.; White, R. J.
Bibcode: 2006JCAP...01..013L
Altcode:
Stephen Hawking's prediction that black holes should radiate like black
bodies has several important consequences, including the possibility of
the detection of small (~1015 g) black holes created in the
very early universe. The detection of such primordial black holes (PBHs)
would be an important discovery, not only confirming Hawking's theory,
but also providing valuable insights into the history of the early
universe. A search through 5.5 years of archival data from the Whipple
Atmospheric Cerenkov Telescope is made for TeV gamma-ray bursts on 1,
3, and 5 s timescales. On the basis of a null result from this direct
search for PBH evaporations, an upper limit of 1.08 × 106
pc-3 yr-1 (99% CL) is set on the PBH evaporation
rate in the local region of the galaxy, assuming the Standard Model of
particle physics. This is more than a factor of two better than the
previous limit at this energy range and includes longer timescales
than have previously been explored. Comparison of this result with
previous limits on the fraction of the critical density comprised by
PBHs, Ωpbh, depends strongly on assumptions made about PBH
clustering; in models predicting strong PBH clustering, the limit in
this work could be as many as ten orders of magnitude more stringently
than those set by diffuse MeV gamma-ray observations.
Title: Experimental results for Titan aerobot thermo-mechanical
subsystem development
Authors: Hall, J.; Jones, J.; Kerzhanovich, V.; Lachenmeier, T.; Mahr,
P.; Pauken, M.; Plett, G.; Smith, L.; van Luvender, M.; Yavrouian, A.
Bibcode: 2006cosp...36..280H
Altcode: 2006cosp.meet..280H
This paper describes experimental results from a development program
focused in maturing Titan aerobot technology in the areas of mechanical
and thermal subsystems Results from four key activities are described
first a cryogenic balloon materials development program involving coupon
and cylinder tests and culminating in the fabrication and subsequent
testing of an inflated 4 6 m long prototype blimp at 93 K second
a combined lab experiment and numerical simulation effort to assess
potential problems resulting from radioisotope thermal generator waste
heat generation near an inflated blimp third an aerial deployment and
inflation development program consisting of laboratory and helicopter
drop tests on a near full scale 11 m long prototype blimp and fourth
a proof of concept experiment demonstrating the viability of using a
mechanically steerable high gain antenna on a floating blimp to perform
direct to Earth telecommunications from Titan The paper provides details
on all of these successful activities and discusses their impact on
the overall effort to produce mature systems technology for future
Titan aerobot missions
Title: Prototype design and testing of a Venus long duration, high
altitude balloon
Authors: Hall, J.; Fairbrother, D.; Frederickson, T.; Kerzhanovich,
V.; Said, M.; Sandy, C.; Willey, C.; Yavrouian, A.
Bibcode: 2006cosp...36..281H
Altcode: 2006cosp.meet..281H
This paper describes the design fabrication and testing of a full
scale prototype balloon intended for long duration flight in the
upper atmosphere of Venus The balloon is 5 5 meters in diameter and is
designed to carry a 45 kg payload at an altitude of 55 km The balloon
material is a 180 g m 2 multi-component laminate comprised of the
following layers bonded together from outside to inside aluminized
Teflon film aluminized Mylar film Vectran fabric and a polyurethane
coating This construction provides the required balloon functional
characteristics of low gas permeability sulfuric acid resistance
and high strength for superpressure operation The design burst
superpressure is 35 000 Pa which is predicted to be twice the worst
case value expected during flight at the highest solar irradiance in
the mission profile The prototype is constructed from 16 gores with
bi-taped seams employing a sulfuric acid resistant adhesive on the
outside Material coupon tests were performed to evaluate the optical
and mechanical characteristics of the laminate These were followed by
full prototype tests for inflation leakage and sulfuric acid tolerance
The results confirmed the suitability of this balloon design for use
at Venus in a long duration mission The various data are presented
and the implications for mission design and operation are discussed
Title: Electron energy spectra, fluxes, and day-night asymmetries of
8B solar neutrinos from measurements with NaCl dissolved
in the heavy-water detector at the Sudbury Neutrino Observatory
Authors: Aharmim, B.; Ahmed, S. N.; Anthony, A. E.; Beier, E. W.;
Bellerive, A.; Bergevin, M.; Biller, S. D.; Boger, J.; Boulay, M. G.;
Bowler, M. G.; Bullard, T. V.; Chan, Y. D.; Chen, M.; Chen, X.;
Cleveland, B. T.; Cox, G. A.; Currat, C. A.; Dai, X.; Dalnoki-Veress,
F.; Deng, H.; Doe, P. J.; Dosanjh, R. S.; Doucas, G.; Duba, C. A.;
Duncan, F. A.; Dunford, M.; Dunmore, J. A.; Earle, E. D.; Elliott,
S. R.; Evans, H. C.; Ewan, G. T.; Farine, J.; Fergani, H.; Fleurot,
F.; Formaggio, J. A.; Frame, K.; Frati, W.; Fulsom, B. G.; Gagnon,
N.; Graham, K.; Grant, D. R.; Hahn, R. L.; Hall, J. C.; Hallin, A. L.;
Hallman, E. D.; Handler, W. B.; Hargrove, C. K.; Harvey, P. J.; Hazama,
R.; Heeger, K. M.; Heelan, L.; Heintzelman, W. J.; Heise, J.; Helmer,
R. L.; Hemingway, R. J.; Hime, A.; Howard, C.; Howe, M. A.; Huang, M.;
Jagam, P.; Jelley, N. A.; Klein, J. R.; Kormos, L. L.; Kos, M. S.;
Krüger, A.; Kraus, C.; Krauss, C. B.; Krumins, A. V.; Kutter, T.;
Kyba, C. C.; Labranche, H.; Lange, R.; Law, J.; Lawson, I. T.; Lesko,
K. T.; Leslie, J. R.; Levine, I.; Loach, J. C.; Luoma, S.; MacLellan,
R.; Majerus, S.; Mak, H. B.; Maneira, J.; Marino, A. D.; McCauley,
N.; McDonald, A. B.; McGee, S.; McGregor, G.; Mifflin, C.; Miknaitis,
K. K.; Moffat, B. A.; Nally, C. W.; Neubauer, M. S.; Nickel, B. G.;
Noble, A. J.; Norman, E. B.; Oblath, N. S.; Okada, C. E.; Ollerhead,
R. W.; Orrell, J. L.; Oser, S. M.; Ouellet, C.; Peeters, S. J.; Poon,
A. W.; Rielage, K.; Robertson, B. C.; Robertson, R. G.; Rollin, E.;
Rosendahl, S. S.; Rusu, V. L.; Schwendener, M. H.; Seibert, S. R.;
Simard, O.; Simpson, J. J.; Sims, C. J.; Sinclair, D.; Skensved,
P.; Smith, M. W.; Starinsky, N.; Stokstad, R. G.; Stonehill, L. C.;
Tafirout, R.; Takeuchi, Y.; Tešić, G.; Thomson, M.; Thorman, M.;
Tsui, T.; van Berg, R.; Water, R. G.; Virtue, C. J.; Wall, B. L.;
Waller, D.; Waltham, C. E.; Tseung, H. Wan; Wark, D. L.; Wendland,
J.; West, N.; Wilkerson, J. F.; Wilson, J. R.; Wittich, P.; Wouters,
J. M.; Wright, A.; Yeh, M.; Zuber, K.
Bibcode: 2005PhRvC..72e5502A
Altcode: 2005nucl.ex...2021S
Results are reported from the complete salt phase of the Sudbury
Neutrino Observatory experiment in which NaCl was dissolved in the
2H2O (“D2O”) target. The addition
of salt enhanced the signal from neutron capture as compared to the
pure D2O detector. By making a statistical separation
of charged-current events from other types based on event-isotropy
criteria, the effective electron recoil energy spectrum has been
extracted. In units of 106cm-2s-1,
the total flux of active-flavor neutrinos
from 8B decay in the Sun is found to be
4.94+0.21-0.21(stat)+0.38-0.34(syst)
and the integral flux of electron neutrinos
for an undistorted 8B spectrum is
1.68+0.06-0.06(stat)+0.08-0.09(syst);
the signal from (νx,e) elastic
scattering is equivalent to an electron-neutrino flux of
2.35+0.22-0.22(stat)+0.15-0.15(syst).
These results are consistent with those expected for neutrino
oscillations with the so-called large mixing angle parameters and
also with an undistorted spectrum. A search for matter-enhancement
effects in the Earth through a possible day-night asymmetry
in the charged-current integral rate is consistent with
no asymmetry. Including results from other experiments,
the best-fit values for two-neutrino mixing parameters are
Δm2=(8.0+0.6-0.4)×10-5
eV2 and θ=33.9+2.4-2.2 degrees.
Title: A Multiwavelength View of the TeV Blazar Markarian 421:
Correlated Variability, Flaring, and Spectral Evolution
Authors: Błażejowski, M.; Blaylock, G.; Bond, I. H.; Bradbury,
S. M.; Buckley, J. H.; Carter-Lewis, D. A.; Celik, O.; Cogan, P.; Cui,
W.; Daniel, M.; Duke, C.; Falcone, A.; Fegan, D. J.; Fegan, S. J.;
Finley, J. P.; Fortson, L.; Gammell, S.; Gibbs, K.; Gillanders, G. G.;
Grube, J.; Gutierrez, K.; Hall, J.; Hanna, D.; Holder, J.; Horan, D.;
Humensky, B.; Kenny, G.; Kertzman, M.; Kieda, D.; Kildea, J.; Knapp,
J.; Kosack, K.; Krawczynski, H.; Krennrich, F.; Lang, M.; LeBohec,
S.; Linton, E.; Lloyd-Evans, J.; Maier, G.; Mendoza, D.; Milovanovic,
A.; Moriarty, P.; Nagai, T. N.; Ong, R. A.; Power-Mooney, B.; Quinn,
J.; Quinn, M.; Ragan, K.; Reynolds, P. T.; Rebillot, P.; Rose,
H. J.; Schroedter, M.; Sembroski, G. H.; Swordy, S. P.; Syson, A.;
Valcarel, L.; Vassiliev, V. V.; Wakely, S. P.; Walker, G.; Weekes,
T. C.; White, R.; Zweerink, J.; VERITAS Collaboration; Mochejska,
B.; Smith, B.; Aller, M.; Aller, H.; Teräsranta, H.; Boltwood, P.;
Sadun, A.; Stanek, K.; Adams, E.; Foster, J.; Hartman, J.; Lai, K.;
Böttcher, M.; Reimer, A.; Jung, I.
Bibcode: 2005ApJ...630..130B
Altcode: 2005astro.ph..5325B
We report results from an intensive multiwavelength monitoring
campaign on the TeV blazar Mrk 421 over the period of 2003-2004. The
source was observed simultaneously at TeV energies with the Whipple
10 m telescope and at X-ray energies with the Rossi X-Ray Timing
Explorer (RXTE) during each clear night within the Whipple observing
windows. Supporting observations were also frequently carried
out at optical and radio wavelengths to provide simultaneous or
contemporaneous coverages. The large amount of simultaneous data
has allowed us to examine the variability of Mrk 421 in detail,
including cross-band correlation and broadband spectral variability,
over a wide range of flux. The variabilities are generally correlated
between the X-ray and gamma-ray bands, although the correlation appears
to be fairly loose. The light curves show the presence of flares with
varying amplitudes on a wide range of timescales at both X-ray and TeV
energies. Of particular interest is the presence of TeV flares that
have no coincident counterparts at longer wavelengths, because the
phenomenon seems difficult to understand in the context of the proposed
emission models for TeV blazars. We have also found that the TeV flux
reached its peak days before the X-ray flux did during a giant flare
(or outburst) in 2004 (with the peak flux reaching ~135 mcrab in X-rays,
as seen by the RXTE ASM, and ~3 crab in gamma rays). Such a difference
in the development of the flare presents a further challenge to both
the leptonic and hadronic emission models. Mrk 421 varied much less at
optical and radio wavelengths. Surprisingly, the normalized variability
amplitude in the optical seems to be comparable to that in the radio,
perhaps suggesting the presence of different populations of emitting
electrons in the jet. The spectral energy distribution of Mrk 421 is
seen to vary with flux, with the two characteristic peaks moving toward
higher energies at higher fluxes. We have failed to fit the measured
spectral energy distributions (SEDs) with a one-zone synchrotron
self-Compton model; introducing additional zones greatly improves the
fits. We have derived constraints on the physical properties of the
X-ray/gamma-ray flaring regions from the observed variability (and SED)
of the source. The implications of the results are discussed.
Title: Autonomous Flight Control for a Titan Exploration Aerobot
Authors: Elfes, A.; Montgomery, J.; Hall, J.; Joshi, S.; Hall, J.;
Payne, J.; Bergh, C.
Bibcode: 2005ESASP.603E..91E
Altcode: 2005aira.confE..91E
No abstract at ADS
Title: Development of bubble chambers with sensitivity to WIMPs
Authors: Bond, L.; Collar, J. I.; Ely, J.; Flake, M.; Hall, J.;
Jordan, D.; Nakazawa, D.; Raskin, A.; Sonnenschein, A.; Sullivan, K. O.
Bibcode: 2005NewAR..49..271B
Altcode:
Bubble nucleation in moderately superheated liquids can be triggered by
nuclear recoils from WIMPs. This phenomenon is the basis for superheated
droplet detectors. The droplet technique is currently limited by
insensitivity to spin-independent interactions, due to lack of heavy
elements in the usual target liquids, and sensitivity to contamination
of the gel by alpha emitters. As an alternative, we have developed a new
type of homogeneous bubble chamber, which can contain heavy liquids,
including CF 3Br, CF 3I, and C 3F
8. Detectors of this type may be scalable to large size at
modest cost and could have very low backgrounds. We discuss results
obtained with a 12 ml prototype and plans for a 1 liter chamber.
Title: Indirect Observations of the Dark Matter at TeV Gamma-Ray
Energies
Authors: Hall, J.
Bibcode: 2005AAS...206.2105H
Altcode: 2005BAAS...37..462H
Non-baryonic dark matter (DM) could emit gamma rays if the DM consists
of weakly interacting massive particles (WIMPs). Particle theories
for WIMPs suggest that they could annihilate producing gamma rays
as a final product. The Galactic Center dynamics observed in the IR
seems to be driven by three million solar masses within 90 AU of the
dynamical center of the Milky Way. TeV gamma rays were detected in
the same direction. We discuss the possibility that the TeV radiation
from the GC results from annihilating WIMPs using a neutralino as our
particle model. We use the IR observations to constrain the dark matter
density profile. Other DM dominated systems such as dwarf galaxies
are also promising for indirect detection of the DM. We discuss an
ongoing program to observe DM dominated systems at TeV energies.
Title: A Survey of Unidentified EGRET Sources at Very High Energies
Authors: Fegan, S. J.; Badran, H. M.; Bond, I. H.; Boyle, P. J.;
Bradbury, S. M.; Buckley, J. H.; Carter-Lewis, D. A.; Catanese, M.;
Celik, O.; Cui, W.; Daniel, M.; D'Vali, M.; de la Calle Perez, I.;
Duke, C.; Falcone, A.; Fegan, D. J.; Finley, J. P.; Fortson, L. F.;
Gaidos, J. A.; Gammell, S.; Gibbs, K.; Gillanders, G. H.; Grube, J.;
Hall, J.; Hall, T. A.; Hanna, D.; Hillas, A. M.; Holder, J.; Horan,
D.; Jarvis, A.; Jordan, M.; Kenny, G. E.; Kertzman, M.; Kieda, D.;
Kildea, J.; Knapp, J.; Kosack, K.; Krawczynski, H.; Krennrich, F.;
Lang, M. J.; Le Bohec, S.; Lessard, R. W.; Linton, E.; Lloyd-Evans, J.;
Milovanovic, A.; McEnery, J.; Moriarty, P.; Mukherjee, R.; Muller,
D.; Nagai, T.; Nolan, S.; Ong, R. A.; Pallassini, R.; Petry, D.;
Power-Mooney, B.; Quinn, J.; Quinn, M.; Ragan, K.; Rebillot, P.;
Reynolds, P. T.; Rose, H. J.; Schroedter, M.; Sembroski, G. H.;
Swordy, S. P.; Syson, A.; Vassiliev, V. V.; Wakely, S. P.; Walker,
G.; Weekes, T. C.; Zweerink, J.
Bibcode: 2005ApJ...624..638F
Altcode:
The Whipple Observatory 10 m γ-ray telescope has been used to survey
the error boxes of EGRET unidentified sources in an attempt to find
counterparts at energies of 350 GeV and above. Twenty-one unidentified
sources detected by EGRET (more than 10% of the total number) have
been included in this survey. In no case is a statistically significant
signal found in the EGRET error box, which implies that, at least for
this sample, the γ-ray spectra of these sources steepen between 100
MeV and 350 GeV. For each EGRET source location, we list candidate
associations and derive upper limits on the integral γ-ray flux above
350 GeV.
Title: Spectrum of Very High Energy Gamma-Rays from the blazar 1ES
1959+650 during Flaring Activity in 2002
Authors: Daniel, M. K.; Badran, H. M.; Bond, I. H.; Boyle, P. J.;
Bradbury, S. M.; Buckley, J. H.; Carter-Lewis, D. A.; Catanese, M.;
Celik, O.; Cogan, P.; Cui, W.; D'Vali, M.; de la Calle Perez, I.; Duke,
C.; Falcone, A.; Fegan, D. J.; Fegan, S. J.; Finley, J. P.; Fortson,
L. F.; Gaidos, J. A.; Gammell, S.; Gibbs, K.; Gillanders, G. H.; Grube,
J.; Hall, J.; Hall, T. A.; Hanna, D.; Hillas, A. M.; Holder, J.; Horan,
D.; Humensky, T. B.; Jarvis, A.; Jordan, M.; Kenny, G. E.; Kertzman,
M.; Kieda, D.; Kildea, J.; Knapp, J.; Kosack, K.; Krawczynski, H.;
Krennrich, F.; Lang, M. J.; Le Bohec, S.; Linton, E.; Lloyd-Evans,
J.; Milovanovic, A.; Moriarty, P.; Müller, D.; Nagai, T.; Nolan,
S.; Ong, R. A.; Pallassini, R.; Petry, D.; Power-Mooney, B.; Quinn,
J.; Quinn, M.; Ragan, K.; Rebillot, P.; Reynolds, P. T.; Rose, H. J.;
Schroedter, M.; Sembroski, G. H.; Swordy, S. P.; Syson, A.; Vassiliev,
V. V.; Wakely, S. P.; Walker, G.; Weekes, T. C.; Zweerink, J.
Bibcode: 2005ApJ...621..181D
Altcode: 2005astro.ph..3085D
The blazar 1ES 1959+650 was observed in a flaring state with the Whipple
10 m Imaging Atmospheric Cerenkov Telescope in 2002 May. A spectral
analysis has been carried out on the data from that time period,
and the resulting very high energy gamma-ray spectrum (E>=316
GeV) can be well fitted by a power law of differential spectral index
α=2.78+/-0.12stat+/-0.21sys. On 2002 June 4, the
source flared dramatically in the gamma-ray range without any coincident
increase in the X-ray emission, providing the first unambiguous
example of an ``orphan'' gamma-ray flare from a blazar. The gamma-ray
spectrum for these data can also be described by a simple power-law
fit with α=2.82+/-0.15stat+/-0.30sys. There is
no compelling evidence for spectral variability or for any cutoff to
the spectrum.
Title: The very high energy gamma ray spectra of IES 1959+650 and
Mrk 421 as measured with the Whipple 10 m telescope
Authors: Daniel, M. K.; Badran, H. M.; Bond, I. H.; Boyle, P. J.;
Bradbury, S. M.; Buckley, J. H.; Byrum, K.; Carter-Lewis, D. A.; Celik,
O.; Cogan, P.; Cui, W.; de La Calle Perez, I.; Duke, C.; Falcone,
A.; Fegan, D. J.; Fegan, S. J.; Finley, J. P.; Fortson, L. F.;
Gammell, S.; Gibbs, K.; Gillanders, G. H.; Grube, J.; Guiterrez,
K. J.; Hall, J.; Hanna, D.; Holder, J.; Horan, D.; Hughes, S.;
Humensky, T. B.; Jung, I.; Kenny, G. E.; Kertzman, M.; Kieda, D.;
Kildea, J.; Knapp, J.; Kosack, K.; Krawczynski, H.; Krennrich, F.;
Lang, M. J.; Le Bohec, S.; Linton, E.; Lloyd-Evans, J.; Mendoza, D.;
Merriman, A.; Milovanovic, A.; Moriarty, P.; Nagai, T.; Ong, R. A.;
Pallassini, R.; Perkins, J.; Petry, D.; Pohl, M.; Power-Mooney, B.;
Quinn, J.; Quinn, M.; Ragan, K.; Rebillot, P.; Reynolds, P. T.; Rose,
H. J.; Schroedter, M.; Sembroski, G. H.; Swordy, S. P.; Syson, A.;
Valcarcel, L.; Vassiliev, V. V.; Wagner, R.; Wakely, S. P.; Walker,
G.; Weekes, T. C.; White, R. J.; Zweerink, J.; VERITAS Collaboration
Bibcode: 2005AIPC..745..462D
Altcode:
No abstract at ADS
Title: Recent Observations of IC443 with the Whipple 10m Telescope
Authors: VERITAS Collaboration; Badran, H. M.; Blaylock, G.; Bond,
I. H.; Boyle, P. J.; Bradbury, S. M.; Buckley, J. H.; Byrum, K.;
Carter-Lewis, D. A.; Celik, O.; Cogan, P.; Cui, W.; de La Calle Perez,
I.; Daniel, M. K.; Duke, C.; Falcone, A.; Fegan, D. J.; Fegan, S. J.;
Finley, J. P.; Fortson, L. F.; Gammell, S.; Gibbs, K.; Gillanders,
G. H.; Grube, J.; Guiterrez, K. J.; Hall, J.; Hanna, D.; Horan,
D.; Hughes, S.; Humensky, T. B.; Jung, I.; Kenny, G. E.; Kertzman,
M.; Kieda, D.; Kildea, J.; Knapp, J.; Kosack, K.; Krawczynski, H.;
Krennrich, F.; Lang, M. J.; Le Bohec, S.; Linton, E.; Lloyd-Evans,
J.; Mendoza, D.; Merriman, A.; Milovanovic, A.; Moriarty, P.; Nagai,
T.; Ong, R. A.; Pallassini, R.; Perkins, J.; Petry, D.; Pohl, M.;
Power-Mooney, B.; Quinn, J.; Quinn, M.; Ragan, K.; Rebillot, P.;
Reynolds, P. T.; Rose, H. J.; Schroedter, M.; Sembroski, G. H.; Swordy,
S. P.; Syson, A.; Valcarcel, L.; Vassiliev, V. V.; Wagner, R.; Wakely,
S. P.; Walker, G.; Weekes, T. C.; White, R. J.; Zweerink, J.
Bibcode: 2005AIPC..745..275V
Altcode:
We present here the results of recent observations made with the Whipple
10m imaging Cherenkov telescope of the region of the supernova remnant
IC443. No evidence for gamma-ray emission was found, and we obtain an
upper limit above 500 GeV (99.9% confidence) of 0.6 × 10-7
ph m-2 s-1 (0.11 Crab) at the location of the
recently identified X-ray plerion nebula and 0.8 × 10-7
ph m-2 s-1 (0.14 Crab) at the site of the OH
maser at the densest part of the molecular cloud.
Title: Very High Energy Observations of Gamma Ray Bursts with the
Whipple/VERITAS Telescopes
Authors: Horan, D.; Badran, H. M.; Blaylock, G.; Bond, I. H.; Boyle,
P. J.; Bradbury, S. M.; Buckley, J. H.; Byrum, K.; Carter-Lewis, D. A.;
Celik, O.; Cogan, P.; Cui, W.; Daniel, M. K.; de La Calle Perez, I.;
Duke, C.; Falcone, A.; Fegan, D. J.; Fegan, S. J.; Finley, J. P.;
Fortson, L. F.; Gammell, S.; Gibbs, K.; Gillanders, G. H.; Grube,
J.; Guiterrez, K. J.; Hall, J.; Hanna, D.; Holder, J.; Hughes, S.;
Humensky, T. B.; Jung, I.; Kenny, G. E.; Kertzman, M.; Kieda, D.;
Kildea, J.; Knapp, J.; Kosack, K.; Krawczynski, H.; Krennrich, F.;
Lang, M. J.; Le Bohec, S.; Linton, E.; Lloyd-Evans, J.; Mendoza, D.;
Merriman, A.; Milovanovic, A.; Moriarty, P.; Nagai, T.; Ong, R. A.;
Pallassini, R.; Perkins, J.; Petry, D.; Pohl, M.; Power-Mooney, B.;
Quinn, J.; Quinn, M.; Ragan, K.; Rebillot, P.; Reynolds, P. T.; Rose,
H. J.; Schroedter, M.; Sembroski, G. H.; Swordy, S. P.; Syson, A.;
Valcarcel, L.; Vassiliev, V. V.; Wagner, R.; Wakely, S. P.; Walker,
G.; Weekes, T. C.; White, R. J.; Zweerink, J.
Bibcode: 2005AIPC..745..591H
Altcode:
Gamma-ray Burst (GRB) observations at Very High Energies (VHE,
E > 100 GeV) can impose tight constraints on some GRB emission
models. Many GRB after-glow models predict a VHE component similar to
that seen in blazars and supernova remnants, in which the GRB spectral
energy distribution has a double-peaked shape extending into the VHE
regime. Consistent with this afterglow scenario, EGRET detected delayed
high energy emission from all five bright BATSE GRBs that occurred
within its field of view. GRB observations have had high priority in
the observing program at the Whipple 10m Telescope and will continue to
be high priority targets when the next generation observatory VERITAS
comes online. Upper limits on the VHE emission from ten GRBs observed
with the Whipple Telescope are reported here.
Title: The VERITAS Prototype and the Upcoming VERITAS Array
Authors: Falcone, Abe D.; Badran, H. M.; Blaylock, G.; Bond, I. H.;
Boyle, P. J.; Bradbury, S. M.; Buckley, J. H.; Byrum, K.; Carter-Lewis,
D. A.; Celik, O.; Cogan, P.; Cui, W.; Daniel, M.; de La Calle Perez,
I.; Dowkontt, P.; Duke, C.; Fegan, D. J.; Fegan, S. J.; Finley, J. P.;
Fortson, L. F.; Gammell, S.; Gibbs, K.; Gillanders, G. H.; Grube, J.;
Guiterrez, K. J.; Hall, J.; Hanna, D.; Holder, J.; Horan, D.; Hughes,
S.; Humensky, T. B.; Jung, I.; Kenny, G. E.; Kertzman, M.; Kieda,
D.; Kildea, J.; Knapp, J.; Kosack, K.; Krawczynski, H.; Krennrich,
F.; Lang, M. J.; Le Bohec, S.; Linton, E.; Lloyd-Evans, J.; Mendoza,
D.; Merriman, A.; Milovanovic, A.; Moriarty, P.; Nagai, T.; Olevitch,
M.; Ong, R. A.; Pallassini, R.; Perkins, J.; Petry, D.; Pizlo, F.;
Pohl, M.; Power-Mooney, B.; Quinn, J.; Quinn, M.; Ragan, K.; Rebillot,
P.; Reynolds, P. T.; Rose, H. J.; Schroedter, M.; Sembroski, G. H.;
Swordy, S. P.; Syson, A.; Valcarcel, L.; Vassiliev, V. V.; Wagner,
R.; Wakely, S. P.; Walker, G.; Weekes, T. C.; White, R. J.; Zweerink,
J.; VERITAS Collaboration
Bibcode: 2005AIPC..745..633F
Altcode:
No abstract at ADS
Title: Recent Observations of IC443 with the Whipple 10m Telescope
Authors: Holder, J.; Badran, H. M.; Blaylock, G.; Bond, I. H.; Boyle,
P. J.; Bradbury, S. M.; Buckley, J. H.; Byrum, K.; Carter-Lewis, D. A.;
Celik, O.; Cogan, P.; Cui, W.; de La Calle Perez, I.; Daniel, M. K.;
Duke, C.; Falcone, A.; Fegan, D. J.; Fegan, S. J.; Finley, J. P.;
Fortson, L. F.; Gammell, S.; Gibbs, K.; Gillanders, G. H.; Grube,
J.; Guiterrez, K. J.; Hall, J.; Hanna, D.; Horan, D.; Hughes, S.;
Humensky, T. B.; Jung, I.; Kenny, G. E.; Kertzman, M.; Kieda, D.;
Kildea, J.; Knapp, J.; Kosack, K.; Krawczynski, H.; Krennrich, F.;
Lang, M. J.; Le Bohec, S.; Linton, E.; Lloyd-Evans, J.; Mendoza, D.;
Merriman, A.; Milovanovic, A.; Moriarty, P.; Nagai, T.; Ong, R. A.;
Pallassini, R.; Perkins, J.; Petry, D.; Pohl, M.; Power-Mooney, B.;
Quinn, J.; Quinn, M.; Ragan, K.; Rebillot, P.; Reynolds, P. T.; Rose,
H. J.; Schroedter, M.; Sembroski, G. H.; Swordy, S. P.; Syson, A.;
Valcarcel, L.; Vassiliev, V. V.; Wagner, R.; Wakely, S. P.; Walker,
G.; Weekes, T. C.; White, R. J.; Zweerink, J.; VERITAS Collaboration
Bibcode: 2005AIPC..745..275H
Altcode:
No abstract at ADS
Title: The VERITAS Prototype and the Upcoming VERITAS Array
Authors: VERITAS Collaboration; Badran, H. M.; Blaylock, G.;
Bond, I. H.; Boyle, P. J.; Bradbury, S. M.; Buckley, J. H.; Byrum,
K.; Carter-Lewis, D. A.; Celik, O.; Cogan, P.; Cui, W.; Daniel,
M.; de La Calle Perez, I.; Dowkontt, P.; Duke, C.; Fegan, D. J.;
Fegan, S. J.; Finley, J. P.; Fortson, L. F.; Gammell, S.; Gibbs, K.;
Gillanders, G. H.; Grube, J.; Guiterrez, K. J.; Hall, J.; Hanna, D.;
Holder, J.; Horan, D.; Hughes, S.; Humensky, T. B.; Jung, I.; Kenny,
G. E.; Kertzman, M.; Kieda, D.; Kildea, J.; Knapp, J.; Kosack, K.;
Krawczynski, H.; Krennrich, F.; Lang, M. J.; Le Bohec, S.; Linton,
E.; Lloyd-Evans, J.; Mendoza, D.; Merriman, A.; Milovanovic, A.;
Moriarty, P.; Nagai, T.; Olevitch, M.; Ong, R. A.; Pallassini, R.;
Perkins, J.; Petry, D.; Pizlo, F.; Pohl, M.; Power-Mooney, B.; Quinn,
J.; Quinn, M.; Ragan, K.; Rebillot, P.; Reynolds, P. T.; Rose, H. J.;
Schroedter, M.; Sembroski, G. H.; Swordy, S. P.; Syson, A.; Valcarcel,
L.; Vassiliev, V. V.; Wagner, R.; Wakely, S. P.; Walker, G.; Weekes,
T. C.; White, R. J.; Zweerink, J.
Bibcode: 2005AIPC..745..633V
Altcode:
The prototype for the VERITAS imaging atmospheric Cherenkov telescope
array was successfully operated in southern Arizona between September
2003 and April 2004. The prototype consisted of 86 mirror facets
mounted centrally on a 12-meter dish, which was built to accommodate
up to 350 facets when converted to a complete VERITAS telescope. The
camera consisted of half of the full 499 pixel camera. The signal and
trigger electronics were nearly identical to those that will be used
for the individual VERITAS array telescopes. By observing the Crab and
Mrk421, as well as performing a variety of tests, the characteristics
of the instrument were evaluated. The prototype met all performance
expectations and served as a valuable test bed for the current design,
as well as for the construction and operation of VERITAS. This prototype
instrument is now being upgraded to a complete VERITAS telescope that
will be operated during the construction of the full VERITAS array. The
array is expected to be operational by November 2006.
Title: The very high energy gamma ray spectra of IES 1959+650 and
Mrk 421 as measured with the Whipple 10 m telescope
Authors: VERITAS Collaboration; Badran, H. M.; Bond, I. H.; Boyle,
P. J.; Bradbury, S. M.; Buckley, J. H.; Byrum, K.; Carter-Lewis,
D. A.; Celik, O.; Cogan, P.; Cui, W.; de La Calle Perez, I.;
Duke, C.; Falcone, A.; Fegan, D. J.; Fegan, S. J.; Finley, J. P.;
Fortson, L. F.; Gammell, S.; Gibbs, K.; Gillanders, G. H.; Grube, J.;
Guiterrez, K. J.; Hall, J.; Hanna, D.; Holder, J.; Horan, D.; Hughes,
S.; Humensky, T. B.; Jung, I.; Kenny, G. E.; Kertzman, M.; Kieda, D.;
Kildea, J.; Knapp, J.; Kosack, K.; Krawczynski, H.; Krennrich, F.;
Lang, M. J.; Le Bohec, S.; Linton, E.; Lloyd-Evans, J.; Mendoza, D.;
Merriman, A.; Milovanovic, A.; Moriarty, P.; Nagai, T.; Ong, R. A.;
Pallassini, R.; Perkins, J.; Petry, D.; Pohl, M.; Power-Mooney, B.;
Quinn, J.; Quinn, M.; Ragan, K.; Rebillot, P.; Reynolds, P. T.; Rose,
H. J.; Schroedter, M.; Sembroski, G. H.; Swordy, S. P.; Syson, A.;
Valcarcel, L.; Vassiliev, V. V.; Wagner, R.; Wakely, S. P.; Walker,
G.; Weekes, T. C.; White, R. J.; Zweerink, J.
Bibcode: 2005AIPC..745..462V
Altcode:
In observations made with the Whipple 10 m telescope, 1ES 1959+650 (z
= 0.048) was caught in a high flaring state in May 2002, concurrent
with a high X-ray state, and in June 2002, for which there was no
corresponding X-ray flare. The spectra for both of those occasions
are well fitted by a power law of differential spectral index ~
-2.8. The relative stability of the spectral index for those flares
argues strongly in favour of a two-component model as to the emission
zones for the two radiation regimes. Markarian 421 (z = 0.031)
was observed to be in a high flaring state, at levels of >= 3 Crab,
during March and April 2004. The average spectrum over this time period
shows evidence for a cut-off in the spectrum at ~ 5 TeV, similar to a
cut-off seen during an equivalently strong episode of flaring activity
in 2001. The continued appearance of this feature indicates a long
term stability, either in the physical conditions at the source, or
in the intervening medium (such as attenuation on the extra-galactic
infra-red background radiation).
Title: Search for TeV Radiation from Selected Local Group Galaxies
Authors: Hall, J.
Bibcode: 2005ICRC....4...69H
Altcode: 2005astro.ph..7448H; 2005ICRC...29d..69H
Some candidate dark matter particles, such as neutralinos in
supersymmetry, would annihilate producing GeV/TeV gamma rays. We
report on recent observations of two dwarf spheroid galaxies, Draco,
Ursa Minor, the compact elliptical galaxy M32, and the spiral galaxy
M33 with the Whipple 10m gamma-ray telescope. No significant signal
was found, and we derived upper limits for the gamma-ray flux from
each object. We discuss our astrophysical selection criteria for these
galaxies in the context of an indirect search for dark matter and the
implications of these flux upper limits on the density of neutralinos.
Title: A Search for TeV Gamma-Ray Emission from High-peaked
Flat-Spectrum Radio Quasars Using the Whipple Air Cerenkov Telescope
Authors: Falcone, A. D.; Bond, I. H.; Boyle, P. J.; Bradbury, S. M.;
Buckley, J. H.; Carter-Lewis, D.; Celik, O.; Cui, W.; Daniel, M.;
D'Vali, M.; de la Calle Perez, I.; Duke, C.; Fegan, D. J.; Fegan,
S. J.; Finley, J. P.; Fortson, L. F.; Gaidos, J.; Gammell, S.;
Gibbs, K.; Gillanders, G. H.; Grube, J.; Hall, J.; Hall, T. A.;
Hanna, D.; Hillas, A. M.; Holder, J.; Horan, D.; Jarvis, A.; Kenny,
G. E.; Kertzman, M.; Kieda, D.; Kildea, J.; Knapp, J.; Kosack, K.;
Krawczynski, H.; Krennrich, F.; Lang, M. J.; LeBohec, S.; Linton,
E.; Lloyd-Evans, J.; Milovanovic, A.; Moriarty, P.; Muller, D.;
Nagai, T.; Nolan, S.; Ong, R.; Pallassini, R.; Petry, D.; Pizlo,
F.; Power-Mooney, B.; Quinn, J.; Quinn, M.; Ragan, K.; Rebillot, P.;
Reynolds, P. T.; Rose, H. J.; Schroedter, M.; Sembroski, G.; Swordy,
S. P.; Syson, A.; Tyler, K.; Vassiliev, V. V.; Wakely, S. P.; Walker,
G.; Weekes, T. C.; Zweerink, J.
Bibcode: 2004ApJ...613..710F
Altcode: 2004astro.ph..8365F
Blazars have traditionally been separated into two broad categories
based on their optical emission characteristics. Blazars with faint
or no emission lines are referred to as BL Lacertae objects (BL Lacs),
and blazars with prominent, broad emission lines are commonly referred
to as flat-spectrum radio quasars (FSRQs). The spectral energy
distribution of FSRQs has generally been thought of as being more
akin to the low-peaked BL Lacs, which exhibit a peak in the infrared
region of the spectrum, as opposed to high-peaked BL Lacs (HBLs),
which exhibit a peak in UV/X-ray region of the spectrum. All blazars
that are currently confirmed as sources of TeV emission fall into the
HBL category. Recent surveys have found several FSRQs that exhibit
spectral properties, particularly the synchrotron peak frequency,
similar to HBLs. These objects are potential sources of TeV emission
according to several models of blazar jet emission and the evolution
of blazars. Measurements of TeV flux or flux upper limits could
impact existing theories explaining the links between different blazar
types and could have a significant impact on our understanding of the
nature of objects that are capable of TeV emission. In particular,
the presence (or absence) of TeV emission from FSRQs could confirm
(or cast doubt on) recent evolutionary models that expect intermediate
objects in a transitional state between FSRQ and BL Lac. The Whipple
10 m imaging air Cerenkov gamma-ray telescope is well suited for TeV
gamma-ray observations. Using the Whipple telescope, we have taken data
on a small selection of nearby (z<0.1 in most cases) high-peaked
FSRQs. Although one of the objects, B2 0321+33, showed marginal evidence
of flaring, no significant emission was detected. The implications of
this paucity of emission and the derived upper limits are discussed.
Title: The Chromospheric Activity and Variability of Cycling and
Flat Activity Solar-Analog Stars
Authors: Hall, Jeffrey C.; Lockwood, G. W.
Bibcode: 2004ApJ...614..942H
Altcode:
We present an analysis of more than 3700 observations of the Ca II H
and K lines in 57 Sun-like stars and over 3000 analogous observations
of the Sun. Ten of the 57 stars under consideration are observed in
flat states, but these stars do not always exhibit overall Ca II H and
K core brightness below that of solar minimum. Solar activity minimum
lies near the lowest level observed for stars with cyclic or irregular
variability, but many flat stars have HK activity levels comparable to
or exceeding that of solar minimum. While flat activity stars may be
in periods of extended activity minima analogous to the solar Maunder
minimum, a significant reduction in magnetic activity during such
periods is not implied (although it is also not rejected) by the data.
Title: Observation of M87 at 400 GeV with the Whipple 10 Meter
Telescope
Authors: Le Bohec, S.; Badran, H. M.; Bond, I. H.; Boyle, P. J.;
Bradbury, S. M.; Buckley, J. H.; Carter-Lewis, D. A.; Catanese, M.;
Celik, O.; Cui, W.; Daniel, M.; D'Vali, M.; de la Calle Perez, I.;
Duke, C.; Falcone, A.; Fegan, D. J.; Fegan, S. J.; Finley, J. P.;
Fortson, L. F.; Gaidos, J. A.; Gammell, S.; Gibbs, K.; Gillanders,
G. H.; Grube, J.; Hall, J.; Hall, T. A.; Hanna, D.; Hillas, A. M.;
Holder, J.; Horan, D.; Jarvis, A.; Jordan, M.; Kenny, G. E.; Kertzman,
M.; Kieda, D.; Kildea, J.; Knapp, J.; Kosack, K.; Krawczynski, H.;
Krennrich, F.; Lang, M. J.; Linton, E.; Lloyd-Evans, J.; Milovanovic,
A.; Moriarty, P.; Müller, D.; Nagai, T.; Nolan, S.; Ong, R. A.;
Pallassini, R.; Petry, D.; Power-Mooney, B.; Quinn, J.; Quinn, M.;
Ragan, K.; Rebillot, P.; Reynolds, P. T.; Rose, H. J.; Schroedter,
M.; Sembroski, G. H.; Swordy, S. P.; Syson, A.; Vassiliev, V. V.;
Wakely, S. P.; Walker, G.; Weekes, T. C.; Zweerink, J.
Bibcode: 2004ApJ...610..156L
Altcode:
We present results from observations taken with the Whipple 10 m
very high energy γ-ray telescope with maximal sensitivity at 400 GeV
during 39 hr between 2000 and 2003 in the direction of the giant radio
galaxy M87. Using the entire data set, we derive a 99% confidence level
upper limit on the flux of γ-ray emission above 400 GeV from M87 to
be <=6.9×10-12 cm-2 s-1. This
suggests variability at the 90% confidence level when compared to the
flux measured by the HEGRA collaboration in 1999 if the differential
spectrum is steeper than a power law of index 3.75. Our search for a
correlation between the Rossi X-Ray Timing Explorer all-sky monitor
observation and a potential γ-ray signal is inconclusive.
Title: TeV Gamma-Ray Observations of the Galactic Center
Authors: Kosack, K.; Badran, H. M.; Bond, I. H.; Boyle, P. J.;
Bradbury, S. M.; Buckley, J. H.; Carter-Lewis, D. A.; Celik, O.;
Connaughton, V.; Cui, W.; Daniel, M.; D'Vali, M.; de la Calle Perez,
I.; Duke, C.; Falcone, A.; Fegan, D. J.; Fegan, S. J.; Finley, J. P.;
Fortson, L. F.; Gaidos, J. A.; Gammell, S.; Gibbs, K.; Gillanders,
G. H.; Grube, J.; Gutierrez, K.; Hall, J.; Hall, T. A.; Hanna, D.;
Hillas, A. M.; Holder, J.; Horan, D.; Jarvis, A.; Jordan, M.; Kenny,
G. E.; Kertzman, M.; Kieda, D.; Kildea, J.; Knapp, J.; Krawczynski,
H.; Krennrich, F.; Lang, M. J.; Le Bohec, S.; Linton, E.; Lloyd-Evans,
J.; Milovanovic, A.; McEnery, J.; Moriarty, P.; Muller, D.; Nagai,
T.; Nolan, S.; Ong, R. A.; Pallassini, R.; Petry, D.; Power-Mooney,
B.; Quinn, J.; Quinn, M.; Ragan, K.; Rebillot, P.; Reynolds, P. T.;
Rose, H. J.; Schroedter, M.; Sembroski, G. H.; Swordy, S. P.; Syson,
A.; Vassiliev, V. V.; Wakely, S. P.; Walker, G.; Weekes, T. C.;
Zweerink, J.
Bibcode: 2004ApJ...608L..97K
Altcode: 2004astro.ph..3422K
We report a possible detection of TeV gamma rays from the Galactic
center by the Whipple 10 m gamma-ray telescope. Twenty-six hours of data
were taken over an extended period from 1995 through 2003 resulting
in a total significance of 3.7 σ. The measured excess corresponds
to an integral flux of 1.6×10-8+/-0.5×10-8
(stat)+/-0.3×10-8 (sys) photons m-2
s-1 above an energy of 2.8 TeV, roughly 40% of the flux from
the Crab Nebula at this energy. The 95% confidence region has an angular
extent of about 15' and includes the position of Sgr A*. The detection
is consistent with a point source and shows no evidence of variability.
Title: The Distribution and Variability of Chromospheric Activity
in a Large Sample of Solar Analogs
Authors: Hall, J. C.; Lockwood, G. W.
Bibcode: 2004AAS...204.0302H
Altcode: 2004BAAS...36..671H
We present the results of approximately 9,000 spectroscopic observations
of the chromospheric Ca II H&K emission in a magnitude-limited
sample of solar analog stars, as well as nearly 1,000 identical
observations of the Sun, taken between 1994 and 2003. We discuss the
behavior of Ca variations in the nearest solar analogs relative to the
contemporaneous solar record, reconcile our flux measurements with Ca K
indices from the NSO as well as Mt. Wilson S, and examine the general
activity level in cycling versus non-cycling stars. Although
approximately one third of the stars in the sample show little or no
long-term cyclic variability, we find that a lack of such variability
does not imply very low levels of magnetic activity. Non-cycling stars
exhibit a variety of baseline activity levels, from near-zero magnetic
activity to levels comparable to that of the active Sun. We do not find
significant evidence for transitions to or from a Maunder minimum state
in our current stellar sample, or that such transitions are accompanied
by a significant change in a star's overall activity level. This
work has been supported by the National Science Foundation.
Title: Measurement of the Total Active 8B Solar Neutrino
Flux at the Sudbury Neutrino Observatory with Enhanced Neutral
Current Sensitivity
Authors: Ahmed, S. N.; Anthony, A. E.; Beier, E. W.; Bellerive,
A.; Biller, S. D.; Boger, J.; Boulay, M. G.; Bowler, M. G.; Bowles,
T. J.; Brice, S. J.; Bullard, T. V.; Chan, Y. D.; Chen, M.; Chen, X.;
Cleveland, B. T.; Cox, G. A.; Dai, X.; Dalnoki-Veress, F.; Doe, P. J.;
Dosanjh, R. S.; Doucas, G.; Dragowsky, M. R.; Duba, C. A.; Duncan,
F. A.; Dunford, M.; Dunmore, J. A.; Earle, E. D.; Elliott, S. R.;
Evans, H. C.; Ewan, G. T.; Farine, J.; Fergani, H.; Fleurot, F.;
Formaggio, J. A.; Fowler, M. M.; Frame, K.; Fulsom, B. G.; Gagnon,
N.; Graham, K.; Grant, D. R.; Hahn, R. L.; Hall, J. C.; Hallin,
A. L.; Hallman, E. D.; Hamer, A. S.; Handler, W. B.; Hargrove, C. K.;
Harvey, P. J.; Hazama, R.; Heeger, K. M.; Heintzelman, W. J.; Heise,
J.; Helmer, R. L.; Hemingway, R. J.; Hime, A.; Howe, M. A.; Jagam,
P.; Jelley, N. A.; Klein, J. R.; Kos, M. S.; Krumins, A. V.; Kutter,
T.; Kyba, C. C.; Labranche, H.; Lange, R.; Law, J.; Lawson, I. T.;
Lesko, K. T.; Leslie, J. R.; Levine, I.; Luoma, S.; MacLellan, R.;
Majerus, S.; Mak, H. B.; Maneira, J.; Marino, A. D.; McCauley, N.;
McDonald, A. B.; McGee, S.; McGregor, G.; Mifflin, C.; Miknaitis,
K. K.; Miller, G. G.; Moffat, B. A.; Nally, C. W.; Nickel, B. G.;
Noble, A. J.; Norman, E. B.; Oblath, N. S.; Okada, C. E.; Ollerhead,
R. W.; Orrell, J. L.; Oser, S. M.; Ouellet, C.; Peeters, S. J.; Poon,
A. W.; Robertson, B. C.; Robertson, R. G.; Rollin, E.; Rosendahl,
S. S.; Rusu, V. L.; Schwendener, M. H.; Simard, O.; Simpson, J. J.;
Sims, C. J.; Sinclair, D.; Skensved, P.; Smith, M. W.; Starinsky,
N.; Stokstad, R. G.; Stonehill, L. C.; Tafirout, R.; Takeuchi, Y.;
Tešić, G.; Thomson, M.; Thorman, M.; van Berg, R.; van de Water,
R. G.; Virtue, C. J.; Wall, B. L.; Waller, D.; Waltham, C. E.; Tseung,
H. Wan; Wark, D. L.; West, N.; Wilhelmy, J. B.; Wilkerson, J. F.;
Wilson, J. R.; Wouters, J. M.; Yeh, M.; Zuber, K.
Bibcode: 2004PhRvL..92r1301A
Altcode: 2003nucl.ex...9004C; 2003nucl.ex...9004S
The Sudbury Neutrino Observatory has precisely determined the
total active (νx) 8B solar neutrino
flux without assumptions about the energy dependence of the
νe survival probability. The measurements were made
with dissolved NaCl in heavy water to enhance the sensitivity
and signature for neutral-current interactions. The flux
is found to be 5.21±0.27(stat)±0.38(syst)×106
cm-2 s-1, in agreement with previous
measurements and standard solar models. A global analysis
of these and other solar and reactor neutrino results yields
Δm2=7.1+1.2-0.6×10-5
eV2 and θ=32.5+2.4-2.3
degrees. Maximal mixing is rejected at the equivalent of 5.4 standard
deviations.
Title: VERITAS: the Very Energetic Radiation Imaging Telescope
Array System
Authors: Krennrich, F.; Bond, I. H.; Boyle, P. J.; Bradbury, S. M.;
Buckley, J. H.; Carter-Lewis, D.; Celik, O.; Cui, W.; Daniel, M.;
D'Vali, M.; de la Calle Perez, I.; Duke, C.; Falcone, A.; Fegan, D. J.;
Fegan, S. J.; Finley, J. P.; Fortson, L. F.; Gaidos, J.; Gammell,
S.; Gibbs, K.; Gillanders, G. H.; Grube, J.; Hall, J.; Hall, T. A.;
Hanna, D.; Hillas, A. M.; Holder, J.; Horan, D.; Jarvis, A.; Jordan,
M.; Kenny, G. E.; Kertzman, M.; Kieda, D.; Kildea, J.; Knapp, J.;
Kosack, K.; Krawczynski, H.; Lang, M. J.; LeBohec, S.; Linton, E.;
Lloyd-Evans, J.; Milovanovic, A.; Moriarty, P.; Müller, D.; Nagai,
T.; Nolan, S.; Ong, R. A.; Pallassini, R.; Petry, D.; Power-Mooney,
B.; Quinn, J.; Quinn, M.; Ragan, K.; Rebillot, P.; Reynolds, P. T.;
Rose, H. J.; Schroedter, M.; Sembroski, G.; Swordy, S. P.; Syson,
A.; Vassiliev, V. V.; Walker, G.; Wakely, S. P.; Weekes, T. C.;
Zweerink, J.
Bibcode: 2004NewAR..48..345K
Altcode:
The Very Energetic Radiation Imaging Telescope Array System (VERITAS)
is the major next generation imaging atmospheric Cherenkov γ-ray
telescope in the western hemisphere and will be located in southern
Arizona nearby Kitt Peak National Observatory. The VERITAS observatory
will provide unprecedented sensitivity to photon energies between 50
GeV and 50 TeV. The first stage is an array of four telescopes to be
fully operational in early 2006, with an expansion to seven telescopes
envisioned for 2008. The construction of a prototype telescope is
underway, for which first light is expected in Fall 2003. The technical
concept is outlined and a progress report is given.
Title: Mars Analog Rio Tinto Experiment (MARTE): 2003 Drilling
Campaign to Search for a Subsurface Biosphere at Rio Tinto Spain
Authors: Stoker, C.; Dunagan, S.; Stevens, T.; Amils, R.;
Gómez-Elvira, J.; Fernández, D.; Hall, J.; Lynch, K.; Cannon, H.;
Zavaleta, J.; Glass, B.; Lemke, L.
Bibcode: 2004LPI....35.2025S
Altcode:
The results of an drilling experiment to search for a subsurface
biosphere in a pyritic mineral deposit at Rio Tinto, Spain, are
described. The experiment provides ground truth for a simulation of
a Mars drilling mission to search for subsurface life.
Title: Constraints on the Very High Energy Emission from BL Lacertae
Objects
Authors: Horan, D.; Badran, H. M.; Bond, I. H.; Boyle, P. J.; Bradbury,
S. M.; Buckley, J. H.; Carter-Lewis, D. A.; Catanese, M.; Celik, O.;
Cui, W.; Daniel, M.; D'Vali, M.; de la Calle Perez, I.; Duke, C.;
Falcone, A.; Fegan, D. J.; Fegan, S. J.; Finley, J. P.; Fortson,
L. F.; Gaidos, J. A.; Gammell, S.; Gibbs, K.; Gillanders, G. H.;
Grube, J.; Hall, J.; Hall, T. A.; Hanna, D.; Hillas, A. M.; Holder,
J.; Jarvis, A.; Jordan, M.; Kenny, G. E.; Kertzman, M.; Kieda, D.;
Kildea, J.; Knapp, J.; Kosack, K.; Krawczynski, H.; Krennrich, F.;
Lang, M. J.; Le Bohec, S.; Linton, E.; Lloyd-Evans, J.; Milovanovic,
A.; Moriarty, P.; Muller, D.; Nagai, T.; Nolan, S.; Ong, R. A.;
Pallassini, R.; Petry, D.; Power-Mooney, B.; Quinn, J.; Quinn, M.;
Ragan, K.; Rebillot, P.; Reynolds, P. T.; Rose, H. J.; Schroedter,
M.; Sembroski, G. H.; Swordy, S. P.; Syson, A.; Vassiliev, V. V.;
Wakely, S. P.; Walker, G.; Weekes, T. C.; Zweerink, J.
Bibcode: 2004ApJ...603...51H
Altcode: 2003astro.ph.11397H
We present results from observations of 29 BL Lacertae objects, taken
with the Whipple Observatory 10 m gamma-ray telescope between 1995 and
2000. The observed objects are mostly at low redshift (z<0.2), but
observations of objects of up to z=0.444 are also reported. Five of the
objects are EGRET sources and two are unconfirmed TeV sources. Three of
the confirmed sources of extragalactic TeV gamma rays were originally
observed as part of this survey and have been reported elsewhere. No
significant excesses are detected from any of the other objects
observed, on timescales of days, months, or years. We report 99.9%
confidence level flux upper limits for the objects for each observing
season. The flux upper limits are typically 20% of the Crab flux,
although for some sources, limits as sensitive as 6% of the Crab
flux were derived. The results are consistent with the synchrotron
self-Compton model predictions considered in this work.
Title: Scientific Ballooning at the Planets
Authors: Cutts, J.; Beauchamp, P.; Elfes, A.; Hall, J.; Johnson, T.;
Jones, J.; Kerzhanovich, V.; Yavrouian, A.; Zimmerman, W.
Bibcode: 2004cosp...35.2466C
Altcode: 2004cosp.meet.2466C
NASA's Solar System Exploration Roadmap published in May 2003 calls for
an investment in aerial mobility in planetary atmospheres to enable key
scientific observations at Titan, Venus and Mars. In the case of Venus,
the only planet so far explored by balloon, future mission prospects
range from extended reconnaissance missions in the high atmosphere
to the use of balloons in sample return. At Titan, a balloon or blimp
mission might be the next logical step in the exploration of the surface
and atmosphere of that body to follow the Cassini observations of Titan
from Saturn orbit that begin in July 2004 and the Huygens probe entry of
January 05. An aerial mission to the Titan surface would most likely be
coupled with a means of sampling potential organic lakes and/or the icy
surface. At Mars, balloon missions provide the opportunity to traverse
much longer distances than surface missions like the Mars rover and to
exploit a vantage point within a few kilometers of the surface to make
unique scientific observations. Except for technologies for balloons
themselves and their aerial deployment where significant progress has
been made recently, a key technology for planetary lighter than air
vehicles, especially for Titan, is autonomy. Much higher levels of
autonomy than those to date in planetary exploration will be needed
for robust scientifically productive exploration. In this presentation
we review the mission opportunities and the key technology challenges.
Title: An Aerobot for Global In Situ Exploration of Titan
Authors: Hall, J.; Kerzhanovich, V.; Yavrouian, A.; Jones, J.; White,
C.; Dudik, B.; Elfes, A.
Bibcode: 2004cosp...35..198H
Altcode: 2004cosp.meet..198H
This paper describes the design and component testing of an aerobot
that will be capable of global in situ exploration of Saturn's moon,
Titan, over a 6 to 12 month mission lifetime. The proposed aerobot
is a propeller-driven, buoyant vehicle that resembles terrestrial
airships. However, the extremely cold Titan environment requires the use
of cryogenic materials of construction and careful thermal design for
protection of temperature-sensitive payload elements. Multiple candidate
balloon materials have been identified based on extensive laboratory
testing at 77 K. The most promising materials to date are laminates
comprised of polyester fabrics and/or films with areal densities in
the range of 40-100 g/m^2. The aerobot hull is a streamlined ellipsoid
12 meters in length with a maximum diameter of 3 meters. The enclosed
volume of 56 m^3 is sufficient to float a mass of 200 kg at a maximum
altitude of 8 km at Titan. Forward and aft ballonets are located
inside the hull to enable the aerobot to descend to the surface while
preserving a fully inflated streamlined shape. Altitude changes are
effected primarily through thrust vectoring of the twin main propellers,
with pressure modulated buoyancy change via the ballonets available as a
slower backup option. A total of 100 W of electrical power is provided
to the vehicle by a radioisotope thermal generator. Up to half of this
power is available to the propulsion system to generate a top flight
speed in the range of 1-2 m/s. This speed is expected to be greater
than the near surface winds at Titan, enabling the aerobot to fly to and
hover over targets of interest. A preliminary science payload has been
devised for the aerobot to give it the capability for aerial imaging
of the surface, atmospheric observations and sampling, and surface
sample acquisition and analysis. Targeting, hovering, surface sample
acquisition and vehicle health monitoring and reflexive safing actions
will all require significant on-board autonomy due to the over two hour
round trip light time between Titan and Earth. An autonomy architecture
and a core set of perception, reasoning and control technologies is
under development using a free-flying airship testbed of approximately
the same size as the proposed Titan aerobot. Data volume from the Titan
science mission is expected to be on the order of 100-300 Mbit per day
transmitted either direct to Earth through an 0.8 m high gain antenna or
via an orbiter relay using an omni-directional antenna on the aerobot.
Title: Search for High-Energy Gamma Rays from an X-Ray-selected
Blazar Sample
Authors: de la Calle Pérez, I.; Bond, I. H.; Boyle, P. J.; Bradbury,
S. M.; Buckley, J. H.; Carter-Lewis, D. A.; Celik, O.; Cui, W.;
Dowdall, C.; Duke, C.; Falcone, A.; Fegan, D. J.; Fegan, S. J.;
Finley, J. P.; Fortson, L.; Gaidos, J. A.; Gibbs, K.; Gammell,
S.; Hall, J.; Hall, T. A.; Hillas, A. M.; Holder, J.; Horan,
D.; Jordan, M.; Kertzman, M.; Kieda, D.; Kildea, J.; Knapp, J.;
Kosack, K.; Krawczynski, H.; Krennrich, F.; LeBohec, S.; Linton,
E. T.; Lloyd-Evans, J.; Moriarty, P.; Müller, D.; Nagai, T. N.;
Ong, R. A.; Page, M.; Pallassini, R.; Petry, D.; Power-Mooney, B.;
Quinn, J.; Rebillot, P.; Reynolds, P. T.; Rose, H. J.; Schroedter,
M.; Sembroski, G. H.; Swordy, S. P.; Vassiliev, V. V.; Wakely, S. P.;
Walker, G.; Weekes, T. C.
Bibcode: 2003ApJ...599..909D
Altcode: 2003astro.ph..9063D; 2003astro.ph..9063P
Our understanding of blazars has been greatly increased in recent years
by extensive multiwavelength observations, particularly in the radio,
X-ray, and gamma-ray regions. Over the past decade the Whipple 10
m telescope has contributed to this with the detection of five BL
Lacertae objects at very high gamma-ray energies. The combination
of multiwavelength data has shown that blazars follow a well-defined
sequence in terms of their broadband spectral properties. Together with
providing constraints on emission models, this information has yielded
a means by which potential sources of TeV emission may be identified
and predictions made as to their possible gamma-ray flux. We have
used the Whipple telescope to search for TeV gamma-ray emission from
eight objects selected from a list of such candidates. No evidence
has been found for very high energy emission from the objects in our
sample, and upper limits have been derived for the mean gamma-ray
flux above 390 GeV. These flux upper limits are compared with the
model predictions, and the implications of our results for future
observations are discussed.
Title: The VERITAS Prototype
Authors: Wakely, S. P.; Bond, I. H.; Boyle, P. J.; Bradbury, S. M.;
Carter-Lewis, D.; Celik, O.; Cui, W.; Daniel, M.; D'Vali, M.; de la
Calle Perez, I.; Duke, C.; Falcone, A.; Fegan, D. J.; Fegan, S. J.;
Finley, J. P.; Fortson, L. F.; Gaidos, J.; Gammell, S.; Gibbs, K.;
Gillanders, G. H.; Grube, J.; Hall, J.; Hall, T. A.; Hanna, D.;
Hillas, A. M.; Holder, J.; Horan, D.; Jarvis, A.; Jordan, M.; Kenny,
G. E.; Kertzman, M.; Kieda, D.; Kildea, J.; Knapp, J.; Kosack, K.;
Krawczynski, H.; Krennrich, F.; Lang, M. J.; LeBohec, S.; Linton, E.;
Lloyd-Evans, J.; Milovanovic, A.; Moriarty, P.; Muller, D.; Nagai,
T.; Nolan, S.; Ong, R. A.; Pallassini, R.; Petry, D.; Power-Mooney,
B.; Quinn, J.; Quinn, M.; Ragan, K.; Rebillot, P.; Reynolds, P. T.;
Rose, H. J.; Schroedter, M.; Sembroski, G.; Swordy, S. P.; Syson,
A.; Vassiliev, V. V.; Walker, G.; Weekes, T. C.; Zweerink, J.
Bibcode: 2003ICRC....5.2803W
Altcode: 2003ICRC...28.2803W
We give an up date on the status of the prototype telescope of the
Very Energetic Radiation Imaging telescope Array System (VERITAS), a
next-generation ˇ atmospheric imaging Cerenkov array currently under
construction in southern Arizona. VERITAS will feature significant
improvements over previous instruments, including better energy
resolution, lower energy threshold, improved an-
Title: Calibration Systems for the VERITAS Observatory
Authors: Allen, D.; Hall, J.; Kieda, D. B.; Nagai, T.; Snure, M.;
Vassiliev, V. V.; Walker, G.
Bibcode: 2003ICRC....5.2831A
Altcode: 2003ICRC....5.2831K; 2003ICRC...28.2831A
We describe the calibration systems used in the VERITAS Imaging Atmoˇ
spheric Cerenkov detector. Calibration systems include a charge
injection system for measuring electronic gain and testing pattern
trigger functionality, optical injection for flat-fielding PMT gains
as well as measuring mirror reflectivity, and atmospheric monitoring
for measuring changes in atmospheric attenuation, including ground
level aerosol concentrations.
Title: Search for Very High Energy Gamma Rays from an X-Ray Selected
Blazar Sample
Authors: de la Calle Perez, I.; Bond, I. H.; Boyle, P. J.; Bradbury,
S. M.; Buckley, J. H.; Carter-Lewis, D.; Celik, O.; Cui, W.; Daniel,
M.; D'Vali, M.; Duke, C.; Falcone, A.; Fegan, D. J.; Fegan, S. J.;
Finley, J. P.; Fortson, L. F.; Gaidos, J.; Gammell, S.; Gibbs, K.;
Gillanders, G. H.; Grube, J.; Hall, J.; Hall, T. A.; Hanna, D.;
Hillas, A. M.; Holder, J.; Horan, D.; Jarvis, A.; Jordan, M.; Kenny,
G. E.; Kertzman, M.; Kieda, D.; Kildea, J.; Knapp, J.; Kosack, K.;
Krawczynski, H.; Krennrich, F.; Lang, M. J.; LeBohec, S.; Linton,
E.; Lloyd-Evans, J.; Milovanovic, A.; Moriarty, P.; Muller D.; Nagai,
T.; Nolan, S.; Ong, R. A.; Pallassini, R.; Petry, D.; Power-Mooney,
B.; Quinn, J.; Quinn, M.; Ragan, K.; Rebillot, P.; Reynolds, P. T.;
Rose, H. J.; Schroedter, M.; Sembroski, G.; Swordy, S. P.; Syson,
A.; Vassiliev, V. V.; Wakely, S. P.; Walker, G.; Weekes, T. C.;
Zweerink, J.
Bibcode: 2003ICRC....5.2571D
Altcode: 2003ICRC...28.2571D; 2003ICRC....5.2571H; 2003astro.ph..5573D;
2003astro.ph..5573P
In recent years, blazar surveys at radio and X-ray energies
have greatly increased our understanding of this type of active
galaxy. The combination of multi-wavelength data has shown that
blazars follow a well defined sequence in terms of their broad band
spectral properties. Together with increasingly detailed emission
models, this information has provided not only to ols with which to
identify potential sources of TeV emission but also predictions of
their gamma-ray flux. A list of such candidates has been used in this
work to investigate the best targets for TeV observations. Observations
reported here have resulted in upper limits which do not conflict with
the latest model predictions.
Title: Signal Cable Selection for the VERITAS Observatory
Authors: Kieda, D. B.; Allen, D.; Hall, J.; Nagai, T.; Snure, M.;
Vassilev, V. V.; Walker, G.
Bibcode: 2003ICRC....5.2835A
Altcode: 2003ICRC....5.2835K; 2003ICRC...28.2835A
We describe electrical and mechanical tests performed on various coaxial
cables to characterize their electrical properties and reliabilities. We
use these properties, combined with additional information concerning
weight, diameter, and cost, to select the optimum signal cables for
the VERITAS observatory. We find significant advantages in using
RG-59 Coaxial cable over traditional RG-58 cable. Stranded core RG-59
results in an 30-50% increase in effective mirror area over RG 58;
solid core RG59 would result in a 84% increase in effective mirror
area. Reliability tests demonstrate that although RG59 solid core will
fatigue and fail after repeated twisting, this fatigue would result in a
loss of approximately 10 cables over the lifetime of the VERITAS array.
Title: Search for TeV Emission at the Location of Milagro Sky Survey
Hot Spot Using the Whipple Gamma-Ray Telescope
Authors: Falcone, A.; Bond, I. H.; Boyle, P. J.; Bradbury, S. M.;
Buckley, J. H.; Carter-Lewis, D.; Celik, O.; Cui, W.; Daniel, M.;
D'Vali, M.; de la Calle Perez, I.; Duke, C.; Fegan, D. J.; Fegan,
S. J.; Finley, J. P.; Fortson, L. F.; Gaidos, J.; Gammell, S.; Gibbs,
K.; Gillanders, G. H.; Grube, J.; Hall, J.; Hall, T. A.; Hanna, D.;
Hillas, A. M.; Holder, J.; Horan, D.; Jarvis, A.; Jordan, M.; Kenny,
G. E.; Kertzman, M.; Kieda, D.; Kildea, J.; Knapp, J.; Kosack, K.;
Krawczynski, H.; Krennrich, F.; Lang, M. J.; LeBohec, S.; Linton,
E.; Lloyd-Evans, J.; Milovanovic, A.; Moriarty, P.; Muller D.; Nagai,
T.; Nolan, S.; Ong, R. A.; Pallassini, R.; Petry, D.; Power-Mooney,
B.; Quinn, J.; Quinn, M.; Ragan, K.; Rebillot, P.; Reynolds, P. T.;
Rose, H. J.; Schroedter, M.; Sembroski, G.; Swordy, S. P.; Syson,
A.; Vassiliev, V. V.; Wakely, S. P.; Walker, G.; Weekes, T. C.;
Zweerink, J.
Bibcode: 2003ICRC....5.2579F
Altcode: 2003ICRC...28.2579F; 2003astro.ph..5575F; 2003ICRC....5.2579G
A recent report from the Milagro collab oration included an all-sky
map created using one year of data from Milagro (peak sensitivity
at 3-4 TeV for Crab-like spectra). This map included an unidentified
excess that was brighter than the Crab and was the second brightest
spot on the map. The hot spot was within the error box of the EGRET
unidentified source 3EG J0520+2556. No strong and steady emission was
detected by the Whipple telescope at, or in the vicinity of, either
position. The 95% confidence level flux upper limits from Whipple
observations at the locations of the Milagro hot spot and the EGRET
UnID position are 0.09 Crabs and 0.14 Crabs, respectively.
Title: Search for TeV Annihilation Radiation from Supersymmetric
Dark Matter in nearby Galaxies
Authors: Vassiliev, V. V.; Bond, I. H.; Boyle, P. J.; Bradbury, S. M.;
Buckley, J. H.; Carter-Lewis, D.; Celik, O.; Cui, W.; Daniel, M.;
D'Vali, M.; de la Calle Perez, I.; Duke, C.; Falcone, A.; Fegan, D. J.;
Fegan, S. J.; Finley, J. P.; Fortson, L. F.; Gaidos, J.; Gammell, S.;
Gibbs, K.; Gillanders, G. H.; Grube, J.; Hall, J.; Hall, T. A.; Hanna,
D.; Hillas, A. M.; Holder, J.; Horan, D.; Jarvis, A.; Jordan, M.;
Kenny, G. E.; Kertzman, M.; Kieda, D.; Kildea, J.; Knapp, J.; Kosack,
K.; Krawczynski, H.; Krennrich, F.; Lang, M. J.; LeBohec, S.; Linton,
E.; Lloyd-Evans, J.; Milovanovic, A.; Moriarty, P.; Muller D.; Nagai,
T.; Nolan, S.; Ong, R. A.; Pallassini, R.; Petry, D.; Power-Mooney,
B.; Quinn, J.; Quinn, M.; Ragan, K.; Rebillot, P.; Reynolds, P. T.;
Rose, H. J.; Schroedter, M.; Sembroski, G.; Swordy, S. P.; Syson, A.;
Wakely, S. P.; Walker, G.; Weekes, T. C.; Zweerink, J.; Bromley, B. C.
Bibcode: 2003ICRC....5.2679V
Altcode: 2003ICRC...28.2679V; 2003astro.ph..5584V
During the 2002-2003 observing season the Whipple 10m imaging atmoˇ
spheric Cherenkov telescope was used to search for dark matter
annihilation radiation in four nearby galaxies: M32, M33, Draco,
and Ursa Minor. Scientific motivations for this choice of targets are
discussed as well as accumulated exposure. The analysis results are
to be reported in the conference presentation.
Title: Observation of M87 with the Whipple 10m Telescope
Authors: LeBohec, S.; Bond, I. H.; Boyle, P. J.; Bradbury, S. M.;
Buckley, J. H.; Carter-Lewis, D.; Celik, O.; Cui, W.; Daniel, M.;
D'Vali, M.; de la Calle Perez, I.; Duke, C.; Falcone, A.; Fegan, D. J.;
Fegan, S. J.; Finley, J. P.; Fortson, L. F.; Gaidos, J.; Gammell,
S.; Gibbs, K.; Gillanders, G. H.; Grube, J.; Hall, J.; Hall, T. A.;
Hanna, D.; Hillas, A. M.; Holder, J.; Horan, D.; Jarvis, A.; Jordan,
M.; Kenny, G. E.; Kertzman, M.; Kieda, D.; Kildea, J.; Knapp, J.;
Kosack, K.; Krawczynski, H.; Krennrich, F.; Lang, M. J.; Linton, E.;
Lloyd-Evans, J.; Milovanovic, A.; Moriarty, P.; Muller, D.; Nagai,
T.; Nolan, S.; Ong, R. A.; Pallassini, R.; Petry, D.; Power-Mooney,
B.; Quinn, J.; Quinn, M.; Ragan, K.; Rebillot, P.; Reynolds, P. T.;
Rose, H. J.; Schroedter, M.; Sembroski, G.; Swordy, S. P.; Syson,
A.; Vassiliev, V. V.; Wakely, S. P.; Walker, G.; Weekes, T. C.;
Zweerink, J.
Bibcode: 2003ICRC....5.2627L
Altcode: 2003astro.ph..5582L; 2003ICRC...28.2627L
The Whipple 10-m telescope was used to observe M87 since 2000. No
significant gamma-ray signal was found and upper limits compared to
the HEGRA detection suggest the source may be variable. We found weak
evidence for a correlation with the X-ray activity in 2000-2001 but
this tendency did not persist in 2002-2003.
Title: VHE Observations of BL Lacertae Objects: 1995-2000
Authors: Horan, D.; Catanese, M. A.; Bond, I. H.; Boyle, P. J.;
Bradbury, S. M.; Buckley, J. H.; Carter-Lewis, D.; Celik, O.; Cui, W.;
Daniel, M.; D'Vali, M.; de la Calle Perez, I.; Duke, C.; Falcone, A.;
Fegan, D. J.; Fegan, S. J.; Finley, J. P.; Fortson, L. F.; Gaidos, J.;
Gammell, S.; Gibbs, K.; Gillanders, G. H.; Grube, J.; Hall, J.; Hall,
T. A.; Hanna, D.; Hillas, A. M.; Holder, J.; Jarvis, A.; Jordan, M.;
Kenny, G. E.; Kertzman, M.; Kieda, D.; Kildea, J.; Knapp, J.; Kosack,
K.; Krawczynski, H.; Krennrich, F.; Lang, M. J.; LeBohec, S.; Linton,
E.; Lloyd-Evans, J.; Milovanovic, A.; Moriarty, P.; Muller, D.; Nagai,
T.; Nolan, S.; Ong, R. A.; Pallassini, R.; Petry, D.; Power-Mooney,
B.; Quinn, J.; Quinn, M.; Ragan, K.; Rebillot, P.; Reynolds, P. T.;
Rose, H. J.; Schroedter, M.; Sembroski, G.; Swordy, S. P.; Syson,
A.; Vassiliev, V. V.; Wakely, S. P.; Walker, G.; Weekes, T. C.;
Zweerink, J.
Bibcode: 2003ICRC....5.2567H
Altcode: 2003ICRC...28.2567H
The results of observations of 29 BL Lacertae objects taken with the
Whipple Observatory 10 m gamma-ray telescope between 1995 and 2000
are presented.
Title: A Search for Pulsed TeV Gamma-Ray Emission from the Crab
Pulsar Using the Whipple High Resolution GRANITE III Camera
Authors: Kildea, J.; Bond, I. H.; Boyle, P. J.; Bradbury, S. M.;
Buckley, J. H.; Carter-Lewis, D.; Celik, O.; Cui, W.; Daniel, M.;
D'Vali, M.; de la Calle Perez, I.; Duke, C.; Falcone, A.; Fegan,
D. J.; Fegan, S. J.; Finley, J. P.; Fortson, L. F.; Gaidos, J.;
Gammell, S.; Gibbs, K.; Gillanders, G. H.; Grube, J.; Hall, J.; Hall,
T. A.; Hanna, D.; Hillas, A. M.; Holder, J.; Horan, D.; Jarvis, A.;
Jordan, M.; Kenny, G. E.; Kertzman, M.; Kieda, D.; Knapp, J.; Kosack,
K.; Krawczynski, H.; Krennrich, F.; Lang, M. J.; LeBohec, S.; Linton,
E.; Lloyd-Evans, J.; Milovanovic, A.; Moriarty, P.; Muller D.; Nagai,
T.; Nolan, S.; Ong, R. A.; Pallassini, R.; Petry, D.; Power-Mooney,
B.; Quinn, J.; Quinn, M.; Ragan, K.; Rebillot, P.; Reynolds, P. T.;
Rose, H. J.; Schroedter, M.; Sembroski, G.; Swordy, S. P.; Syson,
A.; Vassiliev, V. V.; Wakely, S. P.; Walker, G.; Weekes, T. C.;
Zweerink, J.
Bibcode: 2003ICRC....4.2377K
Altcode: 2003astro.ph..5580K; 2003ICRC...28.2377K; 2003ICRC....4.2377G
We present the results of a search for pulsed TeV emission from the
Crab pulsar using 97 hours of data recorded with the high-resolution
GRANITE I I I camera of the Whipple 10 m gamma-ray telescope.
Title: Whipple Observations of 1ES1959+650: An Update
Authors: Holder, J.; Bond, I. H.; Boyle, P. J.; Bradbury, S. M.;
Buckley, J. H.; Carter-Lewis, D.; Celik, O.; Cui, W.; Daniel, M.;
D'Vali, M.; de la Calle Perez, I.; Duke, C.; Falcone, A.; Fegan, D. J.;
Fegan, S. J.; Finley, J. P.; Fortson, L. F.; Gaidos, J.; Gammell,
S.; Gibbs, K.; Gillanders, G. H.; Grube, J.; Hall, J.; Hall, T. A.;
Hanna, D.; Hillas, A. M.; Horan, D.; Jarvis, A.; Jordan, M.; Kenny,
G. E.; Kertzman, M.; Kieda, D.; Kildea, J.; Knapp, J.; Kosack, K.;
Krawczynski, H.; Krennrich, F.; Lang, M. J.; LeBohec, S.; Linton, E.;
Lloyd-Evans, J.; Milovanovic, A.; Moriarty, P.; Muller, D.; Nagai,
T.; Nolan, S.; Ong, R. A.; Pallassini, R.; Petry, D.; Power-Mooney,
B.; Quinn, J.; Quinn, M.; Ragan, K.; Rebillot, P.; Reynolds, P. T.;
Rose, H. J.; Schroedter, M.; Sembroski, G.; Swordy, S. P.; Syson,
A.; Vassiliev, V. V.; Wakely, S. P.; Walker, G.; Weekes, T. C.;
Zweerink, J.
Bibcode: 2003ICRC....5.2619H
Altcode: 2003astro.ph..5577H; 2003ICRC...28.2619H
Strong flares of TeV gamma-ray emission up to a level of ∼ 5 Crab
were ˇ detected by the Whipple 10 m atmospheric Cerenkov telescope
from the BL Lacertae object 1ES1959+650 during May July 2002. We report
here the results of follow up observations during 2002 2003.
Title: Performance of the VERITAS-4 Array
Authors: Fegan, S. J.; Hall, J.; Vassiliev, V. V.
Bibcode: 2003ICRC....5.2847F
Altcode: 2003ICRC...28.2847F
We present the simulated characteristics of VERITAS-4, a four telescope
instrument, scheduled to be operational in 2005.
Title: Search for a WIMP Annihilation Signature in the Core of the
Globular Cluster M15
Authors: LeBohec, S.; Baltz, E. A.; Bond, I. H.; Boyle, P. J.;
Bradbury, S. M.; Buckley, J. H.; Carter-Lewis, D.; Celik, O.; Cui, W.;
Daniel, M.; D'Vali, M.; de la Calle Perez, I.; Duke, C.; Falcone, A.;
Fegan, D. J.; Fegan, S. J.; Finley, J. P.; Fortson, L. F.; Gaidos,
J.; Gammell, S.; Gibbs, K.; Gillanders, G. H.; Grube, J.; Hall, J.;
Hall, T. A.; Hanna, D.; Hillas, A. M.; Holder, J.; Horan, D.; Jarvis,
A.; Jordan, M.; Kenny, G. E.; Kertzman, M.; Kieda, D.; Kildea, J.;
Knapp, J.; Kosack, K.; Krawczynski, H.; Krennrich, F.; Lang, M. J.;
Linton, E.; Lloyd-Evans, J.; Milovanovic, A.; Moriarty, P.; Muller,
D.; Nagai, T.; Nolan, S.; Ong, R. A.; Pallassini, R.; Petry, D.;
Power-Mooney, B.; Quinn, J.; Quinn, M.; Ragan, K.; Rebillot, P.;
Reynolds, P. T.; Rose, H. J.; Schroedter, M.; Sembroski, G.; Swordy,
S. P.; Syson, A.; Vassiliev, V. V.; Wakely, S. P.; Walker, G.; Weekes,
T. C.; Zweerink, J.
Bibcode: 2003ICRC....4.2521L
Altcode: 2003ICRC...28.2521L; 2003astro.ph..5581L
The Whipple 10m Very High Energy gamma-ray telescope has been used to
search for indications of WIMP annihilation in the direction of the
globular cluster M15. The upper limits derived constrain the amount
of super-symmetric dark matter that may reside in globular clusters.
Title: Whipple Telescope Observations of Potential TeV Gamma-Ray
Sources Found by the Tibet Air Shower Array
Authors: Walker, G.; Bond, I. H.; Boyle, P. J.; Bradbury, S. M.;
Buckley, J. H.; Carter-Lewis, D.; Celik, O.; Cui, W.; Daniel, M.;
D'Vali, M.; de la Calle Perez, I.; Duke, C.; Falcone, A.; Fegan, D. J.;
Fegan, S. J.; Finley, J. P.; Fortson, L. F.; Gaidos, J.; Gammell, S.;
Gibbs, K.; Gillanders, G. H.; Grube, J.; Hall, J.; Hall, T. A.; Hanna,
D.; Hillas, A. M.; Holder, J.; Horan, D.; Jarvis, A.; Jordan, M.;
Kenny, G. E.; Kertzman, M.; Kieda, D.; Kildea, J.; Knapp, J.; Kosack,
K.; Krawczynski, H.; Krennrich, F.; Lang, M. J.; LeBohec, S.; Linton,
E.; Lloyd-Evans, J.; Milovanovic, A.; Moriarty, P.; Muller, D.; Nagai,
T.; Nolan, S.; Ong, R. A.; Pallassini, R.; Petry, D.; Power-Mooney,
B.; Quinn, J.; Quinn, M.; Ragan, K.; Rebillot, P.; Reynolds, P. T.;
Rose, H. J.; Schroedter, M.; Sembroski, G.; Swordy, S. P.; Syson,
A.; Vassiliev, V. V.; Wakely, S. P.; Weekes, T. C.; Zweerink, J.
Bibcode: 2003ICRC....5.2563W
Altcode: 2003ICRC...28.2563W
An all-sky survey performed with the Tibet Air Shower Array (Tib et AS)
has found a number of potential point sources of TeV gamma rays. If they
are steady sources, the implied Tibet AS fluxes should be visible with
strong significance to the Whipple 10-m gamma-ray telescope (E >
400 GeV) with only a short (5 hour) exposure. We have observed four
candidate directions from the Tibet-I I HD dataset for ∼5 hours each
with the Whipple telescope. In addition, we observed a new candidate
direction from the Tibet-I I I Phase 1 dataset for 7.5 hours. We have
found no corresponding excesses at the flux levels implied, and we
have set upper limits for each candidate.
Title: Hourly Spectral Variability of Mrk 421
Authors: Krennrich, F.; Bond, I. H.; Boyle, P. J.; Bradbury, S. M.;
Buckley, J. H.; Carter-Lewis, D.; Celik, O.; Cui, W.; Daniel, M.;
D'Vali, M.; de la Calle Perez, I.; Duke, C.; Falcone, A.; Fegan, D. J.;
Fegan, S. J.; Finley, J. P.; Fortson, L. F.; Gaidos, J.; Gammell, S.;
Gibbs, K.; Gillanders, G. H.; Grube, J.; Hall, J.; Hall, T. A.; Hanna,
D.; Hillas, A. M.; Holder, J.; Horan, D.; Jarvis, A.; Jordan, M.;
Kenny, G. E.; Kertzman, M.; Kieda, D.; Kildea, J.; Knapp, J.; Kosack,
K.; Krawczynski, H.; Lang, M. J.; LeBohec, S.; Linton, E.; Lloyd-Evans,
J.; Milovanovic, A.; Moriarty, P.; Muller, D.; Nagai, T.; Nolan, S.;
Ong, R. A.; Pallassini, R.; Petry, D.; Power-Mooney, B.; Quinn, J.;
Quinn, M.; Ragan, K.; Rebillot, P.; Reynolds, P. T.; Rose, H. J.;
Schroedter, M.; Sembroski, G.; Swordy, S. P.; Syson, A.; Vassiliev,
V. V.; Wakely, S. P.; Walker, G.; Weekes, T. C.; Zweerink, J.
Bibcode: 2003ICRC....5.2603K
Altcode: 2003ICRC...28.2603K; 2003astro.ph..5419K
Mrk 421 is the first TeV blazar found to exhibit significant spectral
variability during strong flaring activity, showing hardening of the
TeV spectrum in high emission states. Mrk 421 is also known to exhibit
flux variability on time scales as short as 15 minutes. In this paper
we present studies of hourly spectral variability of Mrk 421 in 2001
using data from the Whipple Observatory 10 m gamma-ray telescope.
Title: Very High Energy Observations of PSR B1823-13
Authors: Hall, T. A.; Bond, I. H.; Boyle, P. J.; Bradbury, S. M.;
Buckley, J. H.; Carter-Lewis, D.; Celik, O.; Cui, W.; Daniel, M.;
D'Vali, M.; de la Calle Perez, I.; Duke, C.; Falcone, A.; Fegan, D. J.;
Fegan, S. J.; Finley, J. P.; Fortson, L. F.; Gaidos, J.; Gammell,
S.; Gibbs, K.; Gillanders, G. H.; Grube, J.; Hall, J.; Hanna, D.;
Hillas, A. M.; Holder, J.; Horan, D.; Jarvis, A.; Jordan, M.; Kenny,
G. E.; Kertzman, M.; Kieda, D.; Kildea, J.; Knapp, J.; Kosack, K.;
Krawczynski, H.; Krennrich, F.; Lang, M. J.; LeBohec, S.; Linton,
E.; Lloyd-Evans, J.; Milovanovic, A.; Moriarty, P.; Muller D.; Nagai,
T.; Nolan, S.; Ong, R. A.; Pallassini, R.; Petry, D.; Power-Mooney,
B.; Quinn, J.; Quinn, M.; Ragan, K.; Rebillot, P.; Reynolds, P. T.;
Rose, H. J.; Schroedter, M.; Sembroski, G.; Swordy, S. P.; Syson,
A.; Vassiliev, V. V.; Wakely, S. P.; Walker, G.; Weekes, T. C.;
Zweerink, J.
Bibcode: 2003ICRC....4.2497H
Altcode: 2003astro.ph..5576H; 2003ICRC....4.2497M; 2003ICRC...28.2497H
To date three plerionic systems have been detected as emitters of very
energetic photons. As part of an ongoing study of pulsar systems at
the Whipple observatory, observations of the plerion PSR B1823-13 are
being conducted. Observations were made with the Whipple 10 m gamma-ray
telescope utilizing the high resolution, 490 pixel camera.
Title: Observations of Starburst Galaxies
Authors: Nagai, T.; Vassiliev, V. V.; Bond, I. H.; Boyle, P. J.;
Bradbury, S. M.; Buckley, J. H.; Carter-Lewis, D.; Celik, O.; Cui, W.;
Daniel, M.; D'Vali, M.; de la Calle Perez, I.; Duke, C.; Falcone, A.;
Fegan, D. J.; Fegan, S. J.; Finley, J. P.; Fortson, L. F.; Gaidos,
J.; Gammell, S.; Gibbs, K.; Gillanders, G. H.; Grube, J.; Hall, J.;
Hall, T. A.; Hanna, D.; Hillas, A. M.; Holder, J.; Jarvis, A.; Jordan,
M.; Kenny, G. E.; Kertzman, M.; Kieda, D.; Kildea, J.; Knapp, J.;
Kosack, K.; Krawczynski, H.; Krennrich, F.; Lang, M. J.; LeBohec, S.;
Linton, E.; Lloyd-Evans, J.; Milovanovic, A.; Moriarty, P.; Muller,
D.; Nolan, S.; Ong, R. A.; Pallassini, R.; Petry, D.; Power-Mooney,
B.; Quinn, J.; Quinn, M.; Ragan, K.; Rebillot, P.; Reynolds, P. T.;
Rose, H. J.; Schroedter, M.; Sembroski, G.; Swordy, S. P.; Syson,
A.; Wakely, S. P.; Walker, G.; Weekes, T. C.; Zweerink, J.
Bibcode: 2003ICRC....5.2635N
Altcode: 2003ICRC...28.2635N
The search for TeV gamma-ray radiation from starburst galaxies (SBGs)
has been conducted by the Whipple 10-m gamma-ray telescope from
January 2001 to March 2003. The regions with high star formation rates
(SFRs) observed in SBGs are frequently accompanied by high density
clouds of interstellar matter (ISM). This seems to create nearly
perfect conditions for generating diffuse gamma-ray radiation as high
energy cosmic rays interact with the ISM. If the current paradigm that
supernovae are the origin of high energy cosmic rays is valid, then star
forming regions rich in type Ib/c, I I supernovae may become the lab
oratories to test the hypothesis. Using the Whipple telescope we have
conducted a survey of several plausible SBGs selected based on their
distance, density of gas clouds, age of star forming regions, SFRs,
and magnetic fields, as well as the presence of radio flux and X-ray
point sources. We discuss the selection criteria based on gamma-ray
flux estimates, as well as the results of a novel spectrum dependent
analysis (to be reported during presentation) of SBG observations for
which a total exposure of 10-30 hours per source have been accumulated.
Title: Intensive TeV Gamma-Ray and X-Ray Observations of the Blazar
Mrk 421 in December 2002 and January 2003
Authors: Rebillot, P. F.; Hughes, S. B.; Bond, I. H.; Boyle, P. J.;
Bradbury, S. M.; Buckley, J. H.; Carter-Lewis, D.; Celik, O.; Cui, W.;
Daniel, M.; D'Vali, M.; de la Calle Perez, I.; Duke, C.; Falcone,
A.; Fegan, D. J.; Fegan, S. J.; Finley, J. P.; Fortson, L. F.;
Gaidos, J.; Gammell, S.; Gibbs, K.; Gillanders, G. H.; Grube, J.;
Hall, J.; Hall, T. A.; Hanna, D.; Hillas, A. M.; Holder, J.; Horan,
D.; Jarvis, A.; Jordan, M.; Kenny, G. E.; Kertzman, M.; Kieda, D.;
Kildea, J.; Knapp, J.; Kosack, K.; Krawczynski, H.; Krennrich, F.;
Lang, M. J.; LeBohec, S.; Linton, E.; Lloyd-Evans, J.; Milovanovic,
A.; Moriarty, P.; Muller, D.; Nagai, T.; Nolan, S.; Ong, R. A.;
Pallassini, R.; Petry, D.; Power-Mooney, B.; Quinn, J.; Quinn, M.;
Ragan, K.; Reynolds, P. T.; Rose, H. J.; Schroedter, M.; Sembroski,
G.; Swordy, S. P.; Syson, A.; Vassiliev, V. V.; Wakely, S. P.; Walker,
G.; Weekes, T. C.; Zweerink, J.
Bibcode: 2003ICRC....5.2599R
Altcode: 2003ICRC...28.2599R; 2003astro.ph..5583R
We report on observations of Markarian 421 made with the Whipple 10m
ˇ erenkov telescope and the RXTE satellite during a multi-wavelength
campaign C in December 2002 and January 2003, initiated by a Whipple
target of opportunity. The observations revealed several flares with
flux levels between 1 and 2 times the flux of the Crab Nebula. We
will discuss the temporal properties, including evidence of X-ray/TeV
gamma-ray flux correlation.
Title: Veritas CFDs
Authors: Hall, J.; Vassiliev, V. V.; Kieda, D. B.; Moses, J.; Nagai,
T.; Smith, J.
Bibcode: 2003ICRC....5.2851H
Altcode: 2003ICRC....5.2851V; 2003ICRC...28.2851H
The Level 1 (pixel) trigger of a VERITAS telescope is described. The
trigger uses a constant fraction discriminator (CFD) to decrease VERITAS
operation energy threshold by reducing the coincidence resolving time
between neighb oring pixels to ∼ 5 ns. We discuss the optimization of
the CFD design as well as ˇ unique requirements of the CFD application
in a Imaging Atmospheric Cerenkov telescope (IACT). We describe a novel
feedback circuit to provide real time optimization of CFD performance
under variable NSB conditions. Tests of the Level 1 trigger demonstrate
jitter < 1 ns with background noise values up to 0.8 pe/ns.
Title: TeV Observations of the Galactic Center
Authors: Kosack, K.; Bond, I. H.; Boyle, P. J.; Bradbury, S. M.;
Buckley, J. H.; Carter-Lewis, D.; Celik, O.; Cui, W.; Daniel, M.;
D'Vali, M.; de la Calle Perez, I.; Duke, C.; Falcone, A.; Fegan,
D. J.; Fegan, S. J.; Finley, J. P.; Fortson, L. F.; Gaidos, J.;
Gammell, S.; Gibbs, K.; Gillanders, G. H.; Grube, J.; Hall, J.; Hall,
T. A.; Hanna, D.; Hillas, A. M.; Holder, J.; Horan, D.; Jarvis, A.;
Jordan, M.; Kenny, G. E.; Kertzman, M.; Kieda, D.; Kildea, J.; Knapp,
J.; Krawczynski, H.; Krennrich, F.; Lang, M. J.; LeBohec, S.; Linton,
E.; Lloyd-Evans, J.; Milovanovic, A.; Moriarty, P.; Muller D.; Nagai,
T.; Nolan, S.; Ong, R. A.; Pallassini, R.; Petry, D.; Power-Mooney,
B.; Quinn, J.; Quinn, M.; Ragan, K.; Rebillot, P.; Reynolds, P. T.;
Rose, H. J.; Schroedter, M.; Sembroski, G.; Swordy, S. P.; Syson,
A.; Vassiliev, V. V.; Wakely, S. P.; Walker, G.; Weekes, T. C.;
Zweerink, J.
Bibcode: 2003ICRC....4.2513K
Altcode: 2003astro.ph..5592K; 2003ICRC....4.2513R; 2003ICRC...28.2513K
We present the results of 16 hours of ongoing observations of the
galactic center region (including Sagittarius A*) with the Whipple High
Energy GammaRay telescope. We apply a data analysis method optimized
for large zenith angle observations on an indep endent Crab Nebula
data set. We discuss possible systematic problems associated with
observations of extended sources in the galactic plane.
Title: Observations of H1426+428 from 1999 to 2002 with the Whipple
Observatory 10 m Telescope
Authors: Horan, D.; Bond, I. H.; Boyle, P. J.; Bradbury, S. M.;
Buckley, J. H.; Carter-Lewis, D.; Celik, O.; Cui, W.; Daniel, M.;
D'Vali, M.; de la Calle Perez, I.; Duke, C.; Falcone, A.; Fegan, D. J.;
Fegan, S. J.; Finley, J. P.; Fortson, L. F.; Gaidos, J.; Gammell,
S.; Gibbs, K.; Gillanders, G. H.; Grube, J.; Hall, J.; Hall, T. A.;
Hanna, D.; Hillas, A. M.; Holder, J.; Jarvis, A.; Jordan, M.; Kenny,
G. E.; Kertzman, M.; Kieda, D.; Kildea, J.; Knapp, J.; Kosack, K.;
Krawczynski, H.; Krennrich, F.; Lang, M. J.; LeBohec, S.; Linton, E.;
Lloyd-Evans, J.; Milovanovic, A.; Moriarty, P.; Muller, D.; Nagai,
T.; Nolan, S.; Ong, R. A.; Pallassini, R.; Petry, D.; Power-Mooney,
B.; Quinn, J.; Quinn, M.; Ragan, K.; Rebillot, P.; Reynolds, P. T.;
Rose, H. J.; Schroedter, M.; Sembroski, G.; Swordy, S. P.; Syson,
A.; Vassiliev, V. V.; Wakely, S. P.; Walker, G.; Weekes, T. C.;
Zweerink, J.
Bibcode: 2003ICRC....5.2647H
Altcode: 2003ICRC...28.2647H; 2003astro.ph..5579H
The BL Lacertae object H1426+428 is the most distant, confirmed
source of TeV gamma rays. At a redshift of 0.129, its detection at TeV
energies has important implications for estimating the density of the
extragalactic infra-red background radiation. H1426+428 was observed
extensively during the 2001/2002 observing season with the Whipple 10
m gamma-ray telescope. The results of these observations are presented
here and are combined with the results of previous observations made
between 1999 and 2001 at Whipple.
Title: Chromospheric Activity in Solar-Type Stars
Authors: Giampapa, M. S.; Hall, J. C.; Radick, R. R.; Baliunas, S. L.
Bibcode: 2003SPD....34.0710G
Altcode: 2003BAAS...35..821G
We present an update on the results of a survey of chromospheric
activity in the solar-age and solar-metallicity open cluster, M67. The
objective of the survey is to gain insight on the potential range of
amplitudes of the solar cycle through observations of solar analogs
that are presumably at random phases in their cycles of magnetic
activity. We find that there is a significant overlap of the levels
of Ca II H and K emission in the sun-like stars in M67 with the
range of activity seen in the contemporary solar cycle. However,
there are also stars that exhibit levels of activity outside of this
range, including stars that are "super-solar" in their Ca II H and
K emission. The implications of these results will be discussed. The data presented in this investigation were obtained with the
WIYN 3.5-m telescope on Kitt Peak. The WIYN Observatory is a joint
facility of the University of Wisconsin-Madison, Indiana University,
Yale University, and the NOAO. The NSO and the NOAO are operated by
AURA for the National Science Foundation.
Title: Detection of TeV Gamma Rays from the BL Lacertae Object 1ES
1959+650 with the Whipple 10 Meter Telescope
Authors: Holder, J.; Bond, I. H.; Boyle, P. J.; Bradbury, S. M.;
Buckley, J. H.; Carter-Lewis, D. A.; Cui, W.; Dowdall, C.; Duke,
C.; de la Calle Perez, I.; Falcone, A.; Fegan, D. J.; Fegan, S. J.;
Finley, J. P.; Fortson, L.; Gaidos, J. A.; Gibbs, K.; Gammell, S.;
Hall, J.; Hall, T. A.; Hillas, A. M.; Horan, D.; Jordan, M.; Kertzman,
M.; Kieda, D.; Kildea, J.; Knapp, J.; Kosack, K.; Krawczynski, H.;
Krennrich, F.; LeBohec, S.; Linton, E. T.; Lloyd-Evans, J.; Moriarty,
P.; Müller, D.; Nagai, T. N.; Ong, R.; Page, M.; Pallassini, R.;
Petry, D.; Power-Mooney, B.; Quinn, J.; Rebillot, P.; Reynolds,
P. T.; Rose, H. J.; Schroedter, M.; Sembroski, G. H.; Swordy, S. P.;
Vassiliev, V. V.; Wakely, S. P.; Walker, G.; Weekes, T. C.
Bibcode: 2003ApJ...583L...9H
Altcode: 2002astro.ph.12170H
We present the first strong detection of very high energy γ-rays
from the close (z=0.048) X-ray-selected BL Lacertae object 1ES
1959+650. Observations were made with the Whipple 10 m telescope
on Mount Hopkins, Arizona, using the atmospheric Cerenkov imaging
technique. The flux between 2002 May and July was highly variable,
with a mean of 0.64+/-0.03 times the steady flux from the Crab Nebula
and reaching a maximum of 5 crab, with variability on timescales as
short as 7 hr.
Title: The TeV Spectrum of H1426+428
Authors: Petry, D.; Bond, I. H.; Bradbury, S. M.; Buckley, J. H.;
Carter-Lewis, D. A.; Cui, W.; Duke, C.; de la Calle Perez, I.; Falcone,
A.; Fegan, D. J.; Fegan, S. J.; Finley, J. P.; Gaidos, J. A.; Gibbs,
K.; Gammell, S.; Hall, J.; Hall, T. A.; Hillas, A. M.; Holder, J.;
Horan, D.; Jordan, M.; Kertzman, M.; Kieda, D.; Kildea, J.; Knapp,
J.; Kosack, K.; Krennrich, F.; LeBohec, S.; Moriarty, P.; Müller,
D.; Nagai, T. N.; Ong, R.; Page, M.; Pallassini, R.; Power-Mooney, B.;
Quinn, J.; Reay, N. W.; Reynolds, P. T.; Rose, H. J.; Schroedter, M.;
Sembroski, G. H.; Sidwell, R.; Stanton, N.; Swordy, S. P.; Vassiliev,
V. V.; Wakely, S. P.; Walker, G.; Weekes, T. C.
Bibcode: 2002ApJ...580..104P
Altcode: 2002astro.ph..7506P
The BL Lac object H1426+428 was recently detected as a high-energy
γ-ray source by the VERITAS collaboration (Horan et al.). We have
reanalyzed the 2001 portion of the data used in the detection
in order to examine the spectrum of H1426+428 above 250 GeV. We
find that the time-averaged spectrum agrees with a power law
of the shape(dF/dE)(E)=10-7.31+/-0.15stat+/-
0.16systE-3.50+/-0.35stat+/-
0.05systm-2s-1TeV-
1.The statistical evidence from our data for emission above
2.5 TeV is 2.6 σ. At the 95% confidence level, the integral flux
of H1426+428 above 2.5 TeV is larger than 3% of the corresponding
flux from the Crab Nebula. The spectrum is consistent with the
(noncontemporaneous) measurement by Aharonian et al. both in shape
and in normalization. Below 800 GeV, the data clearly favor a spectrum
steeper than that of any other TeV blazar observed so far, indicating
a difference in the processes involved either at the source or in the
intervening space.
Title: Past and future trends in stellar activity cycle research:
beyond Ca II H&K
Authors: Hall, Jeffrey C.
Bibcode: 2002ESASP.508..121H
Altcode: 2002soho...11..121H
Olin C. Wilson began stellar activity cycle research in 1966,
and work has since proceeded along a number of observational and
theoretical lines. Long-term ground-based spectroscopic monitoring
of the Ca II H&K activity proxies has demonstrated the existence
of varying types of stellar cycles, while complementary photometric
studies have revealed luminosity variations both in phase and in
antiphase with chromospheric activity. Beginning in the late 1970s,
space-based observations greatly affected our understanding of stellar
chromospheres, spurring a complementary evolution in interpretation of
the ground-based results. Excellent recent reviews of the results of
these programs have appeared, so in this paper, I will summarize the
results and review them in the broad context of the development of our
present state of knowledge, current outstanding questions and pitfalls
facing workers in the field today, and the lines of investigation
likely to be fruitful in the next decade.
Title: Gauging the Sun: Comparative photometric and magnetic activity
measurements of sunlike stars, 1984-2001
Authors: Lockwood, G. W.; Hall, J. C.; Skiff, B. A.; Henry, G. W.;
Radick, R. R.; Baliunas, S. L.; Soon, W.; Donahue, R. A.
Bibcode: 2002AAS...200.0709L
Altcode: 2002BAAS...34..651L
Visible light photometric observations of a small sample of
sunlike stars with mean chromospheric activity levels similar to or
slightly lower than the Sun's suggest that total solar irradiance
variations on activity cycle timescales may be comparatively small
(Lockwood et al. 1992, Nature 360, 653; Radick et al. 1998, ApJS 118,
239). The Sun's irradiance variation over the past two cycles is
0.04% rms compared with 0.1% rms for the stellar sample measured at
Lowell from 1984 to 1995. This assertion can now be tested using new
photometric measurements from Fairborn Observatory automated telescopes
(1993-2001) that extend the duration of stellar observations to 17
years. Chromospheric activity measurements for these stars come from
the Mount Wilson HK program (1966-2001) and the Lowell Observatory
Solar Stellar Spectrograph program (1993-2001). In this presentation
we will describe efforts to merge the overlapping Lowell and Fairborn
photometry and the Mt. Wilson and Lowell HK measurements with the
goal of reducing the uncertainties in previous efforts to characterize
stellar photometric variations near the limit of detection.
Title: Evidence of a Pronounced Activity Cycle in the Solar Twin
18 Scorpii
Authors: Hall, Jeffrey C.; Lockwood, G. W.
Bibcode: 2000ApJ...545L..43H
Altcode:
The star 18 Scorpii (HD 146233, HR 6060) is currently regarded
as the nearest solar twin. We have been observing this star on
our solar-stellar spectrograph program since 1995. In this Letter
we present our Ca K observations of 18 Sco through 2000 July. The
data show a pronounced rise that suggests 18 Sco has a well-defined
activity cycle that reached an apparent minimum in 1998 and showed a
rapid rise through the most recent of our year 2000 data. Comparison
with contemporaneous solar data, obtained with the same instrument,
suggests that the activity cycle of 18 Sco may be of greater amplitude
than the Sun's and that its overall chromospheric activity level is
noticeably greater than the Sun's. This excellent solar photometric
twin therefore may be a less perfect spectroscopic twin.
Title: Composite Spectral Indices: A New Method for the Interpretation
of Solar and Stellar Activity
Authors: Hall, Jeffrey C.; Lockwood, G. W.
Bibcode: 2000ApJ...541..436H
Altcode:
Activity in solar-like stars is often characterized by one, or at most a
handful, of proxy spectral indicators such as Ca II H and K or Hα. In
this paper we define and explore composite spectral indices (CSIs),
which are derived from consideration of the simultaneous behavior
of larger sets of related spectral lines. With judiciously defined
CSIs, we can examine the short- and long-term variability in a set of
solar or stellar spectra in a complementary way to the traditional
K index. In this paper we demonstrate this method, using our solar
data series spanning the cycle 22/23 minimum and the initial rise of
cycle 23, from 1994 through 1999, and using initial CSIs chosen to be
sensitive to the presence of sunspots. We find that despite the relative
inactivity of the Sun during the time period in question, analysis of
the CSIs reveals the change in sunspot number through solar minimum in
a well-defined way. Manifestation of this solar property in the CSIs
indicates their utility for study of other physical characteristics
in the same way, as well as for comparison of the Sun's physical
properties and low-level variability to individual solar analogs.
Title: A Survey of Activity in the Solar-Type Stars in M67
Authors: Giampapa, M. S.; Radick, R. R.; Hall, J. C.; Baliunas, S. L.
Bibcode: 2000SPD....3102120G
Altcode: 2000BAAS...32..832G
We present an update on a long-term study of the solar-type stars in
the solar-age and solar-metallicity open cluster, M67. The primary
objective of this program is to gain insight on the possible range of
solar chromospheric activity and the associated, potential long-term
variability of the Sun through the observation of stellar analogs of
the Sun. Spectra in the Ca II H & K line region of over 100 stars
in M67, including 76 `solar-type' stars (with unreddened colors in
the range +0.60 <= B-V <= +0.76) and 21 `solar-twins' (+0.63
<= B-V <= +0.67), were obtained with the 3.5-m WIYN telescope
on Kitt Peak in conjunction with the Hydra multi-fiber positioner
to perform multi-object spectroscopy over a 1 degree field. We find
that the distribution of chromospheric H&K line strengths in
the solar-type stars is broader than the distribution of H&K line
emission recorded in modern observations of the Sun, suggesting that the
potential excursion in the amplitude of the solar cycle is greater than
what we have seen so far in the contemporary record. Approximately 30%
of the solar-type stars in M67 exhibit levels of activity that are
outside the present envelope of solar activity. We interpret this to
mean that the Sun can be in a state of magnetic activity---either
exceptional quiescence similar to the Maunder-minimum episode or
enhanced activity---about 30% of the time. The authors gratefully
acknowledge both the NOAO Telescope Allocation Committee and the
WIYN Queue Program for their support of this investigation. The WIYN
Observatory is a joint facility of the University of Wisconsin-Madison,
Indiana University, Yale University, and the NOAO. The NSO and NOAO are
operated by AURA, Inc., under cooperative agreement with the National
Science Foundation.
Title: Evaluation of Solar Activity in Multiple Spectral Lines,
1994-1998
Authors: Hall, J. C.; Lockwood, G. W.
Bibcode: 1999AAS...19510704H
Altcode: 1999BAAS...31.1531H
We present a method for evaluating solar and stellar activity in
terms of the ensemble behavior of many related spectral lines,
rather than using just the classic chromospheric proxy lines such
as Ca II H&K. Manifestations of solar and stellar activity that
are undetectable in a single spectral line become apparent when many
lines are used in tandem. The resulting activity indices (1) allow us
to examine solar activity with greater precision than would otherwise
be possible and (2) allow us to make meaningful comparisons between
the Sun and individual solar analogs. In this poster, we show how
these indices have reliably tracked solar activity through the Cycle
22/23 minimum. This work is supported by a grant from the National
Science Foundation.
Title: Cycles and Long-Term Variability in Solar-Type Stars
Authors: Giampapa, Mark S.; Radick, Richard R.; Hall, Jeffrey C.;
Baliunas, Sallie L.
Bibcode: 1999noao.prop..226G
Altcode:
We propose a long-term extension of our current WIYN/Hydra program to
study chromospheric activity cycles in the `Suns of M67.' Our results
thus far have revealed that the distribution of activity among the
solar- type stars in M67 is broader than what would be expected from a
comparison with the solar cycle. The next step is to determine whether
our results arise from the cyclic modulation of activity alone or
if the relative amplitudes of cycles in solar-type stars and the Sun
are actually similar and the spread in M67 is due to differences in
the mean level of activity. Only a long-term monitoring program of
regular observations can address these questions. The results of this
program are expected to reveal all the potential modes and amplitudes
of magnetic cycles in sun-like stars and, by inference, in the Sun
itself, with important implications for dynamo models and models of
global climate change.
Title: Fixed-Phase Observations of RS Canum Venaticorum and BY
Draconis Systems
Authors: Hall, Jeffrey C.; Wolovitz, Jeffrey B.
Bibcode: 1998AJ....115.2571H
Altcode:
We present our data set of same-hemisphere, or fixed-phase, observations
of five RS Canum Venaticorum and BY Draconis binaries made with
the Solar-Stellar Spectrograph at Lowell Observatory. The purpose
of this study is to evaluate the level of intrinsic variability in
the components of these systems, and to compare it with variability
arising from rotational modulation and from long-term, activity
cycle-related variability. We obtain fixed-phase observations by
observing tidally locked binaries with near-integral-day periods. The
fixed-phase observations reveal that the intrinsic variability of
the stellar hemispheres is significantly less than the variability
induced by rotational modulation or by long-term, activity-cyclic
evolution, but only when several spectral features are considered in
tandem. Fixed-phase ``flickering'' of the stellar hemispheres is often
apparent at a higher level than the rotational or long-term modulation
in individual activity indicators. Interpretation of rotational or
long-term modulation in active, late-type stars using data that do not
allow quantification of the fixed-phase variability of the stars (i.e.,
data that do not span several rotational periods) is extremely risky.
Title: The Solar Activity Cycle. I. Observations of the End of Cycle
22, 1993 September--1997 February
Authors: Hall, Jeffrey C.; Lockwood, G. W.
Bibcode: 1998ApJ...493..494H
Altcode:
We have monitored the Sun through a large portion of the near-IR,
optical, and near-UV spectrum since late 1993 as part of our long-term
observing program with the Solar-Stellar Spectrograph (SSS) at Lowell
Observatory. In this paper we present our database through early 1997,
which covers the end of solar cycle 22 and the first months of cycle
23. Our goals in this paper are fourfold: (1) to establish the absolute
consistency of our data using an automated, completely objective
reduction protocol, (2) to establish a calibration to physical flux
across the entire SSS spectrum for our solar data, (3) to examine the
record of the main chromospheric activity indicator, Ca II K, in our
data, and (4) to search for the Sun's rotational signal in our data
set, to the end that clear detection of the solar rotation at activity
minimum would bode well for our ability to detect rotational signals
in other, more active stars. Further analysis and modeling of these
solar data will appear in forthcoming papers in this series.
Title: Composite Spectral Indices: a New Method for the Interpretation
of Activity in the Sun and Solar Analogs
Authors: Hall, Jeffrey C.
Bibcode: 1998saco.conf..143H
Altcode:
No abstract at ADS
Title: Solar analogs : characteristics and optimum candidates /edited
by Jeffrey
Authors: Hall, Jeffrey C.
Bibcode: 1998saco.conf.....H
Altcode:
No abstract at ADS
Title: Multiwavelength Activity Profiles of Cool Stars
Authors: Hall, J. C.; Baliunas, S. L.
Bibcode: 1996AAS...189.8108H
Altcode: 1996BAAS...28.1383H
We have constructed detailed observing histories of a large number of
cool stars by combining measurements of magnetic-activity-sensitive
lines in ground-based data and space archival data into what we term
multiwavelength activity profiles (MAPs) of these stars. To construct a
MAP, we first combine the Mt. Wilson Observatory HK project data and the
Lowell Observatory Solar-Stellar Spectrograph (SSS) near-UV to near-IR
data for a given target into absolute-flux-calibrated records of the
star's chromospheric variability. We then add IUE NEWSIPS-processed
spectra and available EUV and X-ray data to produce the final MAP,
which provides a comprehensive picture of the long-term variability
in the target stars from their low chromospheres to their coronae. In
this poster we present representative MAPs for nine stars with large
space-based data sets (HDs 20630, 22049, 35296, 39587, 61421, 72905,
115383, 131156A, and 201091). We first describe how we combine the
various data into a uniformly calibrated MAP, and then examine the
response of different regions of the stellar atmospheres to cyclic,
rotational, and short-term variability.
Title: VizieR Online Data Catalog: Empirical stellar flux scales
(Hall 1996)
Authors: Hall, J. C.
Bibcode: 1996yCat..61080313H
Altcode:
Several studies have appeared in the literature describing methods
for deriving stellar continuum fluxes as simple functions of Johnson
color indices. In previous papers, we have used similar relations to
derive Ca II H & K line core fluxes for dwarf stars on Lowell
Observatory's Solar-Stellar Spectrograph (SSS) program. Our desire
is to present our data, and complementary data from the Mt. Wilson
and National Solar Observatory stellar and solar programs, in terms
of physical fluxes. However, our existing relations break down for
mid-K and later stars and for giant stars, which form an important
element of our target list. In this work I have used a broader range
of spectrophotometry and angular diameters than in our previous work
to derive empirical flux scales for spectral types A to early M,
luminosity classes I to V, and for four color indices, Johnson B-V,
V-R, R-I, and Stromgren b-y. In this paper I describe the methods I
used and present the derived flux scales. I compare the results with
those from earlier studies and present examples of the use of the
flux scales. The data and results are available on the World Wide
Web home page. Access http://www.lowell.edu, select "Lowell staff",
and select the author's home page. (4 data files).
Title: On the Determination of Empirical Stellar Flux Scales
Authors: Hall, Jeffrey C.
Bibcode: 1996PASP..108..313H
Altcode:
Several studies have appeared in the literature describing methods
for deriving stellar continuum fluxes as simple functions of Johnson
color indices. In previous papers, we have used similar relations
to derive Ca II H and K line core fluxes for dwarf stars on Lowell
Observatory's Solar-Stellar Spectrograph (SSS) program. Our desire
is to present our data, and complementary data from the Mt. Wilson
and National Solar Observatory stellar and solar programs, in terms
of physical fluxes. However, our existing relations break down for
mid-K and later stars and for giant stars, which form an important
element of our target list. In this work I have used a broader range
of spectrophotometry and angular diamters than in our previous work to
derive empirical flux scales for spectral types A to early M, luminosity
classes I to V, and for four color indices, Johnson B-V, V-R, R-I,
and Stromgren b-y. In this paper, I describe the methods I used and
present the desired flux scales. I compare the results with those from
earlier studies and present examples of the use of the flux scales. The
data and results are available on the World Wide Web. (SECTION: Stars)
Title: Cross-correlation radial velocity measurements of
chromospherically active binaries.
Authors: Gunn, A. G.; Hall, J. C.; Lockwood, G. W.; Doyle, J. G.
Bibcode: 1996A&A...305..146G
Altcode:
We present observational radial velocity curves for 12 chromospherically
active binary systems and individual measurements for a further
5 systems. These binaries are LX Per, V 471 Tau, EI Eri, OU Gem,
GK Hya, TY Pyx, Z Her, MM Her, V772 Her, ER Vul, BD-004234, MY Cyg,
AR Lac, KZ And, RT And, SZ Psc and EZ Peg. Six of our target binaries
do not agree with published ephemerides or orbital parameters. We also
present a rigorous derivation of the resolution limit for binary star
cross-correlation radial velocities. Using synthetic spectral data we
investigate the errors induced by rotational broadening, signal-to-noise
ratio, spectral-type mismatch and luminosity ratio.
Title: Activity Cycles in Cool Stars. I. Observation and Analysis
Methods and Case Studies of Four Well-observed Examples
Authors: Hall, Jeffrey C.; Lockwood, G. W.; Gibb, Erika L.
Bibcode: 1995ApJ...442..778H
Altcode:
This is the first in a series of papers devoted to the ongoing
long-term monitoring program of activity cycles in cool stars at Lowell
Observatory. In this paper we discuss the various spectral diagnostics
we have at our disposal and how we calibrate these diagnostics to
flux. We then present our current database for four well-studied stars,
HD 10700, HD 22049, HD 39587, and the Sun, comparing our results to
results obtained by other investigators and discussing how our new
database complements existing work. With the same data we demonstrate
our ability to detect activity cycles and rotational modulation in
a variety of diagnostic lines for stars of widely differing activity
levels and spectral types.
Title: The Solar-Stellar Spectrograph: Project Description, Data
Calibration, and Initial Results
Authors: Hall, Jeffrey C.; Lockwood, G. W.
Bibcode: 1995ApJ...438..404H
Altcode:
The Solar-Stellar Spectrograph (SSS) is a project initiated in
the 1980s by scientists from the High Altitude Observatory, Lowell
Observatory, the Pennsylvania State Universty, and the Sacramento Peak
Observatory. The instrument is comprised of two spectrographs: one
is an echelle covering the wavelength range lambda lambda 5000-9200,
while the second is a Littrow spectrograph covering the Ca II and H
and K region around lambda 3950. This project is designed to address a
broad range of outstanding questions regarding the nature of stellar
activity cycles. The unique capability of the spectrograph is its
ability to record both solar and stellar spectra, allowing more
accurate placement of the Sun in the stellar context than has been
feasible previously. In this report we discuss the motivation for this
project, the instrumental characteristics, the observing programs, the
methods being used to reduce, calibrate, and analyze the data, and the
connection of our databases to extant databases. A central part of the
discussion is the connection of the Sun with the stars both in terms
of existing solar and stellar activity indices as well as physical
flux. This work resolves a long-standing discrepancy in this area and
establishes a protocol for relating the large set of observations from
the Mount Wilson Ca II H and K project to physical flux, in preparation
for future comparison to our observations and results from theory.
Title: The Solar-Stellar Spectrograph: Unification of Solar and
Stellar Flux Scales and Initial Results
Authors: Hall, Jeffrey C.; Lockwood, G. W.; Gibb, Erika L.
Bibcode: 1994AAS...185.8017H
Altcode: 1994BAAS...26Q1449H
We present the science results from the first two years of the
Solar-Stellar Spectrograph (SSS) project. These results will include (1)
representative observations from our current database of ~ 1500 spectra
of about 200 solarlike stars, (2) a discussion of their calibration
to flux, (3) our initial detections of cyclic as well as shorter-term
variability, (4) variability correlations between various diagnostic
lines, (5) the unification of our flux-calibrated data to all extant
datasets, in particular the Mt. Wilson S index, and (6) the consistent
placement of the Sun among the stellar sample.
Title: The Solar-Stellar Spectrograph: The Sun in 1994
Authors: Lockwood, G. W.; Hall, Jeffrey C.; Gibb, Erika L.
Bibcode: 1994AAS...185.8016L
Altcode: 1994BAAS...26.1449L
We present Ca II HK and IRT and Hα observations of the end of
solar cycle 22 in 1994. We discuss the calibration of these activity
diagnostics to flux and compare the results with similarly determined
fluxes from stellar analogs of the Sun. We reconcile these data with
the long-term NSO datasets and with the Mt. Wilson S index of stellar
activity, establishing a spectroscopic context for accurate placement
of the Sun among the stars.
Title: Multiwavelength Study of the Magnetically Active T Tauri Star
HD 283447
Authors: Feigelson, Eric D.; Welty, Alan D.; Imhoff, Catherine; Hall,
Jeffrey C.; Etzel, Paul B.; Phillips, Robert B.; Lonsdale, Colin J.
Bibcode: 1994ApJ...432..373F
Altcode:
We observed the luminous T Tauri star HD 283447 = V773 Tauri
simultaneously at X-ray, ultraviolet, optical photometric and
spectroscopic, and radio wavelengths for several hours on UT
1992 September 11. ROSAT, IUE, Very Large Array (VLA) and an
intercontinental Very Long Baseline Interferometry (VLBI) network,
and three optical observatories participated in the campaign. The
star is known for its unusually high and variable nonthermal radio
continuum emission. High levels of soft X-ray and Mg II line emission
are discovered, with luminosity Lx = 5.5 x 1030
ergs/s (0.2 - 2 keV) and LMg II = 1 x 1029
ergs/s, respectively. Optically, the spectrum exhibits rather
weak characteristics of `classical' T Tauri stars. A faint, broad
emission line component, probably due to a collimated wind or infall,
is present. During the campaign, the radio luminosity decreased by a
factor of 4, while optical/UV lines and X-ray emission remained strong
but constant. The large gyrosynchrotron-emitting regions are therefore
decoupled from the chromospheric and coronal emission. Five models
for the magnetic geometry around the star are discussed; solar-type
activity, dipole magnetosphere, star-disk magnetic coupling, disk
magnetic fields, and close binary interaction. The data suggest
that two magnetic geometries are simultaneously present: complex
multipolar fields like those on the Sun, and a large-scale field
possibly associated with the circumstellar disk.
Title: Eclipse Observations of RS CVN Binaries II. A Parametric
Model of Extended Matter
Authors: Hall, Jeffrey C.; Ramsey, Lawrence W.
Bibcode: 1994AJ....107.1149H
Altcode:
We have surveyed ten RS CVn binary systems and have detected large
regions of extended, prominencelike material which we have shown to be
a common feature in these systems. These extended regions are apparent
as anomalous absorption features in the spectra when they obscure the
disk of the eclipsed star and as weak emission features when they
appear with no disk behind. We have constructed a first-generation
model to verify the general prominencelike nature of the material and to
estimate its extent and its most basic physical characteristics. In this
paper we present our results of our modeling on four of the systems in
our survey that showed clear signatures of extended material: AW Her,
MM Her, SS Boo, and UV Psc. We find that these stellar prominencelike
structures are very much larger than their solar counterparts, though
their gross physical characteristics (i.e., their electron density
and temperature and their general appearance as tenuous, vertically
oriented, magnetically confined structures) are similar to those seen
in solar prominences. These features appear to evolve fairly rapidly,
since moderate- to high-velocity flows ranging from several tens of
km/s to 170 km/s are apparent. However, in at least one case (SS Boo)
they are recurrent over a time scale of at least a year. We conclude
by discussing the implications of this work regarding the nature of
close binary star active structures and their evolution.
Title: The Reduction of Fiber-Fed Echelle Spectrograph Data: Methods
and an IDL-Based Solution Procedure
Authors: Hall, Jeffrey C.; Fulton, Eliza E.; Huenemoerder, David P.;
Welty, Alan D.; Neff, James E.
Bibcode: 1994PASP..106..315H
Altcode:
Echelle spectrograph data present several challenges in data
reduction. In this paper we address the general problem of accurately
extracting spectra from a night's worth of raw CCD fiber-fed echelle
data frames. We first briefly review echelle spectroscopy: properties
of the basic echelle spectrograph, how the orders are arranged on
the CCD, and what demands and constraints this data format places
on reduction algorithms. We then discuss solutions to the various
problems for fiber-fed data, with particular emphasison the removal of
the scattered light background. Finally, we discuss our implementation
of these solutions. We have written a package using the Interactive
Data Language (IDL) that uses the methods described in this paper to
give accurate extractions of spectra from fiber-fed echelle frames
with any number of spectral orders of arbitrary tilt and curvature. We
describe how interested persons may obtain the package through anonymous
FTP. (SECTION: Instrumentation and Data Analysis)
Title: Evidence for physically distinct source regions for Balmer
and Ca II excess emission in RS CVn binaries.
Authors: Chester, M. M.; Hall, J. C.; Buzasi, D. L.
Bibcode: 1994ASPC...64..390C
Altcode: 1994ASPC...64..390M; 1994csss....8..390C
Quantitative statistical comparisons of Balmer and Ca II infrared
triplet excess emission diagnostics for solar plages and five active RS
CVn binaries are discussed. Models of Balmer line emission by Buzasi
and the study of eclipsing systems by Hall and Ramsey previously
demonstrated the presence of significant amounts of extended,
prominence-like material in RS CVns. In contrast to the Balmer
emission, the Ca II infrared triplet appears to arise predominantly
in chromospheric plage. The RS CVns are not simply scaled-up solar
active regions.
Title: Multiwavelength Campaign of the Magnetically Active T Tauri
Star HD 283447
Authors: Feigelson, Eric D.; Welty, Alan D.; Imhoff, Catherine L.;
Hall, Jeffrey C.; Etzel, Paul B.; Deeney, Bryan D.; Phillips, Robert
B.; Lonsdale, Colin J.
Bibcode: 1994ASPC...64..405F
Altcode: 1994csss....8..405F
No abstract at ADS
Title: A reduction package for cross-dispersed echelle spectrograph
data in IDL
Authors: Hall, Jeffrey C.; Neff, James E.
Bibcode: 1992AAS...181.1301H
Altcode: 1992BAAS...24R1139H
We have written in IDL a data reduction package that performs reduction
and extraction of cross-dispersed echelle spectrograph data. The
present package includes a complete set of tools for extracting
data from any number of spectral orders with arbitrary tilt and
curvature. Essential elements include debiasing and flatfielding
of the raw CCD image, removal of scattered light background, either
nonoptimal or optimal extraction of data, and wavelength calibration
and continuum normalization of the extracted orders. A growing set of
support routines permits examination of the frame being processed to
provide continuing checks on the statistical properties of the data
and on the accuracy of the extraction. We will display some sample
reductions and discuss the algorithms used. The inherent simplicity and
user-friendliness of the IDL interface make this package a useful tool
for spectroscopists. We will provide an email distribution list for
those interested in receiving the package, and further documentation
will be distributed at the meeting.
Title: A reduction package for cross-dispersed echelle spectrograph
data in IDL.
Authors: Hall, J. C.; Neff, J. E.
Bibcode: 1992BAAS...24Q1139H
Altcode:
No abstract at ADS
Title: Eclipse Observations of RS CVn Binaries. I. A Survey for
Extended Matter
Authors: Hall, Jeffrey C.; Ramsey, Lawrence W.
Bibcode: 1992AJ....104.1942H
Altcode:
We survey a number of RS CVn systems to determine the frequency and
nature of circumstellar matter in these chromospherically active
binaries. A growing body of data suggests that large extended regions
of cool, prominence-like matter may be a common phenomenon in these
systems. Our targets are eclipsing systems as the established geometries
and occultations are useful probes for such extended material. In this
paper we discuss our methods and present the results of our survey and
our spectroscopic phase monitoring of these systems. We find extended
material in eight of the ten systems on our present survey.
Title: Optical Spectroscopy of Chromospherically Active Binary
Systems in Conjunction with the ROSAT All-Sky Survey
Authors: Welty, A. D.; Hall, J. C.; Patterer, R. J.; Ramsey, L. W.;
Huenemoerder, D. P.
Bibcode: 1992ASPC...26..116W
Altcode: 1992csss....7..116W
No abstract at ADS
Title: A Study of Extended Matter in RS CVn Systems
Authors: Hall, J. C.; Ramsey, L. W.
Bibcode: 1992ASPC...26..359H
Altcode: 1992csss....7..359H
No abstract at ADS
Title: A Spectroscopic Analysis of Extended Matter in Eclipsing RS
CVN Binaries.
Authors: Hall, Jeffrey Clifton
Bibcode: 1991PhDT........73H
Altcode:
I have conducted a survey of a number of eclipsing RS CVn binaries
to search for the presence of extended matter associated with the
component stars. Previous evidence indicates that this extended
matter is more like solar quiescent prominences than other structures
such as plage; as such, it is most identifiable when viewed off the
stellar limb. In eclipsing systems, the matter can be seen indirectly
as it obscures a portion of the eclipsed star's limb. My survey has
identified some systems in which this is the case. Parameterization of
the physical extent of the extended matter is a geometrical problem
wherein the amount of obscuration caused by the prominence depends
on its size and orientation as well as its optical depth in the
line of interest. I have done this using a Simplex algorithm which
I have developed and specifically tailored to the problem at hand. I
classify the extended components I have seen and discuss their effect
on the spectral profiles. Other spectral diagnostics provide clues
as to their origin, and I discuss this in the context of the present
"solar analogy" paradigm.
Title: Fixed Phase Observations of RS CVn Stars
Authors: Hall, J. C.; Huenemoerder, D. P.; Ramsey, L. W.; Patterer,
R. J.; Chester, M. M.
Bibcode: 1990BAAS...22.1292H
Altcode:
No abstract at ADS
Title: Fiber-optic Echelle CCD Observations of SS Bootis
Authors: Hall, Jeffrey C.; Huenemoerder, David P.; Ramsey, Lawrence
W.; Buzasi, Derek L.
Bibcode: 1990ApJ...358..610H
Altcode:
The faint RS CVn system SS Bootis was observed over two seasons, and the
most prominent surface activity indicators in this spectroscopically
understudied object were examined. The first two Balmer lines are
consistently strong in emission, as are the Ca II infrared triplet and
Ca II H line; there is no significant modulation with phase in any of
these lines. No excess emission is evident in He I D3. The ratio of
energy emitted in H-alpha to that in H-beta is typically between three
and six for the more active subgiant primary, and between two and five
for the dwarf secondary. Of special interest is an excess absorption
feature in the Balmer lines near primary eclipse in both seasons. The
feature lies near the velocity of the secondary, and as there is no
similar feature in secondary eclipse, it is suggested that it arises
from obscuring material associated with the primary. From the extent
of the feature and the system's geometry, limits were placed on the
parameters of such material.
Title: Evidence for Extended Material in the Eclipsing RS CVn System
SS Bootis
Authors: Hall, J. C.; Huenemoerder, D. P.; Ramsey, L. W.; Buzasi, D. L.
Bibcode: 1990BAAS...22..739H
Altcode:
No abstract at ADS
Title: Tests of a Multi-site Scintillation Gamma-Ray Detector
Authors: Hall, J. C.; Agrinier, B.; Dean, J. A.; Labanti, C.
Bibcode: 1990ICRC....4..171H
Altcode: 1989ICRC....4..171H; 1990ICRC...21d.171H
No abstract at ADS
Title: MAVIS?an upper crustal seismic refraction experiment in the
Midland Valley of Scotland
Authors: Dentith, M. C.; Hall, J.
Bibcode: 1989GeoJI..99..627D
Altcode:
No abstract at ADS
Title: Superluminal Motion toward a Stationary Knot in the Radio
Core of the Quasar 3C 395
Authors: Simon, R. S.; Hall, J.; Johnston, K. J.; Spencer, J. H.;
Waak, J. A.; Mutel, R. L.
Bibcode: 1988ApJ...326L...5S
Altcode:
We have recently confirmed that the quasar 3C 395 (1901+319) is a
superluminal radio source, based upon one 18 cm and three 6 cm VLBI
images of the compact radio emission in 3C 395 obtained over a 5.5
yr period. The compact structure in 3C 395 (at 6 cm with a convolving
beam of 2.4 x 1.8 mas, position angle 162^deg^) is dominated by three
components: (1) A bright, unresolved component to the northwest, almost
certainly the central core of 3C 395. It has apparently brightened
by about 0.4 Jy between 1983.3 and 1985.4, from 0.6 Jy to 1.0 Jy. (2)
A moderately resolved component 15.8+/-0.2 mas to the southeast along
position angle 118^deg^. The position of this component relative to
the core has changed by less than 0.2 mas in 6 yr. The flux density of
this component has remained nearly constant over the past 6 yr. (3)
A component whose flux density has remained constant between 1983.3
and 1985.4 moving rapidly away from the core toward component 2 with
a proper motion of 0.64+/-0.1 mas per year. At the distance of 3C 395
(z = 0.635), this corresponds to an apparent velocity of ~15h^-1^ c
for H_0_ = 100h km s^-1^ Mpc^-1^ and q_0_ = 0.05. The object 3C 395 is
unique among the dozen or so superluminals, in that on milliarcsecond
scales it has a superluminal component moving between two relatively
stationary components.
Title: Superluminal motion towards a stationary component in quasar
3C 395.
Authors: Simon, R. S.; Johnston, K. J.; Hall, J.; Spencer, J. H.;
Waak, J. A.
Bibcode: 1987slrs.work...72S
Altcode:
3C395 has been observed to be unique among superluminals in that it
has a superluminal component moving between two relatively stationary
components. In this paper, VLBI observations at 6 cm are reported which
confirm the three-component structure and the superluminal motion of the
middle component. A speculative interpretation of the object is offered
in which 3C395 is a core-jet radio source in which the jet, originating
nearly along the line of sight, bends back through the line of sight.
Title: Superluminal Motion in the Quasar 3C 395
Authors: Simon, R. S.; Hall, J.; Johnston, K. J.; Spencer, J. H.;
Waak, J. A.
Bibcode: 1986BAAS...18..993S
Altcode:
No abstract at ADS
Title: Stabilized Lasers
Authors: Baer, T.; Hall, J.
Bibcode: 1981siwn.conf..142B
Altcode:
No abstract at ADS
Title: Vp measurements on crustal xenoliths from San Juan
County Utah
Authors: Padovani, E. R.; Hall, J.; Simmons, G.
Bibcode: 1978LPICo.329...34P
Altcode:
No abstract at ADS
Title: Shift and Broadening of Saturated Absorption Resonances Due
to Curvature of the Laser Wavefronts
Authors: Hall, J.; Borde, C.
Bibcode: 1976sfsm.conf..115H
Altcode:
No abstract at ADS
Title: Direct Optical Resolution of the Recoil Effect Using Saturated
Absorption Spectroscopy
Authors: Hall, J.; Borde, C.
Bibcode: 1976sfsm.conf..125H
Altcode:
No abstract at ADS
Title: Discussion of the relation of palaeogene ridge and basin
structures of Britain to the North Atlantic
Authors: Hall, J.; Smythe, D. K.
Bibcode: 1973E&PSL..19...54H
Altcode:
The evidence of Tertiary ridges, basins and volcanicity in Britain is
at variance with a simple relation to the Atlantic opening as proposed
recently by Hallam. The structural complexity of the continental margin
off Britain needs further investigation before its development can be
related satisfactorily to the several phases of opening of the North
Atlantic. In particular, Mesozoic and Tertiary basins and ridges
do not consistently show the elongation and asymmetry required by
Hallam's model, and many were initiated too early to be related to
the Reykjanes spreading.