Author name code: korzennik ADS astronomy entries on 2022-09-14 author:"Korzennik, Sylvain" ------------------------------------------------------------------------ Title: Helioseismic Constraints on the Solar Interior Dynamics and Dynamo Authors: Kosovichev, A. G.; Brummell, N.; Dikpati, M.; Guerrero, G.; Kitiashvili, I.; Komm, R.; Korzennik, S.; Pipin, V.; Reiter, J.; Stejko, A.; Ulrich, R. K.; Warnecke, J. Bibcode: 2020AGUFMSH007..04K Altcode: Uninterrupted helioseismic observations from the SoHO/MDI, SDO/HMI and GONG instruments for more than two decades provide unique observational data for studying the solar-cycle variations of the differential rotation, large-scale and meridional flows. The data also allows us to investigate changes in the thermodynamic structure associated with dynamo-generated magnetic fields. The wealth of global and local helioseismic data provides theoretical constraints on the solar dynamics and dynamo models. The synergy of helioseismic inferences with advanced MHD modeling sheds light on the origin of the solar activity cycles. It helps to understand better the physical processes that control the strength and duration of the cyclic magnetic activity and leads to new physics-based approaches for prediction of the solar cycles. We briefly overview the current status, discuss the solar dynamical structure and evolution revealed by helioseismic inversions and the forward-modeling method, and focus on the most critical points of the problem. In particular, we discuss recent advances in measurements and modeling of the solar-cycle variations of the meridional circulation and migrating zonal flows (torsional oscillations) on the solar surface and in the subsurface layers, the deep convection zone, and the solar tachocline. The relationships between the internal dynamics and the evolution of global magnetic fields lead to new ideas of how magnetic fields are generated and affect the solar flows and structure. Title: On Active Region Emergence Precursors Authors: Korzennik, Sylvain G. Bibcode: 2020ASSP...57..129K Altcode: I present intriguing results from a systematic look at possible indicators of active region emergence precursors using both acoustic power mapping and time distance travel time anomalies. I analyzed a set of active regions that have emerged at low latitudes and close to the central meridian, and were observed with HMI. Such regions, since they emerged near disk center, could be tracked for days before and after their emergence. Data cubes of tracked surface observable were analyzed, using time-series of various length, using HMI's intensity, velocity and magnetic field data. While each active region displays its own particularities, this systematic approach allowed me to pick some interesting statistical properties that will be summarized. Using different time-series length allowed me to investigate the trade-off between precision and resolution, whether temporal or spatial. It also revealed to which extent one sees a tight correlation between various metric of surface activity and its effect of the measured acoustic signal, whether seen in raw of filtered power map or travel time anomalies. Title: On the search of active region emergence precursors using acoustic power maps and travel time anomalies derived from time-distance analysis of HMI observations Authors: Korzennik, Sylvain G. Bibcode: 2019AAS...23430505K Altcode: I present initial results from a systematic look at possible indicators of active region emergence precursors using acoustic power mapping and time distance travel time anomalies. Using HMI observations I have analyzed a set of active regions that have emerged at low latitudes and close to the central meridian. Since these regions emerged close to disk center, they could be tracked for days before and after their emergence. Data cubes of tracked surface images of various lengths were analyzed using both intensity and velocity observations. While each active region exhibits particular properties, this systematic approach allowed me to look at a few statistical properties that will be summarized. Namely the trade-off between precision and resolution, both temporal and spatial resolution, and the correlation between various metric of surface activity and its impact of the measured acoustic signal, whether seen in power map (filtered or not) or travel time anomalies derived from a time-distance analysis (also using a few different filtering). Title: New and Improved Mode Fitting Results Authors: Korzennik, Sylvain G. Bibcode: 2018csc..confE.132K Altcode: I present the most recent improvements to my mode fitting procedures, and how they affect inferred properties of the Sun. The fitting has now been extended to ℓ=0 modes, and in the process to more ℓ=1 modes. Close scrutiny of these low degree modes revealed the need to change the scaling of the error bars on the derived multiplet quantities. I fitted a test data set using different leakage matrices, including one set computed to fit very long time series and therefore uses for B_o the value of 5.0593^o (or √{|Bo^2|}). I show how that leakage matrix is different from the one computed in the past for very long time series (B_o=0) and its impact on the fitted parameters. Title: Initial Results from Fitting p -Modes Using Intensity Observations from the Helioseismic and Magnetic Imager Authors: Korzennik, Sylvain G. Bibcode: 2017SoPh..292..138K Altcode: The Helioseismic and Magnetic Imager project recently started processing the continuum-intensity images following global helioseismology procedures similar to those used to process the velocity images. The spatial decomposition of these images has produced time series of spherical harmonic coefficients for degrees up to ℓ =300 , using a different apodization than the one used for velocity observations. The first 360 days of observations were processed and are made available. I present initial results from fitting these time series using my fitting method and compare the derived mode characteristics to those estimated using coeval velocity observations. Title: Detailed Image Comparison using MDI, HMI and GONG Co-Eval Observations Authors: Korzennik, Sylvain G. Bibcode: 2017SPD....4811302K Altcode: I present preliminary results from detailed image comparison using MDI, HMI and GONG co-eval observations taken in 2014, when all three instruments were operational. This comparison allows me to estimate both the instrumental image distortion and the instrument PSF, with respect to HMI. Both intensity and velocity images are compared when available. The precise observing perspective of each instrument had to be accounted since it affects the projected image on the instrument detector at the required level of precision (i.e., a fraction of an HMI pixel). In the process, it was discovered that the meta data generated by the respective projects were not accurate enough. While the inclusion of the image distortion and the instrument PSF in the spatial decomposition will improve the determination of high degree modes, it may also benefit other local helioseismic analysis. Title: Initial Results from Fitting Resolved Modes using HMI Intensity Observations Authors: Korzennik, Sylvain G. Bibcode: 2017SPD....4811301K Altcode: The HMI project recently started processing the continuum intensity images following global helioseismology procedures similar to those used to process the velocity images. The spatial decomposition of these images has produced time series of spherical harmonic coefficients for degrees up to l=300, using a different apodization than the one used for velocity observations. The first 360 days of observations were processed and made available. I present initial results from fitting these time series using my state of the art fitting methodology and compare the derived mode characteristics to those estimated using co-eval velocity observations. Title: Initial Results from Fitting Resolved Modes using HMI Intensity Observations Authors: Korzennik, Sylvain G. Bibcode: 2017arXiv170709895K Altcode: The HMI project recently started processing the continuum intensity images following global helioseismology procedures similar to those used to process the velocity images. The spatial decomposition of these images has produced time series of spherical harmonic coefficients for degrees up to $\ell=300$, using a different apodization than the one used for velocity observations. The first 360 days of observations were processed and made available. In this paper I present initial results from fitting these time series using my state of the art fitting methodology and compare the derived mode characteristics to those estimated using co-eval velocity observations. Title: Temporal Changes of pModes Properties Derived from Nearly 20 Year of Observations Authors: Korzennik, Sylvain G. Bibcode: 2016usc..confE.125K Altcode: I present a detailed comparison of the temporal changes of the characteristics of the low and intermediate p-modes oscillations derived from nearly 20 years of observations acquired from three instruments: GONG, MDI and HMI. These characteristics were estimated using three quite different data reduction pipe-lines. The comparisons are both at the level of mode characteristics (frequency, linewidth, amplitude and asymmetry) and at the level of inferred properties of the solar interior (i.e., changes in the solar internal rotation), and for co-eval observations. Title: On the Temporal Changes of Helioseismic Properties Derived with Different Techniques Authors: Korzennik, Sylvain G. Bibcode: 2016SPD....4710701K Altcode: I present a detailed comparison of the temporal changes of the characteristics of the low and intermediate p-modes oscillations derived from nearly 20 years of observations acquired from three instruments (GONG, MDI and HMI) and computed using three quite different data reduction pipe-lines. The comparisons are both at the level of mode characteristics (frequency, linewidth, amplitude and asymmetry) and at the level of inferred properties of the solar interior (i.e., changes in the solar internal rotation). Title: Fitting medium and high degrees using GONG, MDI and HMI observations. Authors: Korzennik, Sylvain G. Bibcode: 2014AAS...22421813K Altcode: I present results from fitting data from the three major helioseismic instruments: GONG, MDI, and HMI, both at medium degree (resolved modes) and at high degrees (ridge fitting). The medium-l fitting was carried out on time-series of varying lengths (1x, 2x, 4x, 8x, 16x, 32x, 64x 72 day longs, and 36 day long ones), the high-l fitting was carried out on co-eval time-series that correspond to the 2001, 2002 and 2010 MDI Dynamics runs. I present these results, compare them and discuss the potential sources of the discrepancies. Title: Mode Frequencies from GONG, MDI, and HMI Data Authors: Korzennik, S. G. Bibcode: 2013ASPC..478..137K Altcode: I present recent results from fitting all the available data from the three major helioseismic instruments: GONG, MDI and HMI using my independent methodology. This method not only fits individual singlets, but: fits them simultaneously for a given multiplet; uses an optimal multi-taper spectral estimator; includes the full leakage matrix and the effect of mode distortion by differential rotation; and fits an asymmetric mode profile. The mode fitting was carried out on time series of varying lengths (1×, 2×, 4×, 8×, 16×, 32×, 64× 72 days long), using co-eval epochs for all three instruments. By fitting time series of varying lengths, one trades off some temporal resolution for a better precision. I present these results, compare them and discuss the potential sources of the discrepancies. Title: Characterization of High-Degree Modes using MDI, HMI and GONG Data Authors: Korzennik, S. G.; Eff-Darwich, A.; Larson, T. P.; Rabello-Soares, M. C.; Schou, J. Bibcode: 2013ASPC..478..173K Altcode: We present the first characterization of high-degree modes (i.e., ℓ up to 900 or 1000), using three instruments and three epochs corresponding to the 2001, 2002 and 2010 MDI Dynamics runs. For 2001, we analyzed MDI full-disk Dopplergrams, while for 2002, we analyzed MDI and GONG full-disk Dopplergrams, and for 2012 we analyzed MDI, GONG and HMI full-disk Dopplergrams. These Dopplergrams were spatially decomposed up to ℓ = 900 or 1000, and power spectra for all degrees and all azimuthal orders were computed using a high-order multi-taper, power spectrum estimator. These spectra were then fitted for all degrees and all azimuthal orders, above ℓ = 100, and for all orders with substantial amplitude. Fitting at high degrees generates ridge characteristics, characteristics that do not correspond to the underlying mode characteristics. We used a sophisticated forward modeling to recover the best possible estimate of the underlying mode characteristics (mode frequencies, as well as linewidths, amplitudes and asymmetries). We present the first attempt to apply this method to three instruments and three epochs. The derived sets of corrected mode characteristics (frequencies, line widths, asymmetries and amplitudes) are presented and compared. Title: The Dynamics of the Solar Radiative Zone Authors: Eff-Darwich, A.; Korzennik, S. G. Bibcode: 2013SoPh..287...43E Altcode: 2012arXiv1205.3143E; 2012SoPh..tmp..149E The dynamics of the solar radiative interior are still poorly constrained by comparison to the convective zone. This disparity is even more marked when we attempt to derive meaningful temporal variations. Many data sets contain a small number of modes that are sensitive to the inner layers of the Sun, but we found that the estimates of their uncertainties are often inaccurate. As a result, these data sets allow us to obtain, at best, a low-resolution estimate of the solar-core rotation rate down to approximately 0.2R⊙. We present inferences based on mode determination resulting from an alternate peak-fitting methodology aimed at increasing the amount of observed modes that are sensitive to the radiative zone, while special care was taken in the determination of their uncertainties. This methodology has been applied to MDI and GONG data, for the whole Solar Cycle 23, and to the newly available HMI data. The numerical inversions of all these data sets result in the best inferences to date of the rotation in the radiative region. These results and the method used to obtain them are discussed. The resulting profiles are shown and analyzed, and the significance of the detected changes is discussed. Title: Accurate Characterization of High-degree Modes Using MDI Observations Authors: Korzennik, S. G.; Rabello-Soares, M. C.; Schou, J.; Larson, T. P. Bibcode: 2013ApJ...772...87K Altcode: We present the first accurate characterization of high-degree modes, derived using the best Michelson Doppler Imager (MDI) full-disk full-resolution data set available. A 90 day long time series of full-disk 2 arcsec pixel-1 resolution Dopplergrams was acquired in 2001, thanks to the high rate telemetry provided by the Deep Space Network. These Dopplergrams were spatially decomposed using our best estimate of the image scale and the known components of MDI's image distortion. A multi-taper power spectrum estimator was used to generate power spectra for all degrees and all azimuthal orders, up to l = 1000. We used a large number of tapers to reduce the realization noise, since at high degrees the individual modes blend into ridges and thus there is no reason to preserve a high spectral resolution. These power spectra were fitted for all degrees and all azimuthal orders, between l = 100 and l = 1000, and for all the orders with substantial amplitude. This fitting generated in excess of 5.2 × 106 individual estimates of ridge frequencies, line widths, amplitudes, and asymmetries (singlets), corresponding to some 5700 multiplets (l, n). Fitting at high degrees generates ridge characteristics, characteristics that do not correspond to the underlying mode characteristics. We used a sophisticated forward modeling to recover the best possible estimate of the underlying mode characteristics (mode frequencies, as well as line widths, amplitudes, and asymmetries). We describe in detail this modeling and its validation. The modeling has been extensively reviewed and refined, by including an iterative process to improve its input parameters to better match the observations. Also, the contribution of the leakage matrix on the accuracy of the procedure has been carefully assessed. We present the derived set of corrected mode characteristics, which includes not only frequencies, but line widths, asymmetries, and amplitudes. We present and discuss their uncertainties and the precision of the ridge-to-mode correction schemes, through a detailed assessment of the sensitivity of the model to its input set. The precision of the ridge-to-mode correction is indicative of any possible residual systematic biases in the inferred mode characteristics. In our conclusions, we address how to further improve these estimates, and the implications for other data sets, like GONG+ and HMI. Title: Mode Frequencies from 17, 15 and 2 Years of GONG, MDI, and HMI Data Authors: Korzennik, S. G.; Eff-Darwich, A. Bibcode: 2013JPhCS.440a2015K Altcode: We present results from fitting all the available data to date from the three major helioseismic instruments: MDI, GONG and HMI. These data were fitted using an innovative and independent methodology devised a few years ago. The mode fitting was carried out on time series of varying lengths (1×, 2×, 4×, 8×, 16×, 32×, 64 × 72 day-long), using co-eval epochs for all three data sets. By fitting time series of varying lengths, one trades off some temporal resolution for a better precision. We present a comparison of these results, and discuss the potential sources of the residual small discrepancies. We also present inferences from these results on the determination of the solar internal rotation and changes with epoch and thus activity levels. Title: Accurate characterization of high-degree modes using MDI data Authors: Korzennik, S. G.; Rabello-Soares, M. C.; Schou, J.; Larson, T. Bibcode: 2013JPhCS.440a2016K Altcode: 2012arXiv1209.6414K We present the first accurate characterization of high-degree modes (i.e., l up to 1000), using the best MDI full-disk full-resolution data set available (90-day long time series, acquired in 2001). The Dopplergrams were spatially decomposed using our best estimate of the image scale and the known components of MDI's image distortion. Multi-tapered power spectra were fitted for all degrees and all azimuthal orders, between l = 100 and l = 1000, and for all orders with substantial amplitude. Fitting at high degrees generates ridge characteristics, characteristics that do not correspond to the underlying mode characteristics. We used a sophisticated forward modeling to recover the best possible estimate of the underlying mode characteristics. We have derived a final set of corrected mode characteristics (frequencies, line widths, asymmetries and amplitudes) and their uncertainties. Title: Erratum: "On the Determination of Michelson Doppler Imager High-degree Mode Frequencies" (2004, ApJ, 602, 481) Authors: Korzennik, S. G.; Rabello-Soares, M. C.; Schou, J. Bibcode: 2012ApJ...760..156K Altcode: No abstract at ADS Title: A Determination of High-degree Mode Parameters Based on MDI Observations Authors: Korzennik, S. G.; Rabello-Soares, M. C.; Schou, J.; Larson, T. P. Bibcode: 2012ASPC..462..189K Altcode: We present the best to date determination of high-degree mode parameters obtained from a ninety day long time series of full-disk full-resolution Michelson Doppler Imager (MDI) Dopplergrams. These Dopplergrams were decomposed using our best estimate of the image scale and the known components of MDI's image distortion. The spherical harmonic decomposition was carried out up to ℓ=1000, and a high-order sine multi-taper power spectrum estimator was used to generate power spectra. These power spectra were fitted for all degrees and all azimuthal orders, for 100 ≤ ℓ ≤ 1000, and for all radial orders with substantial amplitude, generating some 6 × 106 estimates of ridge frequencies, line-widths, amplitudes and asymmetries. We used a sophisticated forward modeling of the mode to ridge blending, to recover the best possible estimate of the underlying mode characteristics. Title: The Solar Rotation and Its Evolution during Cycle 23 Authors: Korzennik, S. G.; Eff-Darwich, A. Bibcode: 2012ASPC..462..267K Altcode: We present the most exhaustive and accurate inferences of the internal solar rotation rate and its evolution during solar cycle 23. A full solar cycle of Michelson Doppler Imager (MDI) observations has been analyzed using our state of the art fitting methodology. Time series of various lengths have been fitted, from a single 4608-day long epoch (64 × 72 day or 12.6 year) down to 64 separate segments for the traditional 72-day long epochs. We used time series of spherical harmonic coefficients computed by the MDI group but using an improved spatial decomposition. This decomposition now includes our best estimate of the image plate scale and of the MDI instrumental image distortion. The leakage matrix used for the fitting includes the effect of the distortion of the eigenfunctions by the solar differential rotation, and the undistorted leakage matrix was itself carefully reviewed and independently recomputed. Rotation inversions were carried out for all the available mode sets for that epoch and all available segments, including the MDI and Global Oscillation Network Group (GONG) pipe-line sets. The improved inversion method we used is an iterative methodology based on a regularized least-squares. It implements a model grid optimization derived from the actual information in the input set. This optimized model grid is itself irregular, namely with a variable number of latitudes at different depths. We present the most accurate mean rotation rate, to date. We also focus on the change of the rotation rate with activity levels and how well these changes are assessed at high latitudes and below the surface, down to the base of the convection zone. Title: Calibration of an echelle spectrograph with an astro-comb: a laser frequency comb with very high repetition rate Authors: Phillips, David F.; Glenday, Alex; Li, Chih-Hao; Furesz, Gabor; Benedick, Andrew J.; Chang, Guoqing N.; Chen, Li-Jin; Korzennik, Sylvain; Sasselov, Dimitar; Kaertner, Franz X.; Szentgyorgyi, Andrew; Walsworth, Ronald L. Bibcode: 2012SPIE.8446E..8OP Altcode: Searches for extrasolar planets using precision radial velocity (PRV) techniques are approaching Earth-like planet sensitivity, however require an improvement of one order of magnitude to identify earth-mass planets in the habitable zone of sun-like stars. A key limitation is spectrograph calibration. An astro-comb, an octave-spanning laser frequency comb and a Fabry-Pérot cavity, producing evenly spaced frequencies with large wavelength coverage, is a promising tool for improved wavelength calibration. We demonstrate the calibration of a high-resolution astrophysical spectrograph below the 1 m/s level in the 8000-9000 Å and 4200 Å spectral bands. Title: Calibration of an astrophysical spectrograph below 1 m/s using a laser frequency comb Authors: Phillips, David F.; Glenday, Alexander G.; Li, Chih-Hao; Cramer, Claire; Furesz, Gabor; Chang, Guoqing; Benedick, Andrew J.; Chen, Li-Jin; Kärtner, Franz X.; Korzennik, Sylvain; Sasselov, Dimitar; Szentgyorgyi, Andrew; Walsworth, Ronald L. Bibcode: 2012OExpr..2013711P Altcode: We deployed two wavelength calibrators based on laser frequency combs ("astro-combs") at an astronomical telescope. One astro-comb operated over a 100 nm band in the deep red (∼ 800 nm) and a second operated over a 20 nm band in the blue (∼ 400 nm). We used these red and blue astro-combs to calibrate a high-resolution astrophysical spectrograph integrated with a 1.5 m telescope, and demonstrated calibration precision and stability suffici ent to enable detection of changes in stellar radial velocity < 1 m/s. Title: Comparing Leakage Matrices Authors: Larson, T. P.; Schou, J.; Korzennik, S. G. Bibcode: 2011sdmi.confE..44L Altcode: The standard leakage matrix for global mode helioseismology is calculated assuming a value of zero for the P-angle, B-angle, and CCD offsets, and value of 1 AU for the observer distance. Since image center is not constant we vary this parameter so see what effect is has on the leaks and explore the possibility of using a leakage matrix averaged over pixel offsets. Since the B-angle and observer distance vary in a known way with time, we recompute the leakage matrix for realistic values of these parameters and repeat the fits to find out how the mode parameters are affected. Since previous studies have indicated certain systematic errors are associated with the apodization, we also compute leakage matrices for different apodizations, repeat the spherical harmonic decomposition with those apodizations, and fit these to see the effect on mode parameters. Lastly, we compare the leakage matrix computed at Stanford with a completely independent calculation in order to both verify our results and discover the source of any discrepancy. Title: Results from fitting 13+ years of GONG and MDI data at low and intermediate degrees Authors: Korzennik, S. G. Bibcode: 2011sdmi.confE..90K Altcode: I present the latest results from fitting modes at low and intermediate degrees (up to l=300 for the f-mode, l=200 for p-modes), using my state of the art fitting methodology. Time series of various lengths have been fitted, from a single 4608-day long epoch (64 times 72 day or 12.6 yr) down to 64 separate segments for the "traditional" 72-day long epochs, and including 32x, 16x, 8x, 4x and 2x 72-day long overlapping epochs. We used MDI time series of spherical harmonic coefficients computed using an improved spatial decomposition. This decomposition now includes our best estimate of the image plate scale and of the MDI instrumental image distortion. We used the GONG time series of spherical harmonic coefficients as generated by the GONG pipe-line (available up to l=200 only). The leakage matrices used for the fitting includes the distortion of the eigenfunctions by the solar differential rotation. The undistorted leakage matrices were carefully reviewed and independently recomputed. The effect of the leakage matrix (and its residual inadequacy) can be readily observed when using longer time series than the traditional 72 or 108-day long ones. We compare in details results from fitting GONG and MDI, using for the first time the same fitting code, although a different leakage matrix, and the exact same time span. Title: A determination of high degree mode parameters based on MDI observations Authors: Korzennik, S. G.; Rabello-Soares, M. C.; Schou, J.; Larson, T. Bibcode: 2011sdmi.confE..88K Altcode: We present the best to date determination of high degree mode parameters obtained from the longest full-disk high-resolution data set available over the 13 years of MDI operations. A ninety day long time series of full-disk two arc-second per pixel resolution dopplergrams were acquired in 2001, thanks to the high rate telemetry provided by the deep space network. These dopplergrams were decomposed using our best estimate of the image scale and the known components of MDI's image distortion. The spherical harmonics decomposition was carried out up to l=1000, and a sine multi-taper power spectrum estimator was used to generate power spectra for all degrees and all azimuthal orders up to l=1000. We used a large number of tapers to reduce the realization noise. Since at high degrees the individual modes blend into ridges, there is no reason to preserve a high spectral resolution. These power spectra were fitted for all degrees and all azimuthal orders, between l=100 and l=1000, and for all orders with substantial amplitude, generating in excess of 6 million individual estimate of frequencies, line-widths amplitudes and asymmetries, corresponding to some 6,000 singlets. Fitting at high degrees generates characteristics of the blended ridges, characteristics that do not correspond to the underlying mode characteristics. We used a sophisticated forward modeling of the mode to ridge blending to recover the best possible estimate of the underlying mode characteristics for the mode frequency, as well as the line-width, amplitude and asymmetry. We describe this modeling, as it has been recently fine tuned, and the iterative process used to refine its input parameters. Finally not only did we generate corrected mode characteristics and their uncertainties, but we computed the sensitivity of the model to its input set to best estimate the precision of the ridge to mode correction itself. This was carried out to assess the magnitude of any residual systematic errors in the final estimates of the mode characteristics. Title: High Accuracy Characterization of an Astro-comb with an FTS Authors: Glenday, Alex; Li, Chih-Hao; Phillips, David; Korzennik, Sylvain; Noah Chang, Guoqing; Chen, Li-Jin; Benedick, Andrew; Kaertner, Franz; Sasselov, Dimitar; Szentgyorgyi, Andrew; Walsworth, Ronald Bibcode: 2011APS..DMP.L1161G Altcode: Searches for extrasolar planets using the periodic Doppler shift of stellar lines are approaching Earth-like planet sensitivity. To find a 1-Earth-mass planet in an Earth-like orbit, an order of magnitude improvement in state-of-the-art radial velocity spectroscopy is necessary. An astro-comb, the combination of an ocatve-spanning laser frequency comb with a Fabry-Perot cavity, producing evenly spaced frequency markers with the potential for large wavelength coverage is a promising avenue towards improved wavelength calibration. Key to achieving high accuracy and long-term stability of the astro-comb is high-quality suppression of undesired comb laser lines by the Fabry-Perot filter cavity. Here we present a characterization of a green astro-comb produced by broadening a Ti:Sapphire laser using photonic crystal fiber (PCF) and filtered through zero group delay dispersion mirror sets optimized for the green. The characterization is performed using a high-resolution FTS constructed in our laboratory. Title: Calibration of an Astrophysical Spectrograph with an Astro-comb in the Visible Spectral Range Authors: Li, Chih-Hao; Glenday, Alex; Phillips, David; Korzennik, Sylvain; Noah Chang, Guoqing; Chen, Li-Jin; Benedick, Andrew; Kaertner, Franz; Sasselov, Dimitar; Szentgyorgyi, Andrew; Walsworth, Ronald Bibcode: 2011APS..DMP.J5005L Altcode: Searches for extrasolar planets using the periodic Doppler shift of stellar lines are approaching Earth-like planet sensitivity. To find a 1-Earth-mass planet in an Earth-like orbit, an order of magnitude improvement in state-of-the-art radial velocity spectroscopy is necessary. An astro-comb, the combination of an ocatve-spanning laser frequency comb with a Fabry-Perot cavity, producing evenly spaced frequency markers with the potential for large wavelength coverage is a promising avenue towards improved wavelength calibration. Here we demonstrate the calibration of a high-resolution astrophysical spectrograph below the 50 cm/s level in the visible spectral range around 420 nm using an octave-spanning Ti:Sapphire laser and an ultra-low dispersion Fabry-Perot filter cavity adjusted for a mode spacing of approximately 50 GHz. Modeling of spectrograph response function and overall system stability and reproducibility will be described. Title: Red, Green, and Blue Astro-combs Authors: Phillips, David; Glenday, Alex; Li, Chih-Hao; Korzennik, Sylvain; Noah Chang, Guoqing; Chen, Li-Jin; Benedick, Andrew; Kaertner, Franz; Sasselov, Dimitar; Szentgyorgyi, Andrew; Walsworth, Ronald Bibcode: 2011APS..DMP.L1162P Altcode: Searches for extrasolar planets using the periodic Doppler shift of stellar lines are approaching Earth-like planet sensitivity. Astro-combs, a combination of an octave spanning femtosecond laser and a mode-filtering cavity provide a likely route to increased calibration precision and accuracy. We present results from three astro-combs operating in the red/near-IR, green and blue spectral ranges. Light from a 1-GHz, octave-spanning Ti:Sapphire laser is filtered by a Fabry-Perot Cavity (FPC) constructed from Doubly-Chirped Mirrors to produce a red astro-comb with 100 nm of optical bandwidth. This astro-comb has calibrated an astrophysical spectrograph at the 1 m/s level. In the blue astro-comb, Ti:Sapphire comb light, doubled in a BBO crystal is filtered to 50 GHz mode spacing with an FPC. The blue astro-comb has performed 50 cm/s calibrations. In the ``green'' astro-comb, light from the 1 GHz Ti:Sapphire comb laser is broadened in a photonic crystal fiber optimized to produce light in the green. This 1-GHz spaced green light is then filtered to roughly 40 GHz via an FPC with zero group delay dispersion mirrors, providing approximately 50 nm of astro-comb light centered near 550 nm. Title: A Comparison Of Solar High-degree p-mode Parameters From HMI And MDI Authors: Rabello-Soares, M. Cristina; Bogart, R.; Korzennik, S.; Larson, T.; Reiter, J.; Rhodes, E.; Schou, J. Bibcode: 2011SPD....42.1606R Altcode: 2011BAAS..43S.1606R Solar acoustic modes have been successfully used to make inferences about the solar interior. The comparison of independent contemporaneous data sets is important to test the reliability of our inferences. Here we compare helioseismic data from the Michelson Doppler Imager (MDI) on board SOHO with Helioseismic and Magnetic Imager (HMI) on board SDO using spherical harmonic decomposition and ring-diagram analysis. We will focus on the analysis of high-degree modes. They propagate through the outer layers of the Sun giving valuable information about this region. This interesting region is the seat of the near-surface shear layer, where the excitation and damping mechanisms are believed to be concentrated and where the effects of the equation of state are felt most strongly. Title: The Solar Rotation and its Evolution During Cycle 23 Authors: Korzennik, Sylvain G.; Eff-Darwich, A. Bibcode: 2011AAS...21822422K Altcode: 2011BAAS..43G22422K We present the most exhaustive and accurate inferences of the internal solar rotation rate and its evolution during solar cycle 23. A full solar cycle of MDI observations have been analyzed using our state of the art fitting methodology. Time series of various lengths have been fitted, from a single 4608-day long epoch (64 times 72 day or 12.6 yr) down to 64 separate segments for the "traditional" 72-day long epochs. We used time series of spherical harmonic coefficients computed by the MDI group but using an improved spatial decomposition. This decomposition now includes our best estimate of the image plate scale and of the MDI instrumental image distortion. The leakage matrix used for the fitting includes the distortion of the eigenfunctions by the solar differential rotation, and the undistorted leakage matrix was itself carefully reviewed and independently recomputed. Rotation inversions were carried out for all the available mode sets, fitted for that epoch and all available segments, including the MDI and GONG "pipe-line" sets. The improved inversions we used is an iterative methodology based on a least-squares regularization. It also implement a model grid optimization derived from the actual information in the input set. This optimized model grid is itself irregular, namely with a variable number of latitudes at different depths. We not only present the most accurate mean rotation rate, but also how its derivation may still be affected by uncertainties in the mode fitting (in particular the leakage matrix). We also focus on the change of the rotation rate with activity levels and how well these changes are significantly assessed at higher latitudes as well as deeper in the solar interior, down to the base of the convection zone. Title: The solar core as never seen before Authors: Eff-Darwich, A.; Korzennik, S. G. Bibcode: 2011JPhCS.271a2043E Altcode: One of the main drawbacks in the analysis of the dynamics of the solar core comes from the lack of consistent data sets that cover the low and intermediate degree range (ell = 1,200). It is usually necessary to merge data obtained from different instruments and/or fitting methodologies and hence one introduces undesired systematic errors. In contrast, we present the results of analyzing MDI rotational splittings derived by a single fitting methodology applied to 4608-, 2304-, etc..., down to 182-day long time series. The direct comparison of these data sets and the analysis of the numerical inversion results have allowed us to constrain the dynamics of the solar core and to establish the accuracy of these data as a function of the length of the time-series. Title: The rotation rate and its evolution derived from improved mode fitting and inversion methodology Authors: Korzennik, S. G.; Eff-Darwich, A. Bibcode: 2011JPhCS.271a2067K Altcode: We present inferences of the internal solar rotation rate and its evolution during solar cycle 23. A full solar cycle of MDI observations have been analyzed using an improved fitting methodology and using time series of various lengths, up to a single 4,608 day long epoch (64 times 72 days or 12.6 yr). We used time series of spherical harmonic coefficients computed by the MDI group, including those resulting from using their improved spatial decomposition. This decomposition includes our best estimate of the image plate scale and of the MDI instrumental image distortion. The leakage matrix used in the fitting includes the effect of the distortion of the eigenfunctions by the solar differential rotation, while the undistorted leakage matrix was itself carefully reviewed and independently recomputed. Rotation inversions were carried out for all available mode sets, fitted for that epoch, including the MDI and GONG "pipe-line" values. The improved inversion method uses an iterative methodology based on a least-squares regularization, but with an optimal model grid determined by the actual information in the input set. This method also allows us to use an optimized irregular grid, with a variable number of latitudes at different depths. Title: Accurate Mapping of the Torsional Oscillations: a Trade-Off Study between Time Resolution and Mode Characterization Precision Authors: Eff-Darwich, A.; Korzennik, S. G. Bibcode: 2011JPhCS.271a2078E Altcode: One salient result of global helioseismology is the mapping of the so-called torsional oscillations below the solar surface. These subsurface flows are inferred by inverting rotational frequency splitting sets of global modes. These flows extend down to a depth of at least 0.8 R, and are likely associated with the activity cycle of our star. To better understand the mechanisms that drive the solar cycle we need to accurately map these flows, and characterize precisely their penetration depth and their temporal behavior.

We present a study of the spatial (depth and latitude) and temporal variations of the solar rotation rate associated with the torsional oscillation based on state-of-the-art mode fitting of time series of various lengths of MDI observations, namely 1456-, 728-, 364- and 182-day long time series. Such approach allows us to better estimate how much significant information can be extracted from the different time spans and hence trade off time resolution for precision in the inverted profiles resulting from the different mode sets. Title: Advances in solar rotation rate inferences: Unstructured grid inversions and improved rotational splittings Authors: Eff-Darwich, A.; Korzennik, S. G.; García, R. A. Bibcode: 2010AN....331..890E Altcode: We present a new inversion methodology that adapts the inversion grid in both radius and co-latitude to the data set and solves the inversion problem through an iterative procedure. This method was tested on state-of-the-art global mode frequency splittings to assess the solar interior rotation rate and its temporal variation. We also explore the influence of different data sets on the interpretation of the dynamics of the solar interior, particularly the spatial extend of the torsional oscillations. Title: New Observational Constraints on the υ Andromedae System with Data from the Hubble Space Telescope and Hobby-Eberly Telescope Authors: McArthur, Barbara E.; Benedict, G. Fritz; Barnes, Rory; Martioli, Eder; Korzennik, Sylvain; Nelan, Ed; Butler, R. Paul Bibcode: 2010ApJ...715.1203M Altcode: We have used high-cadence radial velocity (RV) measurements from the Hobby-Eberly Telescope with existing velocities from the Lick, Elodie, Harlan J. Smith, and Whipple 60'' telescopes combined with astrometric data from the Hubble Space Telescope Fine Guidance Sensors to refine the orbital parameters and determine the orbital inclinations and position angles of the ascending node of components υ And A c and d. With these inclinations and using M * = 1.31M sun as a primary mass, we determine the actual masses of two of the companions: υ And A c is 13.98+2.3 -5.3 M JUP, and υ And A d is 10.25+0.7 -3.3 M JUP. These measurements represent the first astrometric determination of mutual inclination between objects in an extrasolar planetary system, which we find to be 29fdg9 ± 1°. The combined RV measurements also reveal a long-period trend indicating a fourth planet in the system. We investigate the dynamic stability of this system and analyze regions of stability, which suggest a probable mass of υ And A b. Finally, our parallaxes confirm that υ And B is a stellar companion of υ And A.

Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Based on observations obtained with the Hobby-Eberly Telescope, which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Stanford University, Ludwig-Maximilians-Universitt Mnchen, and Georg-August-Universität Göttingen. Title: In-situ determination of astro-comb calibrator lines to better than 10 cm s^-1 Authors: Li, Chih-Hao; Glenday, Alexander G.; Benedick, Andrew J.; Chang, Guoqing; Chen, Li-Jin; Cramer, Claire; Fendel, Peter; Furesz, Gabor; Kärtner, Franz X.; Korzennik, Sylvain; Phillips, David F.; Sasselov, Dimitar; Szentgyorgyi, Andrew; Walsworth, Ronald L. Bibcode: 2010OExpr..1813239L Altcode: 2010arXiv1006.0492L Improved wavelength calibrators for high-resolution astrophysical spectrographs will be essential for precision radial velocity (RV) detection of Earth-like exoplanets and direct observation of cosmological deceleration. The astro-comb is a combination of an octave-spanning femtosecond laser frequency comb and a Fabry-Pérot cavity used to achieve calibrator line spacings that can be resolved by an astrophysical spectrograph. Systematic spectral shifts associated with the cavity can be 0.1-1 MHz, corresponding to RV errors of 10-100 cm/s, due to the dispersive properties of the cavity mirrors over broad spectral widths. Although these systematic shifts are very stable, their correction is crucial to high accuracy astrophysical spectroscopy. Here, we demonstrate an \emph{in-situ} technique to determine the systematic shifts of astro-comb lines due to finite Fabry-Pérot cavity dispersion. The technique is practical for implementation at a telescope-based spectrograph to enable wavelength calibration accuracy better than 10 cm/s. Title: New Observational Constraints on the υ Andromedae System with Data from the Hubble Space Telescope and Hobby Eberly Telescope Authors: McArthur, Barbara; Benedict, G. F.; Barnes, R.; Martioli, E.; Korzennik, S.; Nelan, E.; Butler, R. P. Bibcode: 2010AAS...21642510M Altcode: We have used high-cadence radial velocity measurements from the Hobby-Eberly Telescope with existing velocities from the Lick, Elodie, Harlan J. Smith and Whipple 60” telescopes combined with astrometric data from the Hubble Space Telescope Fine Guidance Sensors to refine the orbital parameters and determine the orbital inclinations and position angles of the ascending node of components υ And A c and d. With these inclinations and using M = 1.31M⊙ as a primary mass we determine the actual masses of two of the companions: υ And A c is13.98+2.3 Mjup, and υ And A d is 10.25+0.7 Mjup. These measurements represent the first astrometric determination of mutual inclination between objects in an extrasolar planetary system. The combined radial velocity measurements also reveal a long period trend indicating a fourth planet in the system. We investigate the dynamic stability of this system and analyze regions of stability, which suggest a probable mass of υ And A b. Finally, our parallaxes confirm that υ And B is a stellar companion of υ And A. Support for this work was provided by NASA through grants GO-09971, GO-10103, and GO-11210 from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under NASA contract NAS5-26555. Title: The Asteroseismic Potential of Kepler: First Results for Solar-Type Stars Authors: Chaplin, W. J.; Appourchaux, T.; Elsworth, Y.; García, R. A.; Houdek, G.; Karoff, C.; Metcalfe, T. S.; Molenda-Żakowicz, J.; Monteiro, M. J. P. F. G.; Thompson, M. J.; Brown, T. M.; Christensen-Dalsgaard, J.; Gilliland, R. L.; Kjeldsen, H.; Borucki, W. J.; Koch, D.; Jenkins, J. M.; Ballot, J.; Basu, S.; Bazot, M.; Bedding, T. R.; Benomar, O.; Bonanno, A.; Brandão, I. M.; Bruntt, H.; Campante, T. L.; Creevey, O. L.; Di Mauro, M. P.; Doǧan, G.; Dreizler, S.; Eggenberger, P.; Esch, L.; Fletcher, S. T.; Frandsen, S.; Gai, N.; Gaulme, P.; Handberg, R.; Hekker, S.; Howe, R.; Huber, D.; Korzennik, S. G.; Lebrun, J. C.; Leccia, S.; Martic, M.; Mathur, S.; Mosser, B.; New, R.; Quirion, P. -O.; Régulo, C.; Roxburgh, I. W.; Salabert, D.; Schou, J.; Sousa, S. G.; Stello, D.; Verner, G. A.; Arentoft, T.; Barban, C.; Belkacem, K.; Benatti, S.; Biazzo, K.; Boumier, P.; Bradley, P. A.; Broomhall, A. -M.; Buzasi, D. L.; Claudi, R. U.; Cunha, M. S.; D'Antona, F.; Deheuvels, S.; Derekas, A.; García Hernández, A.; Giampapa, M. S.; Goupil, M. J.; Gruberbauer, M.; Guzik, J. A.; Hale, S. J.; Ireland, M. J.; Kiss, L. L.; Kitiashvili, I. N.; Kolenberg, K.; Korhonen, H.; Kosovichev, A. G.; Kupka, F.; Lebreton, Y.; Leroy, B.; Ludwig, H. -G.; Mathis, S.; Michel, E.; Miglio, A.; Montalbán, J.; Moya, A.; Noels, A.; Noyes, R. W.; Pallé, P. L.; Piau, L.; Preston, H. L.; Roca Cortés, T.; Roth, M.; Sato, K. H.; Schmitt, J.; Serenelli, A. M.; Silva Aguirre, V.; Stevens, I. R.; Suárez, J. C.; Suran, M. D.; Trampedach, R.; Turck-Chièze, S.; Uytterhoeven, K.; Ventura, R.; Wilson, P. A. Bibcode: 2010ApJ...713L.169C Altcode: 2010arXiv1001.0506C We present preliminary asteroseismic results from Kepler on three G-type stars. The observations, made at one-minute cadence during the first 33.5 days of science operations, reveal high signal-to-noise solar-like oscillation spectra in all three stars: about 20 modes of oscillation may be clearly distinguished in each star. We discuss the appearance of the oscillation spectra, use the frequencies and frequency separations to provide first results on the radii, masses, and ages of the stars, and comment in the light of these results on prospects for inference on other solar-type stars that Kepler will observe. Title: Calibration of an Astrophysical Spectrograph with an Astro-comb Authors: Phillips, David F.; Glenday, Alex; Li, Chih-Hao; Cramer, Claire; Korzennik, Sylvain; Noah Chang, Guoqing; Chen, Li-Jin; Benedick, Andrew; Kaertner, Franz X.; Sasselov, Dimitar; Szentgyorgyi, Andrew; Walsworth, Ronald L. Bibcode: 2010APS..DMP.E1050P Altcode: Searches for extrasolar planets using the periodic Doppler shift of stellar lines are approaching Earth-like planet sensitivity. To find a 1-Earth-mass planet in an Earth-like orbit, an order of magnitude improvement in state-of-the-art radial velocity spectroscopy is necessary. An astro-comb, the combination of an ocatve-spanning laser frequency comb with a Fabry-Perot cavity, producing evenly spaced frequency markers with the potential for large wavelength coverage is a promising avenue towards improved wavelength calibration. Here we demonstrate the calibration of a high-resolution astrophysical spectrograph below the 1 m/s level in the 800-900 nm spectral band using an octave-spanning Ti:Sapphire laser and an ultra-low dispersion Fabry-Perot filter cavity adjusted for a mode spacing of approximately 31 GHz. Modeling of spectrograph response function and overall system stability and reproducibility will be described. Title: Laboratory Demonstration of a Green Astro-comb Authors: Li, Chih-Hao; Glenday, Alex; Phillips, David F.; Korzennik, Sylvain; Noah Chang, Guoqing; Benedick, Andrew; Chen, Li-Jin; Kaertner, Franz X.; Sasselov, Dimitar; Szentgyorgyi, Andrew; Walsworth, Ronald Bibcode: 2010APS..DMP.E1049L Altcode: Searches for extrasolar planets using the periodic Doppler shift of stellar lines are approaching Earth-like planet sensitivity. Astro-combs, a combination of an octave spanning femtosecond laser and a mode-filtering cavity provide a likely route to increased calibration precision and accuracy. Initial astro-comb demonstrations have been performed in the near infrared where broadband lasers are available. Here we present initial laboratory results on a ``green'' astro-comb providing approximately 50 nm of stable astro-comb light centered near 550 nm. Light from a 1 GHz, octave-spanning Ti:Sapphire laser is broadened in a photonic crystal fiber optimized to produce light in the green. This 1 GHz spaced green light is then filtered to roughly 30 GHz mode spacing via a Fabry-Perot cavity with ultra-low dispersion mirrors. Current progress on the characterization of this green astro-comb will be presented. Title: On the Frequency of Gas Giant Planets in the Metal-Poor Regime Authors: Sozzetti, A.; Latham, D. W.; Torres, G.; Carney, B. W.; Laird, J. B.; Stefanik, R. P.; Boss, A. P.; Korzennik, S. Bibcode: 2010IAUS..265..416S Altcode: We present an analysis of three years of precision radial velocity measurements of 160 metal-poor stars observed with Keck/HIRES. We report on variability and long-term velocity trends for each star in our sample. We identify several long-term, low-amplitude radial-velocity variables worthy of follow-up with direct imaging techniques. We place lower limits on the detectable companion mass as a function of orbital period. None of the stars in our sample exhibits radial-velocity variations compatible with the presence of Jovian planets with periods shorter than the survey duration (3 yr). The resulting average frequency of gas giants orbiting metal-poor dwarfs with -2.0≤[Fe/H]≤ -0.6 is fp < 0.67%. By combining our dataset with the Fischer & Valenti (2005) uniform sample, we confirm that the likelihood of a star to harbor a planet more massive than Jupiter within 2 AU is a steeply rising function of the host's metallicity. However, the data for stars with -1.0≤[Fe/H]≤ 0.0 are compatible, in a statistical sense, with a constant occurrence rate fp≃1%. Our results usefully inform theoretical studies of the process of giant planet formation across two orders of magnitude in metallicity. Title: The Keck metal-poor planet search . On the frequency of gas giant planets in the metal-poor regime Authors: Sozzetti, A.; Latham, D. W.; Torres, G.; Boss, A. P.; Carney, B. W.; Korzennik, S. G.; Laird, J. B.; Stefanik, R. P. Bibcode: 2010MSAIS..14..173S Altcode: We present an analysis of three years of precision radial velocity measurements of 160 metal-poor stars observed with Keck/HIRES. We report on variability and long-term velocity trends for each star in our sample. We identify several long-term, low-amplitude radial-velocity variables worthy of follow-up with direct imaging techniques. We place lower limits on the detectable companion mass as a function of orbital period. None of the stars in our sample exhibits radial-velocity variations compatible with the presence of Jovian planets with periods shorter than the survey duration (3 yr). The resulting average frequency of gas giants orbiting metal-poor dwarfs with -2.0≲[Fe/H]≲ -0.6 is f_p<0.67%. By combining our dataset with the Fischer & Valenti (2005) uniform sample, we confirm that the likelihood of a star to harbor a planet more massive than Jupiter within 2 AU is a steeply rising function of the host's metallicity. However, the data for stars with -1.0≲[Fe/H]≲ 0.0 are compatible, in a statistical sense, with a constant occurrence rate f_p≃1%. Our results usefully inform theoretical studies of the process of giant planet formation across two orders of magnitude in metallicity. Title: Search for Structural Variations of the Near-Surface Layers of the Sun during the Solar Cycle Authors: Rabello-Soares, M. C.; Korzennik, S. G. Bibcode: 2009ASPC..416..277R Altcode: Acoustic mode frequencies, with degree up to 900, observed by Michelson Doppler Imager (MDI) from 1995 to 2005 were analyzed to determine if there are any changes in the near-surface layers of the solar structure with the solar cycle. The inclusion of high-degree modes allowed the determination of the sound speed up to 0.993 Rsun. Title: On the Dependence of our Inferences about the Solar Internal Rotation on the Frequency Fitting Methodology Authors: Korzennik, S. G.; Eff-Darwich, A. Bibcode: 2009ASPC..416..221K Altcode: We show how inferences of the solar internal rotation rate depend on different aspects of the mode fitting procedure. We study the stability of the rotation rate and its variation with time through inversions of frequency splittings data sets computed from fitting 364, 728 and 2088-day long Michelson Doppler Imager (MDI) time series, 72-day long MDI time series and 108-day long Global Oscillation Network Group (GONG) time series with different fitting methodologies and acquired during Cycle 23.

The frequency splittings obtained from MDI and GONG time-series through different fitting techniques are inverted to analyze the effect of the fitting methodology on the inferred rotation rate. In particular, we present inversions based on either individual frequencies (as derived by the fitting technique developed by Korzennik 2005), or frequency splittings parametrized in terms of Clebsh-Gordon (CG) coefficients. We present the impact of using either individual frequencies or CG coefficients on the inversion results. Title: Impact of Low-Frequency p Modes on the Inversions of the Internal Rotation of the Sun Authors: Salabert, D.; Eff-Darwich, A.; Howe, R.; Korzennik, S. G. Bibcode: 2009ASPC..416..253S Altcode: 2008arXiv0811.1745S We used the m-averaged spectrum technique ("collapsogram") to extract the low-frequency solar p-mode parameters of low- and intermediate-angular degrees (l ≤ 35) in long time series of Global Oscillation Network Group (GONG) and Michelson Doppler Imager (MDI) observations. Rotational splittings and central frequencies have been measured down to ≍850 μHz, including predicted modes which have not been measured previously. Both GONG and MDI frequency splitting data sets were numerically inverted to extract the internal solar rotation rate. The impact of the very low-frequency observables and the differences between GONG and MDI data sets on the inversion results are also analyzed. Title: A Tunable Laser System for the Wavelength Calibration of Multi-Object Spectrographs Authors: Cramer, Claire; Brown, S.; Dupree, A. K.; Korzennik, S. G.; Lykke, K. R.; Szentgyorgyi, A. Bibcode: 2009AAS...21361105C Altcode: High-resolution spectroscopy is an essential technique in the search for extra-solar earths, time variation of fundamental constants, and dark matter in the galactic halo. A problem that must be addressed in order to improve upon existing measurements is the wavelength calibration of multi-object echelle spectrographs (MOS). Precise MOS wavelength calibration is largely an unsolved problem. Optimally, calibration light should illuminate the spectrograph pupil with the same intensity distribution as a science object. This is best achieved by making the path of the calibration light and star light follow the same optical path. For a single object spectrograph, this is straightforward. The difficulty arises when hundreds of apertures (fibers) located in different places in the focal plane must be calibrated in a reasonable amount of time. The ThAr calibration lamps typically used for high-resolution spectroscopy are too faint to reflect from a dome screen that acts as a proxy for an infinite conjugate, and shining lamp light directly onto the focal plane leads to position- and fiber-dependent shifts and distortions of the wavelength scale. We present preliminary results from a scheme we have deployed at the MMT 6.5m telescope to wavelength calibrate the Hectochelle MOS with tunable lasers. Narrowband tunable lasers are bright enough to compensate dome screen attenuation, and can be scanned over a typical MOS free spectral range of 10 nm in under a minute. We record the wavelengths in each laser calibration scan with a commercial scanning Michelson interferometer, which gives a precision and accuracy of 50 m/s for each line, comparable to the photon-limited Doppler precision of a typical multi-object echelle spectrograph. In this poster, we describe the tunable laser system, compare wavelength solutions generated from the tunable laser system and ThAr lamps, and present examples of astronomical data calibrated with the laser. Title: What Can We Learn on the Structure and the Dynamics of the Solar Core with g Modes? Authors: Mathur, S.; Ballot, J.; Eff-Darwich, A.; García, R. A.; Jiménez-Reyes, S. J.; Korzennik, S. G.; Turck-Chièze, S. Bibcode: 2009ASPC..416..215M Altcode: 2008arXiv0810.2031M The detection of the signature of dipole gravity modes has opened the path to study the solar inner radiative zone. Indeed, g modes should be the best probes to infer the properties of the solar nuclear core that represents more than half of the total mass of the Sun. Concerning the dynamics of the solar core, we can study how future observations of individual g modes could enhance our knowledge of the rotation profile of the deep radiative zone. Applying inversions on a set of real p-mode splittings coupled with either one or several g modes, we have checked the improvement of the inferred rotation profile when different error bars are considered for the g modes. Moreover, using a new methodology based on the analysis of the almost constant separation of the dipole gravity modes, we can introduce new constraints on solar models. For that purpose, we can compare g-mode predictions computed from several models including different physical inputs with the g-mode asymptotic signature detected in Global Oscillations at Low Frequencies (GOLF) data and calculate the correlation. This work shows the great consistency between the signature of dipole gravity modes and our knowledge of p-modes: incompatibility of data with a present standard model including the Asplund composition. Title: Results from Fitting Long and Very-Long MDI Time-Series at Low and Intermediate Degrees Authors: Korzennik, S. G. Bibcode: 2009ASPC..416..315K Altcode: I present results from fitting long and very-long MDI time series of spherical harmonics coefficients, at low and intermediate degrees. The fitting methodology used, initially developed for very-long time series, incorporates several key aspects not present in the "production" Michelson Doppler Imager (MDI) (or Global Oscillation Network Group (GONG)) fitting methodologies. The fitting has since been extended to higher degrees and applied to shorter time series, resulting in fitting 2088-day long, as well as, 728, 364 and 182-day long time series, covering nearly 11 years of observations. The 2088-day long time series has been fitting up to l=125. Nine overlapping 728-day long time series have been fitted up to l=95, while nineteen and thirty nine overlapping 364 and 182-day long time series, respectively, have been fitted up to l=47. Title: A Keck HIRES Doppler Search for Planets Orbiting Metal-Poor Dwarfs. II. On the Frequency of Giant Planets in the Metal-Poor Regime Authors: Sozzetti, Alessandro; Torres, Guillermo; Latham, David W.; Stefanik, Robert P.; Korzennik, Sylvain G.; Boss, Alan P.; Carney, Bruce W.; Laird, John B. Bibcode: 2009ApJ...697..544S Altcode: 2009arXiv0902.4802S We present an analysis of three years of precision radial velocity (RV) measurements of 160 metal-poor stars observed with HIRES on the Keck 1 telescope. We report on variability and long-term velocity trends for each star in our sample. We identify several long-term, low-amplitude RV variables worthy of followup with direct imaging techniques. We place lower limits on the detectable companion mass as a function of orbital period. Our survey would have detected, with a 99.5% confidence level, over 95% of all companions on low-eccentricity orbits with velocity semiamplitude K gsim 100 m s-1, or Mp sin i gsim 3.0 M J(P/yr)(1/3), for orbital periods P lsim 3 yr. None of the stars in our sample exhibits RV variations compatible with the presence of Jovian planets with periods shorter than the survey duration. The resulting average frequency of gas giants orbiting metal-poor dwarfs with -2.0lsim[Fe/H]lsim-0.6 is fp < 0.67% (at the 1σ confidence level). We examine the implications of this null result in the context of the observed correlation between the rate of occurrence of giant planets and the metallicity of their main-sequence solar-type stellar hosts. By combining our data set with the Fischer & Valenti (2005) uniform sample, we confirm that the likelihood of a star to harbor a planet more massive than Jupiter within 2 AU is a steeply rising function of the host's metallicity. However, the data for stars with -1.0lsim[Fe/H]lsim0.0 are compatible, in a statistical sense, with a constant occurrence rate fp sime 1%. Our results can usefully inform theoretical studies of the process of giant-planet formation across two orders of magnitude in metallicity. Title: A New Spectroscopic and Photometric Analysis of the Transiting Planet Systems TrES-3 and TrES-4 Authors: Sozzetti, Alessandro; Torres, Guillermo; Charbonneau, David; Winn, Joshua N.; Korzennik, Sylvain G.; Holman, Matthew J.; Latham, David W.; Laird, John B.; Fernandez, José; O'Donovan, Francis T.; Mandushev, Georgi; Dunham, Edward; Everett, Mark E.; Esquerdo, Gilbert A.; Rabus, Markus; Belmonte, Juan A.; Deeg, Hans J.; Brown, Timothy N.; Hidas, Márton G.; Baliber, Nairn Bibcode: 2009ApJ...691.1145S Altcode: 2008arXiv0809.4589S We report new spectroscopic and photometric observations of the parent stars of the recently discovered transiting planets TrES-3 and TrES-4. A detailed abundance analysis based on high-resolution spectra yields [Fe/H] = -0.19 ± 0.08, T eff = 5650 ± 75 K, and log g = 4.4 ± 0.1 for TrES-3, and [Fe/H] = +0.14 ± 0.09, T eff = 6200 ± 75 K, and log g = 4.0 ± 0.1 for TrES-4. The accuracy of the effective temperatures is supported by a number of independent consistency checks. The spectroscopic orbital solution for TrES-3 is improved with our new radial velocity measurements of that system, as are the light-curve parameters for both systems based on newly acquired photometry for TrES-3 and a reanalysis of existing photometry for TrES-4. We have redetermined the stellar parameters taking advantage of the strong constraint provided by the light curves in the form of the normalized separation a/R sstarf (related to the stellar density) in conjunction with our new temperatures and metallicities. The masses and radii we derive are M sstarf = 0.928+0.028 -0.048 M sun, R sstarf = 0.829+0.015 -0.022 R sun, and M sstarf = 1.404+0.066 -0.134 M sun, R sstarf = 1.846+0.096 -0.087 R sun for TrES-3 and TrES-4, respectively. With these revised stellar parameters, we obtain improved values for the planetary masses and radii. We find Mp = 1.910+0.075 -0.080 M Jup, Rp = 1.336+0.031 -0.036 R Jup for TrES-3, and Mp = 0.925 ± 0.082 M Jup, Rp = 1.783+0.093 -0.086 R Jup for TrES-4. We confirm TrES-4 as the planet with the largest radius among the currently known transiting hot Jupiters. Title: YAOPBM—II: extension to higher degrees and to shorter time series Authors: Korzennik, S. G. Bibcode: 2008JPhCS.118a2082K Altcode: In 2005, I presented a new fitting methodology (Yet AnOther Peak Bagging Method -YAOPBM), derived for very-long time series (2088-day-long) and applied it to low degree modes, ι <= 25. That very-long time series was also sub-divided into shorter segments (728-day-long) that were each fitted over the same range of degrees, to estimate changes with solar activity levels.

I present here the extension of this method in several 'directions': a) to substantially higher degrees (ι <= 125); b) to shorter time series (364- and 182-day-long); and c) to additional 728-day-long segments, covering now some 10 years of observations.

I discuss issues with the fitting, namely the leakage matrix, and the f- and p1 mode at very low frequencies, and I present some of the characteristics of the observed temporal changes. Title: High degree modes & instrumental effects Authors: Korzennik, S. G.; Rabello-Soares, M. C.; Schou, J. Bibcode: 2008JPhCS.118a2027K Altcode: Full-disk observations taken with the Michelson Doppler Imager (MDI) on board the Solar and Heliospheric Observatory (SOHO) spacecraft, or the upgraded Global Oscillations Network Group (GONG) instruments, have enough spatial resolution to resolve modes up to ι = 1000 if not ι = 1500. The inclusion of such high-degree modes (i.e., ι <= 1000) improves dramatically inferences near the surface. Unfortunately, observational and instrumental effects cause the characterization of high degree modes to be quite complicated.

Indeed, the characteristics of the solar acoustic spectrum are such that, for a given order, mode lifetimes get shorter and spatial leaks get closer in frequency as the degree of a mode increases. A direct consequence of this property is that individual modes are resolved only at low and intermediate degrees. At high degrees the individual modes blend into ridges and the power distribution of the ridge defines the ridge central frequency, masking the underlying mode frequency. An accurate model of the amplitude of the peaks that contribute to the ridge power distribution is needed to recover the underlying mode frequency from fitting the ridge.

We present a detailed discussion of the modeling of the ridge power distribution, and the contribution of the various observational and instrumental effects on the spatial leakage, in the context of the MDI instrument. We have constructed a physically motivated model (rather than an ad hoc correction scheme) that results in a methodology that can produce unbiased estimates of high-degree modes. This requires that the instrumental characteristics are well understood, a task that has turned out to pose a major challenge.

We also present our latest results, where most of the known instrumental and observational effects that affect specifically high-degree modes were removed. These new results allow us to focus our attention on changes with solar activity.

Finally, we present variations of mode frequencies resulting from solar activity over most of solar cycle 23. We present the correlation of medium and high degree modes with different solar indices. Our results confirm that the frequency shift scaled by the relative mode inertia is a function of frequency alone and follows a simple power law. Title: Analysis of MDI High-Degree Mode Frequencies and their Rotational Splittings Authors: Rabello-Soares, M. C.; Korzennik, S. G.; Schou, J. Bibcode: 2008SoPh..251..197R Altcode: 2008arXiv0808.2838R; 2008SoPh..tmp..133R We present a detailed analysis of solar acoustic mode frequencies and their rotational splittings for modes with degree up to 900. They were obtained by applying spherical harmonic decomposition to full-disk solar images observed by the Michelson Doppler Imager onboard the Solar and Heliospheric Observatory spacecraft. Global helioseismology analysis of high-degree modes is complicated by the fact that the individual modes cannot be isolated, which has limited so far the use of high-degree data for structure inversion of the near-surface layers (r>0.97R⊙). In this work, we took great care to recover the actual mode characteristics using a physically motivated model which included a complete leakage matrix. We included in our analysis the following instrumental characteristics: the correct instantaneous image scale, the radial and non-radial image distortions, the effective position angle of the solar rotation axis, and a correction to the Carrington elements. We also present variations of the mode frequencies caused by the solar activity cycle. We have analyzed seven observational periods from 1999 to 2005 and correlated their frequency shift with four different solar indices. The frequency shift scaled by the relative mode inertia is a function of frequency alone and follows a simple power law, where the exponent obtained for the p modes is twice the value obtained for the f modes. The different solar indices present the same result. Title: Influence of Low-Degree High-Order p-Mode Splittings on the Solar Rotation Profile Authors: García, R. A.; Mathur, S.; Ballot, J.; Eff-Darwich, A.; Jiménez-Reyes, S. J.; Korzennik, S. G. Bibcode: 2008SoPh..251..119G Altcode: 2008SoPh..tmp...43G; 2008arXiv0802.1510G The solar rotation profile is well constrained down to about 0.25R⊙ thanks to the study of acoustic modes. Since the radius of the inner turning point of a resonant acoustic mode is inversely proportional to the ratio of its frequency to its degree, only the low-degree p modes reach the core. The higher the order of these modes, the deeper they penetrate into the Sun and thus they carry more diagnostic information on the inner regions. Unfortunately, the estimates of frequency splittings at high frequency from Sun-as-a-star measurements have higher observational errors because of mode blending, resulting in weaker constraints on the rotation profile in the inner core. Therefore inversions for the solar internal rotation use only modes below 2.4 mHz for ℓ≤3. In the work presented here, we used an 11.5-year-long time series to compute the rotational frequency splittings for modes ℓ≤3 using velocities measured with the GOLF instrument. We carried out a theoretical study of the influence of the low-degree modes in the region from 2 to 3.5 mHz on the inferred rotation profile as a function of their error bars. Title: Deploying comb and tunable lasers to enable precision radial velocity surveys Authors: Szentgyorgyi, Andrew; Cramer, Claire; Benedick, Andrew; Glenday, Alexander G.; Kaertner, Franz X.; Korzennik, Sylvain; Li, Chih-Hao; Ordway, Mark P.; Phillips, David F.; Sasselov, Dimitar; Walsworth, Ronald L. Bibcode: 2008SPIE.7014E..1WS Altcode: 2008SPIE.7014E..64S We describe recent progress toward developing optical frequency laser combs and tunable laser to the problem of more precise calibration of high dispersion astronomical spectra, thus permitting radial velocity determinations in the few cm/sec regime. We describe two programs in progress to calibrate both a cross dispersed echelle spectrograph with a laser comb and to calibrate a multiobject echelle spectrograph with a tunable laser. Title: Analysis of the Sensitivity of Solar Rotation to Helioseismic Data from GONG, GOLF, and MDI Observations Authors: Eff-Darwich, A.; Korzennik, S. G.; Jiménez-Reyes, S. J.; García, R. A. Bibcode: 2008ApJ...679.1636E Altcode: 2008arXiv0802.3604E Accurate determination of the rotation rate in the radiative zone of the Sun from helioseismic observations requires rotational frequency splittings of exceptional quality as well as reliable inversion techniques. Here we present inferences based on mode parameters calculated from 2088 day MDI, GONG, and GOLF time series that were fitted to estimate very low frequency rotational splittings (ν < 1.7 mHz). These low-frequency modes provide data of exceptional quality, since the width of the mode peaks is much smaller than the rotational splitting, and hence it is much easier to separate the rotational splittings from the effects caused by the finite lifetime and the stochastic excitation of the modes. We have also implemented a new inversion methodology that allows us to infer the rotation rate of the radiative interior from mode sets that span l = 1 to 25. Our results are compatible with the Sun rotating like a rigid solid in most of the radiative zone, and slowing down in the core (r/R⊙ < 0.2). A resolution analysis of the inversion was carried out for the solar rotation inverse problem. This analysis effectively establishes a direct relationship between the mode set included in the inversion and the sensitivity and information content of the resulting inferences. We show that such an approach allows us to determine the effect of adding low-frequency and low-degree p-modes, high-frequency and low-degree p-modes, and some g-modes on the derived rotation rate in the solar radiative zone, and in particular the solar core. We conclude that the level of uncertainty that is needed to infer the dynamical conditions in the core when only p-modes are included is unlikely to be reached in the near future, and hence sustained efforts are needed toward the detection and characterization of g-modes. Title: YAOPBM - yet another peak bagging method Authors: Korzennik, S. G. Bibcode: 2008AN....329..453K Altcode: I present and discuss the fitting methodology I developed for very-long time series (2088-day-long). This new method was first used to fit low degree modes, ℓ ≤25. That time series was also sub-divided in somewhat shorter segments (728-day-long) and also fitted for these low degrees, in order to measure changes with the solar activity level. I have recently extended the fitting in several ``directions'': 1) to substantially higher degrees (ℓ ≤125), 2) to shorter time series (364- and 182-day-long), and, 3) to additional 728-day-long segments, covering now some 10 years of observations. I present and discuss issues related to this expansion, namely problems at low frequencies affecting the f and p_1 modes, and the inadequacy of the leakage matrix at higher degrees. I also present some of the characteristics of the observed temporal changes in the resulting frequencies. Title: Detection and temporal coherence of p-modes below 1.4 mHz Authors: Eff-Darwich, A.; Régulo, C.; Korzennik, S. G.; Pérez Hernández, F.; Roca Cortés, T. Bibcode: 2008AN....329..470E Altcode: Data collected recently by the helioseismic experiments aboard the SOHO spacecraft have allowed the detection of low degree p-modes with increasingly lower order n. In particular, the GOLF experiment is currently able to unambiguously identify low degree modes with frequencies as low as 1.3 mHz. The detection of p-modes with very low frequency ({i.e.}, low n), is difficult due to the low signal-to-noise ratio in this spectral region and its contamination by solar signals that are not of acoustic origin. To address this problem without using any theoretical a priory, we propose a methodology that relies only on the inversion of observed values to define a spectral window for the expected locations of these low frequency modes. The application of this method to 2920-day-long GOLF observations is presented and its results discussed. Title: Analysis of MDI high-degree solar-p mode parameters Authors: Rabello-Soares, M.; Korzennik, S.; Schou, J. Bibcode: 2008AGUSMSP21A..03R Altcode: We present a detailed analysis of solar acoustic mode parameters for modes with degree up to 900. They were obtained by applying spherical harmonic decomposition to full-disk solar images observed by the Michelson Doppler Imager (MDI) on board the Solar and Heliospheric Observatory (SOHO) spacecraft. We have analyzed seven observational periods (2-3 months long) from 1999 to 2005. A physically motivated model including a complete leakage matrix was used to recover the actual high-degree mode characteristics. Title: Variations of the solar acoustic high-degree mode frequencies over solar cycle 23 Authors: Rabello-Soares, M. C.; Korzennik, Sylvain G.; Schou, J. Bibcode: 2008AdSpR..41..861R Altcode: 2007arXiv0712.3608R Using full-disk observations obtained with the Michelson Doppler Imager (MDI) on board the Solar and Heliospheric Observatory (SOHO) spacecraft, we present variations of the solar acoustic mode frequencies caused by the solar activity cycle. High-degree (100 < ℓ < 900) solar acoustic modes were analyzed using global helioseismology analysis techniques over most of solar cycle 23. We followed the methodology described in details in [Korzennik, S.G., Rabello-Soares, M.C., Schou, J. On the determination of Michelson Doppler Imager high-degree mode frequencies. ApJ 602, 481 515, 2004] to infer unbiased estimates of high-degree mode parameters ([see also Rabello-Soares, M.C., Korzennik, S.G., Schou, J. High-degree mode frequencies: changes with solar cycle. ESA SP-624, 2006]). We have removed most of the known instrumental and observational effects that affect specifically high-degree modes. We show that the high-degree changes are in good agreement with the medium-degree results, except for years when the instrument was highly defocused. We analyzed and discuss the effect of defocusing on high-degree estimation. Our results for high-degree modes confirm that the frequency shift scaled by the relative mode inertia is a function of frequency and it is independent of degree. Title: Current status of asteroseismology Authors: Korzennik, Sylvain G. Bibcode: 2008AdSpR..41..897K Altcode: Asteroseismology, the extension of helioseismology to stars solar-alike or not has been an exciting and active field of research for about two decades. While over that period helioseismology has had great success in revealing the solar structure and its dynamics, progress in asteroseismology has been hampered by the observational challenge to carry out, primarily from the ground, high precision measurements on unresolved objects with a substantially lower flux. Over the past years, the field has seen a new golden age, primarily driven by observational advances and opportunities. With the June 2003 launch of the MOST spacecraft and the highly anticipated December 2006 launch of the COROT mission, we have truly entered the space-based observational era of asteroseismology. The ambitious vision mission like the Stellar Imager might even one day allow us to spatially resolve oscillations on not too distant stars. At the same time ground-based observations have recently seen a quantum leap in precision thanks to the synergy between asteroseismology and exo-planet detection which both rely primarily on precise radial velocity techniques. The diagnostic potential of asteroseismology is clearly demonstrated by the wealth of inferences collected from helioseismology. Nevertheless the current status of observations, their interpretations and their implications for our models remain hotly debated subjects. I review the status of the field, with an emphasis on solar-like targets, while incorporating my own healthy scepticism and observational bias. Title: Study of High-Performance Coronagraphic Techniques Authors: Tolls, Volker; Aziz, M. J.; Gonsalves, R. A.; Korzennik, S. G.; Labeyrie, A.; Lyon, R. G.; Melnick, G. J.; Somerstein, S.; Vasudevan, G.; Woodruff, R. A. Bibcode: 2007AAS...20925508T Altcode: 2007BAAS...39..278T We will provide a progress report about our study of high-performance coronagraphic techniques. At SAO we have set up a testbed to test coronagraphic masks and to demonstrate Labeyrie's multi-step speckle reduction technique. This technique expands the general concept of a coronagraph by incorporating a speckle corrector (phase or amplitude) and second occulter for speckle light suppression. The testbed consists of a coronagraph with high precision optics (2 inch spherical mirrors with lambda/1000 surface quality), lasers simulating the host star and the planet, and a single Labeyrie correction stage with a MEMS deformable mirror (DM) for the phase correction. The correction function is derived from images taken in- and slightly out-of-focus using phase diversity. The testbed is operational awaiting coronagraphic masks. The testbed control software for operating the CCD camera, the translation stage that moves the camera in- and out-of-focus, the wavefront recovery (phase diversity) module, and DM control is under development.

We are also developing coronagraphic masks in collaboration with Harvard University and Lockheed Martin Corp. (LMCO). The development at Harvard utilizes a focused ion beam system to mill masks out of absorber material and the LMCO approach uses patterns of dots to achieve the desired mask performance. We will present results of both investigations including test results from the first generation of LMCO masks obtained with our high-precision mask scanner.

This work was supported by NASA through grant NNG04GC57G, through SAO IR&D funding, and by Harvard University through the Research Experience for Undergraduate Program of Harvard's Materials Science and Engineering Center. Central facilities were provided by Harvard's Center for Nanoscale Systems. Title: High-degree Mode Frequencies Using Global Helioseismology Analysis Of MDI Observations And Their Variation With Solar Cycle. Authors: Rabello-Soares, M. Cristina; Korzennik, S. G.; Schou, J. Bibcode: 2007AAS...210.2215R Altcode: 2007BAAS...39..126R Using full-disk observations obtained with the Michelson Doppler Imager (MDI) on board the Solar and Heliospheric Observatory (SOHO) spacecraft, we present solar acoustic mode frequencies and their rotational splitting coefficients for modes with degree up to 900 determined using global helioseismology analysis. Most of the known instrumental and observational effects that affect specifically the high-degree modes have been removed.

The structural and dynamical properties of the near-surface layers of the Sun was analyzed through the study of: (a) the difference between the observed and theoretical frequencies; and (b) the solar rotation at different latitudes estimated using a simple analytical method.

We also present variations of the mode frequencies resulting from solar activity over most of solar cycle 23. We have studied the correlation of medium and high degree modes with four different solar indices. Our results confirm that the frequency shift scaled by the relative mode inertia is a function of frequency alone and follows a simple power law. Title: The cookie cutter test for time-distance tomography of active regions Authors: Korzennik, S. G. Bibcode: 2006ESASP.624E..60K Altcode: 2006soho...18E..60K No abstract at ADS Title: High-degree mode frequencies: changes with solar cycle Authors: Rabello-Soares, M. C.; Korzennik, S. G.; Schou, J. Bibcode: 2006ESASP.624E..71R Altcode: 2006soho...18E..71R No abstract at ADS Title: On the direct determination of sensitivity, resolution and information content of helioseismic data application to the inversion of the solar core rotation rate Authors: Eff-Darwich, A.; Korzennik, S. G.; Jiménez-Reyes, S. J.; García, R. A. Bibcode: 2006ESASP.624E..84E Altcode: 2006soho...18E..84E No abstract at ADS Title: A Keck HIRES Doppler Search for Planets Orbiting Metal-Poor Dwarfs. I. Testing Giant Planet Formation and Migration Scenarios Authors: Sozzetti, Alessandro; Torres, Guillermo; Latham, David W.; Carney, Bruce W.; Stefanik, Robert P.; Boss, Alan P.; Laird, John B.; Korzennik, Sylvain G. Bibcode: 2006ApJ...649..428S Altcode: 2006astro.ph..5670S We describe a high-precision Doppler search for giant planets orbiting a well-defined sample of metal-poor dwarfs in the field. This experiment constitutes a fundamental test of theoretical predictions, which will help discriminate between proposed giant planet formation and migration models. We present details of the survey, as well as an overall assessment of the quality of our measurements, making use of the results for stars that show no significant velocity variation. Title: The determination of global high-degree solar p-mode parameters: challenges and new results Authors: Rabello-Soares, M. C.; Korzennik, S. G.; Schou, J. Bibcode: 2006IAUJD..17E...7R Altcode: We review the challenges of estimating unbiased mode parameters for global high-degree solar acoustic modes (100 < ℓ < 1000), with emphasis on the importance of knowing the instrumental characteristics and how they affect mode parameters determination. We present new estimates of the global high-degree mode parameters resulting from incorporating our best knowledge of the MDI instrument on board SOHO and we also present their dependence with the solar cycle. Title: Study of coronagraphic techniques Authors: Tolls, Volker; Aziz, Michael; Gonsalves, Robert A.; Korzennik, Sylvain; Labeyrie, Antoine; Lyon, Richard; Melnick, Gary; Schlitz, Ruth; Somerstein, Steve; Vasudevan, Gopal; Woodruff, Robert Bibcode: 2006SPIE.6265E..3KT Altcode: 2006SPIE.6265E.107T Smithsonian Astrophysical Observatory (SAO) has set up a program to study coronagraphic techniques. The program consists of the development of new fabrication methods of occulter masks, characterization of the manufactured masks, and application of the masks to study speckle reduction technique. Our occulter mask fabrication development utilizes a focused ion beam system to directly shape mask profiles from absorber material. Initial milling trials show that we can shape nearly Gaussian-shaped mask profiles. Part of this development is the characterization of absorber materials, poly(methyl methacrylate) doped with light-stable chromophores. For the characterization of the masks we have built a mask scanner enabling us to scan the transmission function of occulter masks. The real mask transmission profile is retrieved applying the maximum entropy method to deconvolve the mask transmission function from the beam profile of the test laser. Finally, our test bed for studying coronagraphic techniques is nearing completion. The optical setup is currently configured as a classical coronagraph and can easily be re-configured for studying speckle reduction techniques. The development of the test bed control software is under way. This paper we will give an update of the status of the individual program elements. Title: Changes Of The Solar Acoustic High-degree Mode Frequencies Over The Solar Cycle Authors: Korzennik, Sylvain G.; Rabello-Soares, M. C.; Schou, J. Bibcode: 2006SPD....37.0508K Altcode: 2006BAAS...38..224K Using full-disk observations obtained with the Michelson Doppler Imager (MDI) on board the Solar and Heliospheric Observatory (SOHO) spacecraft, we present frequency and frequency splitting variations of high-degree (100 < l < 1000) solar acoustic modes over the solar cycle using global helioseismology analysis techniques. Since we analyzed high-degree modes, we focus on properties of the near-surface solar region. We have corrected for most of the known instrumental effects that affect the characterization of high-degree modes using the methodology described in Korzennik et al. (2004) as to estimate unbiased high-degree mode frequencies. Title: Precise Radial Velocities with an Upgraded Advanced Fiber Optic Echelle (AFOE) Authors: Walters, M. A.; Korzennik, S. G.; Nisenson, P.; Henry, G. W. Bibcode: 2006AAS...20721108W Altcode: The Advanced Fiber Optic Echelle (AFOE) has been used to make precise radial velocity (PRV) observations for some 12 years. The AFOE spectrograph was initially designed as a test-bed for PRV techniques for astroseismology and planet detection, and tried to provide both short term and long term stability. The resulting trade-offs between spectral resolution, range, and coverage led to a low efficiency design. In order to optimize PRVs obtained with the iodine cell technique, the spectrograph was recently upgraded, increasing the throughput and spectral coverage while reducing the maximum resolution and range. The instrument was also moved from the 60" Tillinghast telescope at the Fred Lawrence Whipple Observatory, located at Mt. Hopkins (AZ), to the 100" Hooker telescope, located at Mt. Wilson (CA). We describe the instrumental changes required for the spectrograph upgrade as well as those needed to accommodate the 100" telescope.

As a result of the instrumental changes, the data configuration has changed significantly. One would like to be able to combine radial velocities obtained before the upgrade with those obtained after, but one must take care in doing so. We describe the methodology developed to allow us to use all of the PRVs together. We also detail the precision achieved for this technique, along with the inherent precision of the upgraded configuration.

Finally, we present the radial velocities we have obtained for HD 185395 as an interesting example of our studies. This triple system shows large radial velocity variations. We compare the RV variations with observed photometric changes, and present period analyses for both data sets.

This work is funded by NASA/JPL/SIM (subcontract no. 1259554). Title: Study of Coronagraphic Techniques Authors: Tolls, Volker; Aziz, Michael; Gonsalves, Robert A.; Korzennik, Sylvain; Labeyrie, Antoine; Lyon, Richard; Melnick, Gary; Somerstein, Steve; Vasudevan, Gopal; Woodruff, Robert Bibcode: 2006dies.conf..457T Altcode: 2006IAUCo.200..457T SAO has set up a testbed to study coronagraphic techniques, starting with Labeyrie's multi-step speckle reduction technique. This technique expands the general concept of a coronagraph by incorporating a speckle corrector (phase and/or amplitude) in combination with a second occulter for speckle light suppression. The correction function is derived applying the phase diversity method on images taken in focus and slightly out-of-focus. The occulter masks for the testbed will initially be produced lithographically. However, in a parallel program we are studying a new manufacturing method. This method utilizes focussed ion beams and will directly mill the mask shape into absorbing material deposited on a transparent substrate. Title: Variations of the solar acoustic high-degree mode parameters over solar cycle 23 Authors: Rabello-Soares, M. C.; Korzennik, S. G.; Schou, J. Bibcode: 2006cosp...36.2668R Altcode: 2006cosp.meet.2668R The structural and dynamical properties of the Sun as well as the excitation and damping of the solar acoustic modes change with the solar cycle The first two manifest themselves as changes in the acoustic mode frequencies and frequency splittings While the last two are observed as changes in the mode amplitudes and lifetimes Using full-disk observations obtained with the Michelson Doppler Imager MDI on board the Solar and Heliospheric Observatory SOHO spacecraft we present the amplitude width frequency and frequency splitting variations of high-degree 100 l 1000 solar acoustic modes over most of solar cycle 23 using global helioseismology analysis techniques By looking at high-degree modes we focus on the properties of the near-surface solar region Following the methodology described in detail in Korzennik et al 2004 we have removed the known instrumental and observational effects that affect specifically high-degree modes as well as possible to infer unbiased estimates of high-degree mode parameters Title: Study of Coronagraphic Techniques Authors: Tolls, V.; Aziz, M.; Gonsalves, R.; Korzennik, S.; Labeyrie, A.; Lyon, R.; Melnick, G.; Somerstein, S.; Vasudevan, G.; Woodruff, R. Bibcode: 2006amos.confE..16T Altcode: Direct imaging of extra-solar planets is important for determining the properties of individual planets, for studying multi-planet systems, and for observing the spatial structure of debris disks. Obtaining spectra of extra-solar planets enables us to constrain the composition of planetary atmospheres and surfaces, their climates, and their rotation periods. The techniques required to isolate and detect an extra-solar planet next to its host star are quite challenging and require significant improvement. SAO has set up a testbed to study coronagraphic techniques, starting with Labeyrie's multi-step speckle reduction technique.

The testbed consists of a classical coronagraph with high precision optics. A telescope is simulated by a 2 inch spherical mirror with lambda/1000 surface quality. The focal length (1 meter) of this mirror was chosen that spherical aberration can be neglected. A spatially-filtered laser simulates the host star and an optional attenuated second laser simulates the planet. As an additional option, we can incorporate apodizing masks to further improve the performance of the coronagraph. The output signal of the coronagraph is fed into a single Labeyrie correction stage. It consists of a mirror to relay the light onto a 140-element MEMS deformable mirror (DM) for the phase correction. The reflected light is then focused onto a second occulter to block most of the speckle light and finally imaged onto a CCD. The phase correction function and, thus, the drive signal for the DM, is derived from images taken in and slightly out of the focal plane using phase diversity. The expected performance improvement is about one order of magnitude. An advanced concept utilizing phase and amplitude correction promises an even higher degree of speckle light suppression.

In addition, we are using the testbed to characterize occulter masks developed in collaboration with Harvard University and Lockheed Martin Corp. At Harvard University we are developing a method to shape occulter masks out of dye-doped PMMA using a focused ion beam (FIB) system. Using dye-doped PMMA should enable us to manufacture masks working at any wavelength from the visible to the near-infrared. It should also be possible to manufacture masks for the IR if a suitable mask material can be found. In order to test the absorption profile of these masks, we are developing a high-precision mask scanner. This work is supported by NASA through grant NNG04GC57G, SAO IR&D funding, NSF REU program and Harvard College. Title: Current status of asteroseismology Authors: Korzennik, S. Bibcode: 2006cosp...36.2553K Altcode: 2006cosp.meet.2553K Asteroseismology the extension of Helioseismology to stars - solar-alike or not - has been an exciting and active filed of research for about two decades While over that period helioseismology has had great success in revealing the solar structure and it dynamics progress in asteroseismology has been hampered by the observational challenge to carry out from the ground high precision measurements on unresolved objects with a substantial lower flux Over the past years the field has seen a new golden age primarily driven by new observational advances and opportunities On one hand with the launch of the MOST spacecraft and the selection of the COROT mission we have truly entered the space-based observational era of asteroseismology Moreover the ambitious vision mission like the Stellar Imager might even one day allow us to spatially resolve oscillations on not too distant stars On the other hand ground-based observations have recently seen a quantum leap in precision -- thanks in some way to the synergy of precise radial velocity techniques aimed at exo-planet detection The wonderful diagnostic potential of asteroseismology can clearly be derived from the wealth of inferences collected from helioseismology Nevertheless the current status of observations their interpretations and their implication on our models remain hotly debated subjects I will review the status of the field with an emphasis on solar-like targets while incorporating my own healthy scepticism and observational bias Title: Study of Coronagraphic Techniques Authors: Tolls, V.; Aziz, M. J.; Gonsalves, R. A.; Korzennik, S. G.; Labeyrie, A.; Lyon, R. G.; Melnick, G. J.; Somerstein, S.; Vasudevan, G.; Woodruff, R. A. Bibcode: 2005AAS...20719105T Altcode: 2005BAAS...37.1487T Direct imaging of extra-solar planets is important for determining the properties of individual planets and to study multi-planet systems. Obtaining spectra of extra-solar planets enables us to constrain the composition of planetary atmospheres and surfaces, their climates, and their rotation periods. The techniques required to isolate and detect an extra-solar planet next to its host star are quite challenging and require significant improvement. SAO has set up a testbed to study coronagraphic techniques, starting with Labeyrie's multi-step speckle reduction technique. This technique expands the general concept of a coronagraph by incorporating a speckle corrector (phase or amplitude) and second occulter for speckle light suppression. The testbed consists of a coronagraph with high precision optics (2 inch spherical mirrors with lambda/1000 surface quality), lasers simulating the host star and the planet, and a single Labeyrie correction stage with a MEMS deformable mirror for the phase correction. The correction function is derived from images taken in and slightly out of the focal using phase diversity. In addition, we are using the testbed for occulter masks developed in collaboration with Harvard University and Lockheed Martin Corp. This testing is also supported by a high-precision mask scanner for mask characterization. This work was supported by NASA through grant NNG04GC57G. Title: Study of high-performance coronagraphic techniques Authors: Tolls, Volker; Aziz, Michael; Gonsalves, Robert A.; Korzennik, Sylvain; Labeyrie, Antoine; Lyon, Richard; Melnick, Gary; Somerstein, Steve; Vasudevan, Gopal; Woodruff, Robert Bibcode: 2005SPIE.5905..494T Altcode: SAO has set up a testbed to study coronagraphic techniques, starting with Labeyrie's multi-step speckle reduction technique. This technique expands the general concept of a coronagraph by incorporating a speckle corrector (phase and/or amplitude) in combination with a second occulter for speckle light suppression. Here we are describing the initial testbed configuration. In addition, the testbed will be used to test a new approach of the phase diversity method to retrieve the speckle phase and amplitude. This method requires measurements of the speckle pattern in the focal plane and slightly out-of-focus. Then we will calculate a phase of the wave from which we can derive a correction function for the speckle corrector. Furthermore we report results from a parallel program which studies new manufacturing methods of soft-edge occulter masks. Masks were manufactured using the spherical caps method. Since the results were not satisfying we also investigated the method of ion beam milling of masks. Here we will present the outline of this method. Masks manufactured with both methods will be fully characterized in our mask tester before their use in the testbed. Title: A Mode-Fitting Methodology Optimized for Very Long Helioseismic Time Series Authors: Korzennik, S. G. Bibcode: 2005ApJ...626..585K Altcode: I describe and present the results of a newly developed fitting methodology optimized for very long time series. The development of this new methodology was motivated by the fact that we now have more than half a decade of nearly uninterrupted observations by the Global Oscillation Network Group (GONG) and the Michelson Doppler Imager (MDI), with fill factors as high as 82.2% and 89.8%, respectively. It was recently prompted by the availability of a 2088 day long time series of spherical harmonic coefficients produced by the MDI team. The fitting procedure uses an optimal sine multitaper spectral estimator, with the number of tapers based on the mode line width, the complete leakage matrix (i.e., horizontal as well as vertical components), and an asymmetric mode profile to fit simultaneously all the azimuthal orders with individually parameterized profiles. This method was applied to 2088 day long time series of MDI and GONG observations, as well as 728 day long subsets, and for spherical harmonic degrees between 1 and 25. The values resulting from these fits are intercompared (MDI vs. GONG) and compared to equivalent estimates from the MDI team and the GONG project. I also compare the results from fitting the 728 day subsets to the result of the 2088 day time series. This comparison shows the well-known change of frequencies with solar activity and how it scales with a nearly constant pattern in frequency and m/l. This comparison also shows some changes in the mode line width and the constancy of the mode asymmetry. Title: New Steps Towards the Unbiased Characterization of High-Degree Mode Frequencies Authors: Rabello-Soares, M. C.; Korzennik, S. G.; Schou, J. Bibcode: 2005AGUSMSP11B..08R Altcode: Bias in the characterization of high-degree mode frequency results from the blending of individual modes into ridges as mode lifetimes get shorter and spatial leaks get closer in frequency at high degrees. To recover the actual underlying mode frequency from fitting the ridge, an accurate model of the amplitude of the peaks that contribute to the ridge power distribution is crucial. Such a model requires that the instrumental characteristics be very well understood and very precisely measured. We here present new results from our continuing effort to estimate unbiased high-degree mode frequencies using full-disk data from the Michelson Doppler Imager (MDI) on the Solar and Heliospheric Observatory (SOHO). The methodology is based on the extensive analysis presented in Korzennik et al (2004) - and will in turn be beneficial to MDI, GONG and eventually HMI. The key improvement on our previous work is the re-decomposition of the images onto spherical harmonic component. This new spatial decomposition incorporates specific MDI instrumental characteristics, like a more accurate plate scale, our best model of the image distortion, the image orientation, etc... These instrumental effects were introduced one at a time and their effect carefully compared to the predictions of our model. As expected, by including these corrections in the spatial decomposition, the residual corrections that must be applied to the ridge frequency are reduced, leading to a less biased frequency estimation. Title: Study of Coronagraphic Techniques Authors: Tolls, V.; Nisenson, P.; Aziz, M. J.; Gonsalves, R. A.; Korzennik, S. G.; Labeyrie, A.; Lyon, R. G.; Melnick, G. J.; Woodruff, R. A. Bibcode: 2004AAS...20517104T Altcode: 2005BAAS...37..376T Direct imaging of extra-solar planets is important for determining the properties of individual planets and to study multi-planet systems. Obtaining spectra of extra-solar planets enables us to constrain the composition of planetary atmospheres and surfaces, their climates, and their rotation periods. The techniques required to isolate and detect an extra-solar planet next to its host star are quite challenging and require significant improvement. SAO is setting up a testbed to study coronagraphic techniques, starting with Labeyrie's multi-step speckle reduction technique. This technique incorporates a speckle phase corrector and second occulter for speckle light suppression. The goal is to study this technique in the testbed for its application in coronagraphic cameras. In addition, the testbed will be used to characterize soft-edge occulters. Simulations of soft-edge occulters with a Gaussian absorption profile show a promising reduction of the flux in the core of the point spread function in coronagraphs. We expect this to lead to a reduction in the inner working distance and to an increase in contrast ratio compared to a Lyot coronagraph. The occulters for the tests will be developed in Harvard's Department of Engineering and Applied Sciences and by Lockheed-Martin Corp. This poster will present the setup of SAO's testbed, simulations for all developments, and first test results. Title: PCA Inversions for the Rotation of the Solar Radiative Interior Authors: Eff-Darwich, A.; Korzennik, S. G.; Jiménez-Reyes, S.; García, R. A. Bibcode: 2004ESASP.559..420E Altcode: 2004soho...14..420E No abstract at ADS Title: a Mode Fitting Methodology Optimized for Very Long Time Series Authors: Korzennik, S. G. Bibcode: 2004ESASP.559..524K Altcode: 2004soho...14..524K; 2004astro.ph..6470K I describe and present the results of a newly developed fitting methodology optimized for very long time series. The development of this new methodology was motivated by the fact that we now have more than half a decade of nearly uninterrupted observations by GONG and MDI, with fill factors as high as 89.8% and 82.2% respectively. It was recently prompted by the availability of a 2088-day-long time series of spherical harmonic coefficients produced by the MDI team. The fitting procedure uses an optimal sine-multi-taper spectral estimator -- whith the number of tapers based on the mode linewidth, the complete leakage matrix (i.e., horizontal as well as vertical components), and an asymmetric mode profile to fit simultaneously all the azimuthal orders with individually parametrized profiles. This method was applied to 2088-day-long time series of MDI and GONG observations, as well as 728-day-long subsets, and for spherical harmonic degrees between 1 and 25. The values resulting from these fits are inter-compared (MDI versus GONG) and compared to equivalent estimates from the MDI team and the GONG project. I also compare the results from fitting the 728-day-long subsets to the result of the 2088-day-long time series. This comparison shows the well known change of frequencies with solar activity -- and how it scales with a nearly constant pattern in frequency and m/l. This comparison also shows some changes in the mode linewidth and the constancy of the mode asymmetry. Title: On the Spatial Dependence of Low-Degree Solar p-Mode Frequency Shifts from Full-Disk and Resolved-Sun Observations Authors: Jiménez-Reyes, S. J.; García, R. A.; Chaplin, W. J.; Korzennik, S. G. Bibcode: 2004ApJ...610L..65J Altcode: We have analyzed low angular degree (low-l) solar p-mode frequency shifts extracted from two types of observations, both made by instruments on board the ESA/NASA Solar and Heliospheric Observatory satellite during a period that covers the rising phase of activity, cycle 23 (1995-2002). The first are full-disk (Sun-as-a-star) averages made in Doppler velocity by the Global Oscillations at Low Frequency spectrophotometer; the second are Doppler velocity observations made with high spatial resolution by the Michelson Doppler Imager. We compare the eigenfrequency shifts from both sets of data and find that they are consistent at the level of precision of the observations. Furthermore, the sizes of the shifts uncovered for different mode components are found to scale in proportion to the corresponding spherical harmonic components of the observed line-of-sight surface magnetic field, with the sectoral mode components showing (as expected) the largest shifts. Title: About the rotation of the solar radiative interior Authors: García, R. A.; Corbard, T.; Chaplin, W. J.; Couvidat, S.; Eff-Darwich, A.; Jiménez-Reyes, S. J.; Korzennik, S. G.; Ballot, J.; Boumier, P.; Fossat, E.; Henney, C. J.; Howe, R.; Lazrek, M.; Lochard, J.; Pallé, P. L.; Turck-Chièze, S. Bibcode: 2004SoPh..220..269G Altcode: In the modern era of helioseismology we have a wealth of high-quality data available, e.g., more than 6 years of data collected by the various instruments on board the SOHO mission, and an even more extensive ground-based set of observations covering a full solar cycle. Thanks to this effort a detailed picture of the internal rotation of the Sun has been constructed. In this paper we present some of the actions that should be done to improve our knowledge of the inner rotation profile discussed during the workshop organized at Saclay on June 2003 on this topic. In particular we will concentrate on the extraction of the rotational frequency splittings of low- and medium-degree modes and their influence on the rotation of deeper layers. Furthermore, for the first time a full set of individual |m|-component rotational splittings is computed for modes ℓ≤4 and 1<ν<2 mHz, opening new studies on the latitudinal dependence of the rotation rate in the radiative interior. It will also be shown that these splittings have the footprints of the differential rotation of the convective zone which can be extremely useful to study the differential rotation of other stars where only these low-degree modes will be available. Title: p-mode frequencies in solar-like stars. I. Procyon A Authors: Martić, M.; Lebrun, J. -C.; Appourchaux, T.; Korzennik, S. G. Bibcode: 2004A&A...418..295M Altcode: 2004astro.ph..3035M As a part of an on-going program to explore the signature of p-modes in solar-like stars by means of high-resolution absorption line spectroscopy, we have studied four stars (α CMi, η Cas A, ζ Her A and β Vir). We present here new results from two-site observations of Procyon A acquired over twelve nights in 1999. Oscillation frequencies for l=1 and 0 (or 2) p-modes are detected in the power spectra of these Doppler shift measurements. A frequency analysis points out the difficulties of the classical asymptotic theory in representing the p-mode spectrum of Procyon A.

Based on observations obtained at the Observatoire de Haute-Provence (CNRS, France) and at the Whipple Observatory (Arizona, USA). Title: On the Determination of Michelson Doppler Imager High-Degree Mode Frequencies Authors: Korzennik, S. G.; Rabello-Soares, M. C.; Schou, J. Bibcode: 2004ApJ...602..481K Altcode: 2002astro.ph..7371K The characteristics of the solar acoustic spectrum are such that mode lifetimes get shorter and spatial leaks get closer in frequency as the degree of a mode increases for a given order. A direct consequence of this property is that individual p-modes are resolved only at low and intermediate degrees and that at high degrees individual modes blend into ridges. Once modes have blended into ridges, the power distribution of the ridge defines the ridge central frequency, and it will mask the true underlying mode frequency. An accurate model of the amplitude of the peaks that contribute to the ridge power distribution is needed to recover the underlying mode frequency from fitting the ridge. We present the results of fitting high-degree power ridges (up to l=900) computed from several 2-3 month long time series of full-disk observations taken with the Michelson Doppler Imager (MDI) on board the Solar and Heliospheric Observatory between 1996 and 1999. We also present a detailed discussion of the modeling of the ridge power distribution, and the contribution of the various observational and instrumental effects on the spatial leakage, in the context of the MDI instrument. We have constructed a physically motivated model (rather than some ad hoc correction scheme) that we believe results in a methodology that can produce an unbiased determination of high-degree modes once the instrumental characteristics are well understood. Finally, we present preliminary estimates of changes in high-degree mode parameters with epoch and thus solar activity level and discuss their significance. These estimates are preliminary because they rely on a simple-if not simplistic-ridge-to-mode correction scheme to account for errors in the plate scale used for the spherical harmonic decomposition. Such a correction scheme produced residual systematics that, as we show, are not always constant with time. These cannot be properly corrected without reprocessing the data back to the level of the spherical harmonic decomposition. Title: Calculating Velocity Shifts Between the Pre- and Post-Upgrade AFOE Data Sets Authors: Miller, J. K.; Korzennik, S. G.; Nisenson, P. Bibcode: 2003AAS...203.1710M Altcode: 2003BAAS...35.1235M We present the results of our efforts to develop a procedure to determine the velocity shifts between the pre- and post-upgrade stellar reference spectra observed with the Advanced Fiber Optic Echelle (AFOE). The AFOE spectrograph was upgraded to increase its efficiency in measuring radial velocities by rearranging the physical set-up of the optical system. While observing roughly the same wavelength range, the post-upgrade spectra have a different ratio of wavelength to pixels and gaps in the data where pieces of the spectrum were not projected onto the CCD. These differences necessitated taking new stellar references of each star system. All velocity measurements for a star are made relative to this reference. However, there is an unknown velocity shift between every pair of new and old stellar reference spectra simply because they were observed on different nights. The differences in the spectra prevent us from recalculating all of the velocities relative to one reference or the other. To overcome this problem, we have been developing a procedure that models the new stellar reference with a parameterized function of the old reference, and the velocity shift is one parameter of the model. We independently model each wavelength range of the new spectrum that overlaps the old spectrum, which gives us twelve measurements of the velocity shift. The spread in these results gives us an idea of the precision of our calculations, and our goal precision is ∼ 1 ms-1.

This work was supported in part by the SAO intern program under NSF grant AST-9731923. Title: The ELODIE survey for northern extra-solar planets. II. A Jovian planet on a long-period orbit around GJ 777 A Authors: Naef, D.; Mayor, M.; Korzennik, S. G.; Queloz, D.; Udry, S.; Nisenson, P.; Noyes, R. W.; Brown, T. M.; Beuzit, J. L.; Perrier, C.; Sivan, J. P. Bibcode: 2003A&A...410.1051N Altcode: 2003astro.ph..6586N We present radial-velocity measurements obtained with the ELODIE and AFOE spectrographs for GJ 777 A (HD 190360), a metal-rich ([Fe/H] = 0.25) nearby (d = 15.9 pc) star in a stellar binary system. A long-period low radial-velocity amplitude variation is detected revealing the presence of a Jovian planetary companion. Some of the orbital elements remain weakly constrained because of the smallness of the signal compared to our instrumental precision. The detailed orbital shape is therefore not well established. We present our best fitted orbital solution: an eccentric (e = 0.48) 10.7-year orbit. The minimum mass of the companion is 1.33 MJup.

Based on observations made with the ELODIE echelle spectrograph mounted on the 1.93-m Telescope at the Observatoire de Haute-Provence (CNRS) and with the AFOE spectrograph mounted on the 1.5-m Telescope at the Fred Lawrence Whipple Observatory (SAO).

The ELODIE and AFOE measurements discussed in this paper are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/410/1051 Title: VizieR Online Data Catalog: ELODIE survey for northern extra-solar planets. II. (Naef+, 2003) Authors: Naef, D.; Mayor, M.; Korzennik, S. G.; Queloz, D.; Udry, S.; Nisenson, P.; Noyes, R. W.; Brown, T. M.; Beuzit, J. L.; Perrier, C.; Sivan, J. P. Bibcode: 2003yCat..34101051N Altcode: Here are the 69 radial-velocity measurements of GJ 777A (HD 190360) used for deriving the orbital solution of this star. These velocities were obtained using the ELODIE echelle spectrograph mounted on the 1.93-m Telescope at Observatoire de Haute-Provence (France) and the AFOE spectrograph mounted on the 1.5-m Telescope at the Fred Lawrence Whipple Observatory (USA).

(1 data file). Title: On the characterization of high-degree modes: a lesson from MDI Authors: Korzennik, Sylvain G.; Rabello-Soares, Cristina; Schou, Jesper Bibcode: 2003ESASP.517..145K Altcode: 2003soho...12..145K High degree power ridges (up to l = 900) were computed and fitted for several two to three-month-long time-series of full-disk observations taken with the Michelson Doppler Imager (MDI) on-board the Solar and Heliospheric Observatory between 1996 and 1999. A detailed discussion of the modeling of the ridge power distribution, and the contribution of the various observational and instrumental effects on the spatial leakage, in the context of the MDI instrument, are presented. The result of this work is a better understanding of the problems associated with the characterization of high degree modes. We present the instrumental and observational requirements needed to achieve a determination of high degree mode frequencies whose residual systematic errors associated with the accuracy of the ridge to mode correction scheme are smaller than the uncertainty of the fitting itself. Title: A new upper limit to the temporal variation of the rotation rate of the tachocline between 1994 and 2002 Authors: Eff-Darwich, A.; Korzennik, S. G. Bibcode: 2003ESASP.517..267E Altcode: 2003soho...12..267E We have inverted most of the available rotational frequency splittings at intermediate degrees. Namely, LOWL data from 1994 to 2000, GONG data from 1995 to 2001, and, MDI data from 1996 to 2002. Our purpose was to look for any temporal variation of the tachocline and its relation to the solar activity cycle. However, we did not find any significant change compatible with the three data sets. From our analysis, we estimated an upper limit on the temporal variation of Ω/2π of 3 nHz. This value is commensurable with the sensitivity of the present observational data to changes in the rotation rate of the tachocline. Title: Analysis of rotational frequency splittings sensitive to the rotation rate of the solar core Authors: García, R. A.; Eff-Darwich, A.; Korzennik, S. G.; Couvidat, S.; Henney, C. J.; Turck-Chièze, S. Bibcode: 2003ESASP.517..271G Altcode: 2003soho...12..271G Updated solar frequency splitting measurements suggest a slight decrease of the rotation rate below 0.25 Rsolar and, albeit preliminary, rule out a core rotating faster than the upper radiative zone. The estimates of the rotation rate of the deep solar layers are based on new rotational frequency splittings computed using data from the GOLF and MDI instruments on board SoHO. Such results, provided they are confirmed after further analysis, give additional insight into the dynamics of the solar core. Title: The Extrasolar Planet Imager (ESPI) Authors: Nisenson, P.; Melnick, G. J.; Geary, J.; Holman, M.; Korzennik, S. G.; Noyes, R. W.; Papaliolios, C.; Sasselov, D. D.; Fischer, D.; Gezari, D.; Lyon, R. G.; Gonsalves, R.; Hardesty, C.; Harwit, M.; Marley, M. S.; Neufeld, D. A.; Ridgway, S. T. Bibcode: 2003ASPC..294..633N Altcode: 2002astro.ph.10046N ESPI has been proposed for direct imaging and spectral analysis of giant planets orbiting solar-type stars. ESPI extends the concept suggested by Nisenson and Papaliolios (2001) for a square aperture apodized telescope that has sufficient dynamic range to directly detect extrasolar planets. With a 1.5-meter square mirror, ESPI can deliver high dynamic range imagery as close as 0.3 arcseconds to bright sources, permitting a sensitive search for extrasolar planets around nearby stars and a study of their characteristics in reflected light. Title: An Upper Limit on the Temporal Variations of the Solar Interior Stratification Authors: Eff-Darwich, A.; Korzennik, S. G.; Jiménez-Reyes, S. J.; Pérez Hernández, F. Bibcode: 2002ApJ...580..574E Altcode: 2002astro.ph..7402E We have analyzed changes in the acoustic oscillation eigenfrequencies measured over the past 7 years by the GONG, MDI, and LOWL instruments. The observations span the period from 1994 to 2001 that corresponds to half a solar cycle, from minimum to maximum solar activity. These data were inverted to look for a signature of the activity cycle on the solar stratification. A one-dimensional structure inversion was carried out to map the temporal variation of the radial distribution of the sound speed at the boundary between the radiative and convective zones. Such variation could indicate the presence of a toroidal magnetic field anchored in this region. We found no systematic variation with time of the stratification at the base of the convection zone. However, we can set an upper limit to any fractional change of the sound speed at the level of 3×10-5. Title: Inversion of the Internal Solar Rotation Rate Authors: Eff-Darwich, A.; Korzennik, S. G.; Jiménez-Reyes, S. J. Bibcode: 2002ApJ...573..857E Altcode: Accurate determination of the rotation rate in the inner radiative zone (0.2<r/Rsolar<0.5) of the Sun from helioseismic observations requires rotational frequency splittings of exceptional quality. Indeed, only the very low degree modes are sensitive to the dynamics of the deep interior. Low- and intermediate-degree splittings have been estimated from a variety of instruments and different data analysis procedures. Therefore, it is not surprising that these determinations present significant differences. We have attempted to build consistent data sets to constrain the dynamics of the solar core, excluding features in the data that are not common to all sets as well as excluding modes for frequencies for which such measurements are not reliable. Our inferences of the solar internal rotation profile were obtained from a full two-dimensional numerical inversion based on the optimal mesh distribution methodology, a variant of the regularized least-squares technique. Our results show that the radiative zone rotates at a rate of approximately 435 nHz, slowing down slightly in the core (r/Rsolar<0.35). We also did not find any significant angular differential rotation below the base of the convective zone (r/Rsolar~0.7). We can rule out any departure of the rotation rate in the solar deep interior, 0.2<r/Rsolar<0.4, by more than 20% of the surface rotation rate at midlatitude. This result is in clear disagreement with the theoretical hydrodynamical models that expect a much faster rotation rate in the solar core, some 10-50 times faster than the surface rate. Title: The Extra-Solar Planet Imager (ESPI): A Proposed MIDEX Mission Authors: Melnick, G. J.; Fischer, D.; Geary, J. C.; Gezari, D. Y.; Hardesty, C.; Harwit, M.; Holman, M.; Korzennik, S. G.; Lyon, R. G.; Marley, M. S.; McElroy, M. B.; Neufeld, D. A.; Nisenson, P.; Noyes, R. W.; Papaliolios, C.; Ridgway, S. T.; Sasselov, D. D. Bibcode: 2001AAS...199.0910M Altcode: 2002BAAS...34..559M ESPI is a project that has been proposed as a NASA MIDEX for direct imaging and spectral analysis of giant planets orbiting solar-type stars. ESPI extends the concept suggested by Nisenson and Papaliolios (2001) for a square aperture apodized telescope that has sufficient dynamic range to directly detect exo-planets. ESPI can deliver high dynamic range imagery as close as 0.32 arcseconds to bright sources, permitting a sensitive search for exoplanets around nearby stars and a study of their characteristics in reflected light. It also permits unique observations of many Galactic, extragalactic and cosmological sources. The ESPI Survey will be conducted with a square 1.5 x 1.5-meter telescope mirror, operated in conjunction with a Jacquinot apodization mask that has a throughput of more than 30 percent. The system is capable of detecting Jupiter-like planets in relatively long-period orbits around as many as 160 to 175 stars with a signal-to-noise ratio greater than 5. In addition to the survey, ESPI will also study a few of the brightest discovered planets spectroscopically and spectrophotometrically to distinguish ice giants like Uranus and Neptune from gas giants like Jupiter and Saturn, and to determine whether super-Earth and super-Venus planets exist. Nisenson, P. and Papaliolios, C. 2001, ApJ, 548, L 201. Title: Energy Distribution of Solar Oscillation Modes Inferred from Space-Based Measurements Authors: Woodard, M. F.; Korzennik, S. G.; Rabello-Soares, C.; Kumar, P.; Tarbell, T. D.; Acton, S. Bibcode: 2001AGUSM..SP21C05W Altcode: We have measured the energy distribution of solar p- and f-mode oscillations of angular degree and temporal frequency in the range 100<l<800 and 2<ν (mHz)<4 using helioseismology data from the SOI/MDI instrument on the SOHO satellite. At temporal frequency ν ≈ 3 mHz, the surface velocity power per oscillation mode increases slightly with angular degree between l = 100 and l=200, but decreases rather steeply with l above l=200, in approximate agreement with earlier findings from ground-based measurements. From this we infer that the time-averaged energy per mode, which is theoretically related to the modal surface velocity power, decreases steeply with l at fixed frequency, over the entire observed l range. Specifically, at ν =3.1 mHz the energy per mode drops by a factor of ≈ 10 between l=150 and l=650, a circumstance not quantitatively understood at present. This research was supported by NASA and Stanford University. Title: Time-Distance Inversions: Potential and Limitations Authors: Korzennik, S. G.; Eff-Darwich, A. Bibcode: 2001AGUSM..SP31A20K Altcode: Time-distance analysis is emerging as a powerful diagnostic tool in local helioseismology. By directly measuring propagation times of wave packets between selected locations at the surface of the sun, and their variations over specific areas, a directed diagnostic of the physical properties of the region below these areas can be achieved. We present and discuss inversion methodologies specific to time-distance analysis. These have been optimized for sparse matrices, and include error-bar computation as well as resolution kernel estimation. Our inversion methodology for velocity flow allow us to impose a mass-conservation constrain. We show the diagnostic potential of time-distance inversion and its limitation with various simulations. We illustrate the inversion resolving power potential and discuss the trade-off between resolution and error magnification, including the effect of imposing mass-conservation for velocity flow inferences. We also show inferences from actual observations obtained with the MDI experiment on board the SOHO spacecraft. Title: Energy Distribution of Solar Oscillation Modes Inferred from Space-based Measurements Authors: Woodard, M. F.; Korzennik, S. G.; Rabello-Soares, M. C.; Kumar, P.; Tarbell, T. D.; Acton, S. Bibcode: 2001ApJ...548L.103W Altcode: We have measured the energy distribution of solar p- and f-mode oscillations of angular degree and temporal frequency in the range 100<l<800 and 2<ν(mHz)<4 using helioseismology data from the Solar Oscillations Investigation-Michelson Doppler Imager instrument on the Solar and Heliospheric Observatory satellite. At temporal frequency ν~3 mHz, the surface velocity power per oscillation mode increases slightly with angular degree between l=100 and l=200 but decreases rather steeply with l above l=200, in approximate agreement with earlier findings from ground-based measurements. From this we infer that the time-averaged energy per mode, which is theoretically related to the modal surface velocity power, decreases steeply with l, at fixed frequency, over the entire observed l-range. Specifically, at ν=3.1 mHz, the energy per mode drops by a factor of ~10 between l=150 and l=650, a circumstance not quantitatively understood at present. Title: Interdependence of the basis functions of the solar stratification inversion problem Authors: Eff-Darwich, A.; Pérez-Hernández, F.; Korzennik, S. G. Bibcode: 2001ESASP.464..503E Altcode: 2001soho...10..503E In helioseismic inversions, the number of independent pieces of information that a mode set contains is much less than the actual number of modes. This is due in part to the similarity between the basis functions that define the inverse problem, the kernels, while the observational errors also contribute to the loss of independent information. We have devised a strategy to assess the amount of independent and accessible information contained in a given mode set. It consists in calculating the number of linearly independent data, that is the number of modes that cannot be obtained as linear combinations of the others. We have restricted our analysis to the solar stratification inverse problem. It turns out that within the present observational errors, only a small amount of modes are linearly independent. Indeed, if we use a SOI/MDI data set of 1560 modes, only 117 were independent. Although this result might appear discouraging indicating an apparent substantial loss of useful information, it also allow us to reparameterize the data set before the inversion is carried out. Such reparameterization considerably reduce the computation burden of such inversion. Title: Rotation of the solar interior: compatibility of different helioseismic data sets Authors: Eff-Darwich, A.; Thiery, S.; Jiménez-Reyes, S.; Korzennik, S. G.; Pérez-Hernández, F. Bibcode: 2001ESASP.464..507E Altcode: 2001soho...10..507E Accurate determination of the rotation rate in the inner radiative zone (0.2 < r/Rsolar < 0.5) of the sun from helioseismic observations requires rotational frequency splittings of exceptional quality. Indeed, only low degree modes are sensitive to the dynamics of the deep interior. Low and intermediate degree splittings have been estimated from a variety of instruments as well as different data analysis procedures. It is therefore not surprising that these determinations present significant differences. We present a study of the three more common data sets used to infer the solar rotation rate, namely LOWL, GONG and SOI/MDI. Our purpose is to find the common features present in the three sets, in order to build a robust determination of the rotation rate in the solar interior. We also have analyzed the effect of using rotational splittings estimated by fitting an asymmetric profile rather than a symmetric Lorentzian as a model for the limit spectrum. Title: The determination of MDI high-degree mode frequencies Authors: Rabello-Soares, M. C.; Korzennik, S. G.; Schou, J. Bibcode: 2001ESASP.464..129R Altcode: 2001soho...10..129R As mode lifetimes get shorter and spatial leaks get closer in frequency, individual p-modes can only be resolved up to some degree l (around 150). At higher degrees, individual modes blend into ridges and the power distribution of the ridge masks the true underlying mode frequency. To recover the underlying mode frequency from fitting the ridge, an accurate model of the amplitude of the peaks that contribute to the ridge power distribution is needed. Using full-disk data from the Michelson Doppler Imager data on the Solar and Heliospheric Observatory, we present and discuss the differences between the observations and the spatial leakage calculation (including the horizontal component) and estimate the horizontal-to-vertical displacement ratio for medium-degree modes using sectoral modes for different observational periods. We show how time variations in the instrument calibration affect the spatial leakage and discuss their importance in the spatial leakage calculation. By constructing a physically motivated model (rather than some ad hoc correction scheme) can we hope to produce an unbiased determination of the high-degree modes in the near future. Title: Sensitivity of oscillation frequencies to temporal variations in the tachocline region Authors: Eff-Darwich, A.; Pérez Hernández, F.; Korzennik, S. G. Bibcode: 2001ESASP.464..289E Altcode: 2001soho...10..289E We have analyzed the differences in the oscillation eigenfrequencies measured over four years of GONG, SOI/MDI and LOWL observations (1996 to 1999). We have inverted these data to look for signatures of the solar activity cycle on the stratification. A one-dimensional structure inversion code was used to study temporal variations of the radial distribution of the sound speed at the boundary between the radiative and convective zones. Such variations could be an indication of the presence of a toroidal magnetic field anchored in this region. We have not found systematic variations of the stratification at the base of the convection zone. However we set an upper limit to fractional variations of the sound speed of approximately 4×10-5. Title: On the diagnostic potential of time-distance helioseismology Authors: Korzennik, Sylvain G. Bibcode: 2001ESASP.464..149K Altcode: 2001soho...10..149K Time-distance analysis has proven to be a powerful and intuitively self evident approach for local helioseismology. By directly measuring propagation times of wave packets between selected locations at the surface, and their variations over a specific area of the sun, a directed diagnostic of the physical properties of that region can be achieved. The empirical approach taken by most investigators appears to be robust and has produced enticing results. But surprisingly, the theoretical framework for time-distance seismology remains sketchy. At the same time, rigorous inversion methodologies need to be further developed and validated; and, as in any inverse problem, the topology of the underlying anihilator must be well understood to adequately interpret the inferred properties. Using simulated observables and focusing on the inference of the velocity flow, I illustrate the diagnostic potential of time-distance inversion and its limitation with simple and realistic simulations. I also present inversions based on actual observations obtained with the MDI instrument on board SOHO. Title: A self-consistent procedure to detect low-l low-n solar p-modes Authors: Eff-Darwich, A.; Régulo, C.; Roca Cortés, T.; Pallé, P. L.; Korzennik, S. G. Bibcode: 2001ESASP.464..511E Altcode: 2001soho...10..511E Recent data colleted by the helioseismic experiments aboard SOHO have allowed the detection of low degree p-modes with lower and lower order, n. In particular, the GOLF experiment is currently able to identify unambiguously modes as low as n = 8 for l = 0, and l = 1 (e.g., ≍1.3 mHz). To detect p-modes with lower n (hence lower frequeny), where the signal-to-noise ratio gets small, one needs some guidance. Several groups use theoretical predictions from a standard solar model as a guide. But using theoretical predictions has the potential to bias the mode identification and in turn produce modes that confirm the features of the model rather than the properties of the actual sun. To alleviate this, we propose an alternative methodology based on peak fitting techniques and helioseismic data inversion procedures. This method allow us to reject many peaks from the spectrum by using the prediction capability of the inversion. We describe the method and show resuls from its application to current GOLF spectra. Title: Response of the radial stratification at the base of the convection zone to the activity cycle Authors: Eff-Darwich, Antonio; Korzennik, Sylvain G. Bibcode: 2000SoPh..193..365E Altcode: We have analyzed the differences in the oscillation eigenfrequencies measured over more than two years of GONG observations (December 1995-April 1998) and SOI/MDI observations (May 1996-July 1998). We have inverted these data to look for signatures of the solar activity cycle on the stratification. A one-dimensional (radial) structure inversion code was used to study temporal variations of the sound speed distribution at the boundary between the radiative and convective zones. Such variations could be an indication of the presence of a toroidal magnetic field anchored in this region. Title: A High-Eccentricity Low-Mass Companion to HD 89744 Authors: Korzennik, Sylvain G.; Brown, Timothy M.; Fischer, Debra A.; Nisenson, Peter; Noyes, Robert W. Bibcode: 2000ApJ...533L.147K Altcode: 2000astro.ph..3045K HD 89744 is an F7 V star with a mass of 1.4 Msolar, an effective temperature of 6166 K, an age of 2.0 Gyr, and metallicity [Fe/H]=0.18. The radial velocity of the star has been monitored with the Advanced Fiber-Optic Echelle spectrograph at the Whipple Observatory since 1996, and evidence has been found for a low-mass companion. The data were complemented by additional data from the Hamilton spectrograph at Lick Observatory during the companion's periastron passage in the fall of 1999. As a result, we have determined the star's orbital wobble to have a period P=256 days, an orbital amplitude K=257 m s-1, and an eccentricity e=0.7. From the stellar mass, we infer that the companion has a minimum mass m2sini=7.2 MJ in an orbit with a semimajor axis a2=0.88 AU. The eccentricity of the orbit, among the highest known for extrasolar planets, continues the trend that extrasolar planets with semimajor axes greater than about 0.15 AU tend to have much higher eccentricities than are found in our solar system. The high metallicity of the parent star reinforces the trend that parent stars of extrasolar planets tend to have high metallicity. Title: Evidence for Multiple Companions to υ Andromedae Authors: Butler, R. Paul; Marcy, Geoffrey W.; Fischer, Debra A.; Brown, Timothy M.; Contos, Adam R.; Korzennik, Sylvain G.; Nisenson, Peter; Noyes, Robert W. Bibcode: 1999ApJ...526..916B Altcode: The bright F8 V star υ Andromedae was previously reported to have a 4.6 day Doppler velocity periodicity, consistent with having a Jupiter-mass companion orbiting at 0.059 AU. Follow-up observations by both the Lick and Advanced Fiber-Optic Echelle spectrometer (AFOE) planet survey programs confirm this periodicity and reveal additional periodicities at 241 and 1267 days. These periodicities are consistent with Keplerian orbital motion and imply two additional companions orbiting at 0.83 and 2.5 AU, with minimum (Msini) masses of 2.0 and 4.6 MJUP, respectively. Non-Keplerian explanations for the observed Doppler velocity variations, including radial and nonradial pulsations, rotational modulation of surface features, and stellar magnetic cycles, are examined. These explanations seem unlikely based on the observed photometric and chromospheric stability of the star. This putative three-planet system is found to be dynamically stable by both analytic techniques and numerical simulations. The outer two companions both reside in eccentric orbits, as do all nine known extrasolar planet candidates in distant orbits. If real, this multiple-planet system is the first around a main-sequence star, and its study should offer insights into planet formation, planet-planet interactions, and the observed eccentricities of planetary orbits.

Based on observations obtained at Lick Observatory, operated by the University of California, and at the Whipple Observatory, operated by the Smithsonian Astrophysical Observatory. Title: Stellar and Planetary Explorer (SPEX) Authors: Schou, J.; Bogart, R. S.; Bush, R. I.; Hoeksema, J. T.; Scherrer, P. H.; Brown, T. M.; Buzasi, D. L.; Horner, S. D.; Korzennik, S. G. Bibcode: 1999AAS...195.8808S Altcode: 1999BAAS...31.1506S The Stellar and Planetary Explorer (SPEX) mission will search for terrestrial inner planets around Sun-like (FGK, main sequence) stars using photometric techniques as well as provide very long time series for asteroseismology. If every Sun-like star had a planetary system similar to ours, the proposed instrumentation would detect at least 100 terrestrial planets similar to the Earth or Venus and be able to provide statistics on their diameters and orbital periods. SPEX will accomplish this by continuously observing a large number of field stars to detect planetary transits. The instrument consists of a fast Schmidt camera with a mosaic of large CCD detectors. SPEX will observe a field near the galactic plane from a geosynchronous orbit for a minimum of 3 years. The very long asteroseismic time series will allow inferences on the interiors of more than 100 Sun-like stars with a variety of masses and ages. This will allow us to substantially refine stellar model calculations and in particular improve on the age estimates of stars. This in turn is of considerable interest for the understanding of the evolution of our galaxy and the universe as a whole. SPEX will also provide new data for stellar activity and will be able to detect the reflected light from large inner planets, such as those detected using ground based Doppler velocity searches. Title: Evidence for a system of planets orbiting Upsilon Andromedae. Authors: Noyes, R. W.; Korzennik, S. G.; Nisenson, P.; Holman, M. J.; Contos, A.; Brown, T. M. Bibcode: 1999BAAS...31.1236N Altcode: No abstract at ADS Title: An Upper Limit on the Reflected Light from the Planet Orbiting the Star τ Bootis Authors: Charbonneau, David; Noyes, Robert W.; Korzennik, Sylvain G.; Nisenson, Peter; Jha, Saurabh; Vogt, Steven S.; Kibrick, Robert I. Bibcode: 1999ApJ...522L.145C Altcode: 1999astro.ph..7195C The planet orbiting τ Boo at a separation of 0.046 AU could produce a reflected light flux as bright as 1×10-4 relative to that of the star. A spectrum of the system will contain a reflected light component which varies in amplitude and Doppler shift as the planet orbits the star. Assuming the secondary spectrum is primarily the reflected stellar spectrum, we can limit the relative reflected light flux to be less than 5×10-5. This implies an upper limit of 0.3 for the planetary geometric albedo near 480 nm, assuming a planetary radius of 1.2 RJup. This albedo is significantly less than that of any of the giant planets of the solar system and is not consistent with certain published theoretical predictions. Title: Evidence for a System of Planets Orbiting Upsilon Andromedae Authors: Noyes, R. W.; Korzennik, S. G.; Nisenson, P.; Holman, M. J.; Contos, A.; Brown, T. M. Bibcode: 1999AAS...194.1404N Altcode: 1999BAAS...31..847N Using the Advanced Fiber Optic Echelle (AFOE) spectrograph at SAO's Whipple Observatory, we have monitored the radial velocity of Upsilon Andromedae since September 1994. Similar observations were made by the "Lick" group (P. Butler, G. Marcy, D. Fischer; see Paper 14.02).The AFOE data show, in addition to the already known close-in ``hot Jupiter'' in a 4.6-day circular orbit, two additional companions. The middle companion has a well-defined orbit, with semi-major axis about 0.83 AU, period 243.5 days, eccentricity 0.22, and minimum mass (M sin i) of 2 Jupiter masses. This is in very close agreement with independent findings by the Lick group. The AFOE data alone do not yield well-determined orbital parameters for the outer companion, because the total observing span encompasses only about one period of its orbit. However, the data are consistent with parameters derived for that companion by the Lick group from data with a longer time span, and when combined with the Lick data yield a semi-major axis of 2.5 AU, orbital period of 1267 days, eccentricity of 0.41, and minimum mass about 4.6 Jupiter masses. These results, independently obtained by two different groups with different instruments and analysis methodologies, together give strong indications that a true planetary ``system'' has now been discovered around a star like our own. We have carried out numerical integrations which show that this system can be stable, but only for certain combinations of periods, masses, and eccentricities of the outer two companions. The stability requirement thus provides a prediction that can be tested as the orbital elements of the outer companion are refined. In addition, it imposes an upper limit on the actual planetary masses, and on the difference in orbital inclination of the two outer planets. Finally, the numerical integrations imply that the longitudes of periastron of the two outer companions are locked to nearly the same value, in accord with the present observations. This work was supported by NASA, NSF, and the Smithsonian Institution. Title: Doppler Imaging of Stellar Oscillations: Multi-Site Observations of Epsilon Cephei Authors: Kennelly, E. J.; Brown, T. M.; Ehrenfreund, P.; Foing, B.; Hao, J.; Horner, S.; Korzennik, S.; Nisenson, P.; Noyes, R.; Sonnentrucker, P. Bibcode: 1999ASPC..185..264K Altcode: 1999IAUCo.170..264K; 1999psrv.conf..264K We investigate the oscillation properties of ɛ Cep using a series of specialized techniques designed to extract and analyze time variations in absorption line profiles. To obtain the necessary temporal coverage for this investigation, multi-site observations were collected at 3 sites (China, France, Arizona) all equipped with high-resolution echelle spectrographs. From these observations, we find evidence for a very rich spectrum of modes in ɛ Cep. Title: Solar Rotation Near the Surface: The Outer 1% Authors: Korzennik, Sylvain G.; Eff-Darwich, Antonio Bibcode: 1999soho....9E..68K Altcode: We present an estimate of the solar rotation rate near the surface (i.e., the outer 1%) based on rotational splittings estimated for high degree modes ( ) from the SOI/MDI dynamics program. We also present and discuss the nature and magnitude of systematic errors present in the evaluation of high degrees rotational splittings and their implication of the inferred rotation profile. Title: The Advanced Fiber-Optic Echelle (AFOE) and Extra-Solar Planet Searches Authors: Nisenson, P.; Contos, A.; Korzennik, S.; Noyes, R.; Brown, T. Bibcode: 1999ASPC..185..143N Altcode: 1999IAUCo.170..143N; 1999psrv.conf..143N The Advanced Fiber-Optic Echelle (AFOE) is a fiber-fed bench-top spectrograph specifically designed for precise radial velocity observations. The AFOE is permanently located at the 1.5-m telescope at Smithsonian's Whipple Observatory in Arizona and is regularly used for monitoring exo-planet candidate stars and for asteroseismology observations. In this paper, we discuss the status of the instrument, as well as an upgrade to the instrument, a Fabry-Perot reference, which may prove important both for the AFOE and for all precise radial velocity (PRV) facilities. Title: Response of the Stratification in the Sun to the Solar Activity Cycle Authors: Eff-Darwich, A.; Korzennik, S. G. Bibcode: 1999soho....9E..53E Altcode: We have analyzed the differences in the oscillation eigenfrequencies measured in the last three years of GONG (From September 1996 to August 1998) observations and 2 years of SOI/MDI (from May 1996 to May 1998) observations. We have inverted these data to look for signatures of the solar activity cycle on the stratification. A one-dimensional (radial) structure inversion code was used to study temporal variations of the "bump" in the sound speed distribution located in the boundary between the radiative and convective zones. These variations could be an indication of a toroidal magnetic field anchored in this region. A two-dimensional (radial and latitudinal) structure inversion code was used to analyze surface latitudinal variations of the sound speed distribution with time. We also attempted to push the inversion to deeper regions, but we failed to produce well localized solutions due to the noise present in the data. The most interesting results are those found for the sound speed distribution in the solar surface. There is a clear dependence of the angular distribution of sound speed with time. The relation between this dependence and some physical phenomena like the rising of the magnetic activity or thermal variations in the solar surface are explored. Title: The Planet Orbiting ρ Coronae Borealis Authors: Noyes, R. W.; Contos, A. R.; Korzennik, S. G.; Nisenson, P.; Brown, T. M.; Horner, S. D. Bibcode: 1999ASPC..185..162N Altcode: 1999IAUCo.170..162N; 1999psrv.conf..162N Continuing precise radial velocity observations of ρ Coronae Borealis have allowed the determination of updated parameters of the 40-day orbit of its Jupiter-mass companion. This confirms the near-zero eccentricity of the orbit, and provides improved predictions for the times of possible transit of the companion in front of the star. The new data provide more stringent upper limits to the mass of a possible second companion to the system. The orbital parameters are discussed in the light of several different scenarios for the origin and migration of extra-solar giant planets. Title: Structure and dynamics of the interior of the Sun and Sun-like stars. Proceedings. Authors: Korzennik, S. G.; Wilson, A. Bibcode: 1998sdis.book.....K Altcode: The following topics were dealt with: resonant mode characterisation; seismology of Sun-like stars: techniques and strategies; solar structure: models and inversions; local seismology, active regions and magnetic effects; solar dynamics: large-scale and small-scale flows; temporal variations of solar oscillation characteristics: short- and long-term changes and mode excitation and damping. Title: Helioseismic Studies of Differential Rotation in the Solar Envelope by the Solar Oscillations Investigation Using the Michelson Doppler Imager Authors: Schou, J.; Antia, H. M.; Basu, S.; Bogart, R. S.; Bush, R. I.; Chitre, S. M.; Christensen-Dalsgaard, J.; Di Mauro, M. P.; Dziembowski, W. A.; Eff-Darwich, A.; Gough, D. O.; Haber, D. A.; Hoeksema, J. T.; Howe, R.; Korzennik, S. G.; Kosovichev, A. G.; Larsen, R. M.; Pijpers, F. P.; Scherrer, P. H.; Sekii, T.; Tarbell, T. D.; Title, A. M.; Thompson, M. J.; Toomre, J. Bibcode: 1998ApJ...505..390S Altcode: The splitting of the frequencies of the global resonant acoustic modes of the Sun by large-scale flows and rotation permits study of the variation of angular velocity Ω with both radius and latitude within the turbulent convection zone and the deeper radiative interior. The nearly uninterrupted Doppler imaging observations, provided by the Solar Oscillations Investigation (SOI) using the Michelson Doppler Imager (MDI) on the Solar and Heliospheric Observatory (SOHO) spacecraft positioned at the L1 Lagrangian point in continuous sunlight, yield oscillation power spectra with very high signal-to-noise ratios that allow frequency splittings to be determined with exceptional accuracy. This paper reports on joint helioseismic analyses of solar rotation in the convection zone and in the outer part of the radiative core. Inversions have been obtained for a medium-l mode set (involving modes of angular degree l extending to about 250) obtained from the first 144 day interval of SOI-MDI observations in 1996. Drawing inferences about the solar internal rotation from the splitting data is a subtle process. By applying more than one inversion technique to the data, we get some indication of what are the more robust and less robust features of our inversion solutions. Here we have used seven different inversion methods. To test the reliability and sensitivity of these methods, we have performed a set of controlled experiments utilizing artificial data. This gives us some confidence in the inferences we can draw from the real solar data. The inversions of SOI-MDI data have confirmed that the decrease of Ω with latitude seen at the surface extends with little radial variation through much of the convection zone, at the base of which is an adjustment layer, called the tachocline, leading to nearly uniform rotation deeper in the radiative interior. A prominent rotational shearing layer in which Ω increases just below the surface is discernible at low to mid latitudes. Using the new data, we have also been able to study the solar rotation closer to the poles than has been achieved in previous investigations. The data have revealed that the angular velocity is distinctly lower at high latitudes than the values previously extrapolated from measurements at lower latitudes based on surface Doppler observations and helioseismology. Furthermore, we have found some evidence near latitudes of 75° of a submerged polar jet which is rotating more rapidly than its immediate surroundings. Superposed on the relatively smooth latitudinal variation in Ω are alternating zonal bands of slightly faster and slower rotation, each extending some 10° to 15° in latitude. These relatively weak banded flows have been followed by inversion to a depth of about 5% of the solar radius and appear to coincide with the evolving pattern of ``torsional oscillations'' reported from earlier surface Doppler studies. Title: Exoplanets or Dynamic Atmospheres? The Radial Velocity and Line Shape Variations of 51 Pegasi and τ Bootis Authors: Brown, Timothy M.; Kotak, Rubina; Horner, Scott D.; J. Kennelly, Edward; Korzennik, Sylvain; Nisenson, P.; Noyes, Robert W. Bibcode: 1998ApJS..117..563B Altcode: 1998astro.ph..1166B The stars 51 Pegasi and τ Bootis show radial velocity variations that have been interpreted as resulting from companions with roughly Jovian mass and orbital periods of a few days. Gray and Gray & Hatzes reported that the radial velocity signal of 51 Peg is synchronous with variations in the shape of the line λ6253 Fe I; thus, they argue that the velocity signal arises not from a companion of planetary mass but from dynamic processes in the atmosphere of the star, possibly nonradial pulsations. Here we seek confirming evidence for line shape or strength variations in both 51 Peg and τ Boo, using R = 50,000 observations taken with the Advanced Fiber Optic Echelle. Because of our relatively low spectral resolution, we compare our observations with Gray's line bisector data by fitting observed line profiles to an expansion in terms of orthogonal (Hermite) functions. To obtain an accurate comparison, we model the emergent line profiles from rotating and pulsating stars, taking the instrumental point-spread function into account. We describe this modeling process in detail. We find no evidence for line profile or strength variations at the radial velocity period in either 51 Peg or in τ Boo. For 51 Peg, our upper limit for line shape variations with 4.23 day periodicity is small enough to exclude with 10 σ confidence the bisector curvature signal reported by Gray & Hatzes; the bisector span and relative line depth signals reported by Gray are also not seen, but in this case with marginal (2 σ) confidence. We cannot, however, exclude pulsations as the source of 51 Peg's radial velocity variation because our models imply that line shape variations associated with pulsations should be much smaller than those computed by Gray & Hatzes; these smaller signals are below the detection limits both for Gray & Hatzes's data and for our own. τ Boo's large radial velocity amplitude and v sin i make it easier to test for pulsations in this star. Again we find no evidence for periodic line shape changes, at a level that rules out pulsations as the source of the radial velocity variability. We conclude that the planet hypothesis remains the most likely explanation for the existing data. Title: The Solar Rotation Rate Ω(R, θ) Authors: Eff-Darwich, A.; Korzennik, S. G.; Roca Cortés, T.; Pérez Hernández, F.; Pallé, P. Bibcode: 1998Ap&SS.263..347E Altcode: 1999Ap&SS.263..347E In recent years, the capability to detect and analyse solar oscillation acoustic modes has greatly improved. The development of ground based networks like GONG or BiSON and the use of space platforms like SOHO has allowed us to study the structure and dynamics of the Sun with unprecedented precision. Title: The Oscillations of Tau Pegasi Authors: Kennelly, E. J.; Brown, T. M.; Kotak, R.; Sigut, T. A. A.; Horner, S. D.; Korzennik, S. G.; Nisenson, P.; Noyes, R. W.; Walker, A.; Yang, S. Bibcode: 1998ApJ...495..440K Altcode: We present extensive spectroscopic time series observations of the multiperiodic, rapidly rotating, δ Scuti star τ Pegasi. Information about the oscillations is contained within the patterns of line-profile variation of the star's blended absorption-line spectrum. We introduce the new technique of Doppler deconvolution with which to extract these patterns by modeling the intrinsic stellar spectrum and the broadening functions for each spectrum in the time series. Frequencies and modes of oscillation are identified from the variations using the technique of Fourier-Doppler imaging and a two-dimensional least-squares cleaning algorithm. We find a rich mode spectrum with degrees up to l = 20 and with frequencies below about 35 cycles day-1. Those modes with the largest amplitudes have frequencies that lie within a narrow band. We conclude that the observed spectrum can be explained if the modes of τ Peg propagate in the prograde direction with l ~= |m| and with frequencies that are about equal in the corotating frame of the star. We discuss the implications of these results for the prospect of δ Scuti seismology. Title: A Search for Line Shape and Depth Variations in 51 Pegasi and τ Bootis Authors: Brown, Timothy M.; Kotak, Rubina; Horner, Scott D.; Kennelly, Edward J.; Korzennik, Sylvain; Nisenson, P.; Noyes, Robert W. Bibcode: 1998ApJ...494L..85B Altcode: 1997astro.ph.12279B Spectroscopic observations of 51 Pegasi and τ Bootis show no periodic changes in the shapes of their line profiles; these results for 51 Peg are in significant conflict with those reported by Gray & Hatzes. Our detection limits are small enough to rule out nonradial pulsations as the cause of the variability in τ Boo, but not in 51 Peg. The absence of line shape changes is consistent with these stars' radial velocity variability arising from planetary mass companions. Title: The Stellar and Planetary Explorer (SPEX) Mission Authors: Schou, J.; Scherrer, P. H.; Brown, T. M.; Frandsen, S.; Horner, S. D.; Korzennik, S. G.; Noyes, R. W.; Tarbell, T. D.; Title, A. M.; Walker, A. B. C., II; Weiss, W. W.; Bogart, R. S.; Bush, R. I.; Christensen-Dalsgaard, J.; Hoeksema, J. T.; Jones, A.; Kjeldsen, H. Bibcode: 1998ESASP.418..401S Altcode: 1998soho....6..401S The Stellar and Planetary Explorer (SPEX) is a mission designed to search for terrestrial sized planets around sun-like stars using precise photometry. The planets will be detected by searching for the decrease in brightness associated with transits of the planets in front of their parent stars. One of the secondary scientific objective of SPEX is to do asteroseismology on a number of sun-like stars. SPEX is designed as a secondary payload on a commercial communications satellite and will have a design life time of three years. We will provide an overview of the SPEX scientific objectives and design, with particular emphasis on the prospects for doing asteroseismology. Title: On the Precision of Time/Distance Measurements Authors: Baudin, F.; Korzennik, S. G. Bibcode: 1998ESASP.418..611B Altcode: 1998soho....6..611B ``Time--distance'' analysis is a emerging new tool for local (and global) helioseismology, pioneered by Duvall et al. (1993). Like for other seismological analysis techniques, time--distance analysis allow us to infer internal physical properties of the Sun from measurements made at the surface, by solving an inverse problem. In the case of time--distance analysis, the observed quantities are travel times of acoustic waves from one point of the surface to another (or between group of points). These travel times are estimated by fitting a wavelet to the correlation function computed from time-series of velocities averaged along annuli of given radius. The precision with which these measurements can be made is a crucial parameter of the inverse problem, and controls the achievable trade-off between resolution and error magnification. In the work presented here, we investigate the precision of these measurements, and how this precision varies with some of the parameters of the analysis, (like the length of the time-series, the spatial averaging, etc ldots) as well as the nature of the data used (i.e., the spatial resolution, the location of the area studied on the visible disk, etc ldots). Title: The Rotation of the Solar Core: Compatibility of the Different Data Sets Available Authors: Eff-Darwich, A.; Korzennik, S. G. Bibcode: 1998ESASP.418..685E Altcode: 1998soho....6..685E A combination of inverse and forward analysis techniques has been applied to p-modes rotational splittings in order to infer the solar rotation rate in the deeper radiative regions (r < 0.45Rodot). In this analysis, we first infer the rotation distribution down to 0.45Rodot using a 2D inversion method. We then use that rotation rate to discuss the compatibility of different low degree splittings sets. These low degree splittings and the 2D inversion method are also used to infer the rotation rate in the deeper radiative regions (r < 0.45Rodot). An exhaustive analysis of the averaging kernels has been carried out in order to study the resolution and precision of the solution. Title: Structure and Dynamics of the Interior of the Sun and Sun-like Stars Authors: Korzennik, S. Bibcode: 1998ESASP.418.....K Altcode: 1998soho....6.....K No abstract at ADS Title: Exoplanet Research with the Advanced Fiber Optic Echelle Authors: Korzennik, S. G.; Brown, T. M.; Contos, A. R.; Horner, S.; Jha, S.; Kennelly, T.; Krockenberger, M.; Nisenson, P.; Noyes, R. W. Bibcode: 1998ASPC..154.1876K Altcode: 1998csss...10.1876K The AFOE is a fiber-fed bench-top echelle spectrometer installed at the Mt. Hopkins 1.5 m telescope for research in exoplanets, asteroseismology, and other topics requiring precise radial velocity measurements. Here we describe the instrumentation, observing programs, and data reduction techniques for exoplanet research with the AFOE. We also summarize recent results of our search for and characterization of exoplanets. Further information on the AFOE can be found on the Web at http://cfa-www.harvard.edu/afoe. Title: Observational Analysis of Asymmetries in Velocity and Intensity Power Spectra Authors: Korzennik, S. G. Bibcode: 1998ESASP.418..933K Altcode: 1998soho....6..933K In order to properly characterize the the limit spectrum of the solar oscillations, we have computed averaged power spectra of both velocity and intensity time-series, using SOI/MDI observations. More precisely, we have computed the 9th order sine multi-tapered power spectrum of the zonal (m = 0) and sectoral (m = ell) time-series of spherical harmonic coefficients, for degree up to ell = 200. We computed such spectra for the 360 day-long velocity time-series and the 61-day-long, coeval, velocity and intensity time-series. Then, using the set of eigenfrequencies and rotational splitting coefficients estimated by the Stanford group and based on the 360-day-long velocity time-series, we build averaged mode profiles. These profiles were computed by summing a 200 muHz portion of the (zonal or sectoral) power spectrum, centered on the eigenfrequency estimated for that mode respectively, for a set of individual modes that lies within a preset range in degree and frequency. By averaging only zonal (or sectoral), the resulting spatial leakage pattern is simple enough to be easily understood. This averaging was performed independently for the zonal and sectoral power spectra, and for the 360 day-long velocity time-series, as well as the 61-day-long, coeval, velocity and intensity time-series. We present and discussed detailed comparisons of these profiles, and show that while the mode profile displays some intrinsic asymmetry, the amplitude of the spatial leaks display a similar asymmetry. Indeed, for the velocity observations and the sectoral profiles, the δ ell = δ m = -1, -2, -3 leaks (lower frequencies) have more power than the δ ell = δ m = +1, +2, +3 (higher frequencies), while the opposite is true for the intensity observations. A direct consequence of such leakage asymmetry (as opposed to the profile intrinsic asymmetry) is to offset the power distribution of unresolved power ridges (where the modes are short lived, i.e., for high frequency and/or high degree modes). It explains the apparent frequency differences that are measured between velocity and intensity when these are estimated by fitting unresolved ridges. Title: Temperatures of Cepheids from Line-Depth Ratios Authors: Krockenberger, M.; Sasselov, D.; Noyes, R.; Korzennik, S.; Nisenson, P.; Brown, T.; Kennelly, T.; Horner, S. Bibcode: 1998ASPC..154..791K Altcode: 1998csss...10..791K We present observations of 11 Cepheids and 16 non-variable supergiants with the Advanced Fiber Optics Echelle (AFOE) spectrograph. We measure the effective temperatures of Cepheids and supergiants using spectral line depth ratios and Kurucz's model atmospheres. For the Cepheids we use the fact that the reddening is constant as a function of phase as an additional constraint. We find errors in the mean temperature as small as 10 K for the best sampled Cepheids. Our temperatures and surface brightnesses disagree with the results of the Barnes-Evans method. Title: 51 Pegasi and Tau Bootis: Planets or Pulsations? Authors: Horner, S. D.; Brown, T. M.; Kennelly, E. J.; Kotak, R.; Jha, S.; Korzennik, S. G.; Krockenberger, M.; Nisenson, P.; Noyes, R. W. Bibcode: 1998ASPC..135..206H Altcode: 1998hcsp.conf..206H It has recently been suggested (Gray 1997) that the radial velocity variations observed in the spectra of 51 Pegasi are the result of stellar pulsations as opposed to the reflex motion due to an orbital companion. The AFOE group has confirmed the radial velocity variations in 51 Pegasi and t Bootis. Here we discuss the results of a search for evidence of pulsations in the AFOE data for these two stars, as well as attempt to clear up misconceptions regarding pulsations circulated as a result of the current debate about the nature of the 51 Pegasi radial velocity variations. Title: 51 Pegasi and Tau Bootis: Planets or Pulsations? Authors: Horner, S. D.; Brown, T. M.; Kennedy, E. J.; Kotak, R.; Jha, S.; Korzennik, S. G.; Krockenberger, M.; Nisenson, P.; Noyes, R. W. Bibcode: 1998ASPC..154.1860H Altcode: 1998csss...10.1860H Using data from the AFOE and simulations of pulsating stars, we are able to rule out pulsations as the cause of the radial velocity variations seen in tau Bootis and conclude that it is unlikely that pulsations are the cause of radial velocity variations seen in 51 Pegasi. Orbital companions are still the most probable causes of the radial velocity variations observed in these systems. Title: The SOI-MDI High-Latitude Jet: the Evidence For and Against Authors: Howe, R.; Antia, H.; Basu, S.; Christensen-Dalsgaard, J.; Korzennik, S. G.; Schou, J.; Thompson, M. J. Bibcode: 1998ESASP.418..803H Altcode: 1998soho....6..803H The apparent detection of a prograde jet at latitude 75-circ and at a radius of about 0.95Rodot in some inversions of rotation data from SOI--MDI (Schou et al., 1998) has excited considerable interest, but whether the jet really exists in the solar interior is certainly not yet firmly established. The detection of the feature is sensitive both to the inversion techniques used and to the methods of mode parameter estimation used to generate the input data. In particular, the feature is much more apparent in Regularized Least-Squares inversions than in inversions using an Optimally Localized Average approach, and is not detected at all in the present GONG data when analysed with the GONG peakfinding algorithm, or indeed in SOI data when analysed with the GONG algorithm. Therefore in this poster we examine critically the current evidence for the source and existence of this jet in the light of forward and inverse analyses. Title: Asteroseismology of Procyon with the AFOE Authors: Horner, S. D.; Brown, T. M.; Kennelly, E. J.; Korzennik, S.; Nisenson, P.; Noyes, R. W. Bibcode: 1997AAS...191.4310H Altcode: 1997BAAS...29R1276H The Advanced Fiber Optic Echelle (AFOE) is a bench-mounted, fiber-fed echelle spectrograph designed for precision radial velocity observations. Located at the 1.5m Tillinghast telescope at Whipple Observatory, the AFOE is used to detect exoplanets and is involved in several projects in asteroseismology, including asteroseismology of Sun-like stars. Procyon has been a prime target for asteroseismology of Sun-like stars due to its proximity and its spectral type (F5 IV-V). Theory predicts that due to its low surface gravity and inefficient surface convection, the amplitudes of its p-mode pulsation modes should be relatively large, though still less than 1 m\ s(-1) . While the velocity of individual modes is extremely small, observations of Procyon with the AFOE show excess power in the frequency range between 0.5 to 1.5 MHz. This power may be the result of p-mode oscillations on Procyon, and is consistent with previous results (Brown et al. 1991). However, mode identification is required to interpret the ramifications of the observations for the star's structure, which is the goal of asteroseismology. These single-site data are limited in frequency resolution, which may prevent clear identification of individual modes. Title: Rotation and Zonal Flows in the Solar Envelope from the SOHO/MDI Observations Authors: Scherrer, P. H.; Schou, J.; Bogart, R. S.; Bush, R. I.; Hoeksema, J. T.; Kosovichev, A. G.; Antia, H. M.; Chitre, S. M.; Christensen-Dalsgaard, J.; Larsen, R. M.; Pijpers, F. P.; Eff-Darwich, A.; Korzennik, S. G.; Gough, D. O.; Sekii, T.; Howe, R.; Tarbell, T.; Title, A. M.; Thompson, M. J.; Toomre, J. Bibcode: 1997AAS...191.7310S Altcode: 1997BAAS...29.1322S We report on the latest inferences concerning solar differential rotation that have been drawn from the helioseismic data that are now available from the Solar Oscillations Investigation (SOI) using the Michelson Doppler Imager (MDI) on the Solar and Heliospheric Observatory (SOHO). That spacecraft is positioned in a halo orbit near the Sun-Earth Lagrangian point L_1, in order to obtain continuous Doppler-imaged observations of the sun with high spatial fidelity. Doppler velocity, intensity and magnetic field images are recorded, based on modulations of the 676.8 nm Ni I solar absorption line. The high spatial resolution of MDI thereby permits the study of many millions of global resonant modes of solar oscillation. Determination and subsequent inversion of the frequencies of these modes, including the degeneracy-splitting by the rotation of the sun, enables us to infer how the sun's angular velocity varies throughout much of the interior. The current MDI data are providing substantial refinements to the helioseismic deductions that can be made about differential rotation both within the convection zone and in its transition to the radiative interior. The shearing layer evident in the angular velocity Omega just below the solar surface is becoming better defined, as is the adjustment layer or tachocline near the base of the convection zone. The MDI data are also revealing a prominent decrease in Omega at high latitudes from the rotation rate expressed by a simple three-term expansion in latitude that was originally deduced from surface Doppler measurements. Further, there are indications that a submerged polar vortex involving somewhat faster Omega than its surroundings exists at about 75(deg) in latitudes. Title: Erratum: A Planet Orbiting the Star Rho Coronae Borealis: Authors: Noyes, Robert W.; Jha, Saurabh; Korzennik, Sylvain G.; Krockenberger, Martin; Nisenson, Peter; Brown, Timothy M.; Kennelly, Edward J.; Horner, Scott D. Bibcode: 1997ApJ...487L.195N Altcode: In the Letter, ``A Planet Orbiting the Star ρ Coronae Borealis'' by Robert W. Noyes, Saurabh Jha, Sylvain G. Korzennik, Martin Krockenberger, Peter Nisenson, Timothy M. Brown, Edward J. Kennelly, and Scott D. Horner (ApJ, 483, L111 [1997]), a software error caused the sign of the reported radial velocity variations of ρ Coronae Borealis to be reversed. This error has no effect on the period, amplitude, or eccentricity of the derived orbit and thus does not affect the main conclusion of the paper. However, the longitude ω of periastron reported in Table 1 is off by 180°, and the predicted time of a possible planetary transit Ttransit is off by approximately 1/2 period. The correct values are ω = 30° +/- 74° and Ttransit = 2,450,657.88 +/- 0.54 HJD. Title: A Planet Orbiting the Star ρ Coronae Borealis Authors: Noyes, Robert W.; Jha, Saurabh; Korzennik, Sylvain G.; Krockenberger, Martin; Nisenson, Peter; Brown, Timothy M.; Kennelly, Edward J.; Horner, Scott D. Bibcode: 1997ApJ...483L.111N Altcode: 1997astro.ph..4248N We report the discovery of near-sinusoidal radial velocity variations of the G0V star ρ CrB, with period 39.6 days and amplitude 67 m s-1. These variations are consistent with the existence of an orbital companion in a circular orbit. Adopting a mass of 1.0 Msolar for the primary, the companion has minimum mass about 1.1 Jupiter masses and orbital radius about 0.23 AU. Such an orbital radius is too large for tidal circularization of an initially eccentric orbit during the lifetime of the star, and hence we suggest that the low eccentricity is primordial, as would be expected for a planet formed in a dissipative circumstellar disk. Title: A Radial Velocity Search for p-Mode Pulsations in η Bootis Authors: Brown, Timothy M.; Kennelly, Edward J.; Korzennik, Sylvain G.; Nisenson, Peter; Noyes, Robert W.; Horner, Scott D. Bibcode: 1997ApJ...475..322B Altcode: The subgiant η Boo (G5 IV) has been reported to show p-mode pulsations, as evidenced by variations in the equivalent width of its hydrogen Balmer lines (reported by Kjeldsen et al.). In an attempt to confirm this report, we observed η Boo's radial velocity with the AFOE spectrograph for a total of 22 hours spread over seven successive nights in 1995 March. We find no evidence for the presence of excess power at the frequencies reported by Kjeldsen et al.; our upper limit corresponds to typical mode amplitudes of 0.5 m s-1, about 3 times smaller than the velocity amplitudes they inferred. Signals with amplitudes larger than 0.5 m s-1 may be present at other frequencies within the 0-1000 μHz range, but evidence for such signals is scanty, and typical mode amplitudes greater than 1.5 m s-1 are clearly inconsistent with our observations. Title: Internal rotation and dynamics of the Sun from GONG data Authors: Korzennik, S.; Thompson, M. J.; Toomre, J.; GONG Internal Rotation Team Bibcode: 1997IAUS..181..211K Altcode: No abstract at ADS Title: The AFOE Program of Extra-Solar Planet Research Authors: Noyes, R.; Jha, S.; Korzennik, S.; Krockenberger, M.; Nisenson, P.; Brown, T.; Kennelly, E.; Horner, S. Bibcode: 1997ASPC..119..119N Altcode: 1997pbss.conf..119N No abstract at ADS Title: The first results of solar observations made in the Crimean Astrophysical Observatory using a magneto-optical filter Authors: Didkovskii, L. V.; Dolgushin, A. I.; Kotov, V. A.; Khaneychuk, V. I.; Tsap, T. T.; Rhodes, E. J.; Korzennik, S. G.; Johnson, N. M.; Rose, P. J. Bibcode: 1996R&QE...39..916D Altcode: The results of observations of Doppler velocities and solar magnetic fields using a magneto- optical filter (MOF) are presented. The MOF-based instrument was manufactured and supplied to the Crimean Astrophysical Observatory (CrAO) by the University of Southern California. It is one of three similar instruments designed to establish the helioseismology network „Mount Wilson —CrAO — AFiF” (Fesenkov Astrophysical Institute in Alma- Ata.) Apart from its main purpose — obtaining a long time series of the Doppler velocity measurements to study the internal solar structure and recording the magnetic fields for the ground- based support of the SOHO project — the instrument allows us to study different structural formations in the solar atmosphere in Na D1 and D2 spectral lines. This conclusion relies on the comparison between the magnetic field and beam velocity maps calculated using the filtergram pairs, which were recorded twice a minute by 512×512 video-camera (1024×1024 camera will be used in the future studies). Title: A radial velocity search for p-modes in Procyon. Authors: Brown, T. M.; Kennelly, E. J.; Noyes, R. W.; Korzennik, S. G.; Nisenson, P.; Horner, S. D.; Catala, C. Bibcode: 1996BAAS...28..917B Altcode: No abstract at ADS Title: The oscillation modes of ɛ Cep and τ Peg. Authors: Horner, S. D.; Kennelly, E. J.; Brown, T. M.; Noyes, R. W.; Korzennik, S. G.; Nisenson, P.; Yang, S.; Walker, A. R. Bibcode: 1996BAAS...28..916H Altcode: No abstract at ADS Title: Differential Rotation and Dynamics of the Solar Interior Authors: Thompson, M. J.; Toomre, J.; Anderson, E. R.; Antia, H. M.; Berthomieu, G.; Burtonclay, D.; Chitre, S. M.; Christensen-Dalsgaard, J.; Corbard, T.; De Rosa, M.; Genovese, C. R.; Gough, D. O.; Haber, D. A.; Harvey, J. W.; Hill, F.; Howe, R.; Korzennik, S. G.; Kosovichev, A. G.; Leibacher, J. W.; Pijpers, F. P.; Provost, J.; Rhodes, E. J., Jr.; Schou, J.; Sekii, T.; Stark, P. B.; Wilson, P. R. Bibcode: 1996Sci...272.1300T Altcode: Splitting of the sun's global oscillation frequencies by large-scale flows can be used to investigate how rotation varies with radius and latitude within the solar interior. The nearly uninterrupted observations by the Global Oscillation Network Group (GONG) yield oscillation power spectra with high duty cycles and high signal-to-noise ratios. Frequency splittings derived from GONG observations confirm that the variation of rotation rate with latitude seen at the surface carries through much of the convection zone, at the base of which is an adjustment layer leading to latitudinally independent rotation at greater depths. A distinctive shear layer just below the surface is discernible at low to mid-latitudes. Title: The Oscillation Modes of epsilon CEP and tau Peg Authors: Horner, S. D.; Kennelly, E. J.; Brown, T. M.; Noyes, R. W.; Korzennik, S. G.; Nisenson, P.; Yang, S.; Walker, A. Bibcode: 1996AAS...188.5901H Altcode: 1996BAAS...28Q.917H Asteroseismology of delta Scuti stars offers an attractive prospect for determining the interior properties of main sequence and slightly more evolved A- and F-type stars. Here we present detailed identifications of oscillation modes in the rapidly rotating delta Scuti stars epsilon Cep and tau Peg based on extensive observations carried out at two North American sites. Using cross-correlation and Fourier techniques we analyze the line-profile variations and the variations in the line-profile moments. A solution to the mode spectrum is sought using a genetic-based search algorithm and a line profile simulation model to reproduce the observed variations. Title: Use of Temperature-Sensitive Line Ratios for Stellar Seismology Authors: Noyes, R. W.; Korzennik, S. G.; Krockenberger, M.; Nisenson, P.; Brown, T.; Kennelly, T.; Horner, S. Bibcode: 1996AAS...188.5906N Altcode: 1996BAAS...28..918N The line depths of virtually all stellar spectral lines are sensitive to small changes in stellar temperature Teff induced by pulsations, with varying degrees (and signs) depending on the mean Teff and the line ionization and excitation state. For large-amplitude pulsators, such as Cepheids, temperatures obtained from individual line pairs are sufficiently accurate and invariant to reddening to play an important role in distance measurements. For small-amplitude pulsators, this technique is inadequate. However, by combining the information from a very large number of spectral lines recorded with high spectral resolution, such as can be provided by a cross-dispersed echelle spectrograph, it should be possible to measure temperature changes to a precision considerably greater than can be obtained by comparing single pairs of lines. We explore this possibility by using a grid of synthetic stellar spectra to provide the run of temperature sensitivity as a function of wavelength throughout the spectrum, and make specific application to spectra obtained with the Advanced Fiber Optic Echelle (AFOE) spectrograph. Title: The Solar Acoustic Spectrum and Eigenmode Parameters Authors: Hill, F.; Stark, P. B.; Stebbins, R. T.; Anderson, E. R.; Antia, H. M.; Brown, T. M.; Duvall, T. L., Jr.; Haber, D. A.; Harvey, J. W.; Hathaway, D. H.; Howe, R.; Hubbard, R. P.; Jones, H. P.; Kennedy, J. R.; Korzennik, S. G.; Kosovichev, A. G.; Leibacher, J. W.; Libbrecht, K. G.; Pintar, J. A.; Rhodes, E. J., Jr.; Schou, J.; Thompson, M. J.; Tomczyk, S.; Toner, C. G.; Toussaint, R.; Williams, W. E. Bibcode: 1996Sci...272.1292H Altcode: The Global Oscillation Network Group (GONG) project estimates the frequencies, amplitudes, and linewidths of more than 250,000 acoustic resonances of the sun from data sets lasting 36 days. The frequency resolution of a single data set is 0.321 microhertz. For frequencies averaged over the azimuthal order m, the median formal error is 0.044 microhertz, and the associated median fractional error is 1.6 x 10-5. For a 3-year data set, the fractional error is expected to be 3 x 10-6. The GONG m-averaged frequency measurements differ from other helioseismic data sets by 0.03 to 0.08 microhertz. The differences arise from a combination of systematic errors, random errors, and possible changes in solar structure. Title: A Radial Velocity Search for p-modes in Procyon Authors: Brown, T. M.; Kennelly, E. J.; Noyes, R. W.; Korzennik, S. G.; Nisenson, P.; Horner, S. D.; Catala, C. Bibcode: 1996AAS...188.5902B Altcode: 1996BAAS...28R.917B Procyon (alpha CMi F5 IV) has long been a promising candidate for detection of solar-like p-modes. Although several authors have reported evidence for low-amplitude (<= 10) m/s pulsations in this star, none of the existing observations are conclusive. A clear detection of such pulsations would be a significant step for asteroseismology of Sun-like stars, allowing refined estimates of the star's properties and paving the way for the study of fainter stars of similar spectral type. Identification of oscillation modes in subgiants like Procyon is expected to be difficult, however, because both the amplitudes and the frequency separations of the modes are expected to be small. To address these difficulties, we organized a joint observing campaign involving the AFOE spectrograph located at the Whipple Observatory (Mt. Hopkins, AZ) and the MUSICOS spectrograph located at Pic du Midi. Both instruments are capable of providing Doppler measurements with the required precision of a few m/s, and the 7 hour longitude separation between them allows the acquisition of relatively long uninterrupted data strings. In the event, bad weather prevented more than sporadic observations from Pic du Midi. At Mt. Hopkins, however, we obtained good observations on each of 6 consecutive nights 3-8 Feb 1996, for a total of 47 h of observing time. We discuss here the interpretation of this data set in terms of possible p-mode oscillations. Title: HD 3346 Authors: Noyes, R.; Korzennik, S.; Nisenson, P.; Jha, S.; Krockenberger, M.; Brown, T.; Kennelly, T.; Rowland, C.; Horner, S. Bibcode: 1996IAUC.6316....1N Altcode: 1996IAUC.6316Q...1N R. Noyes, S. Korzennik, P. Nisenson, S. Jha, and M. Krockenberger, Smithsonian Astrophysical Observatory; T. Brown, T. Kennelly, and C. Rowland, High Altitude Observatory; and S. Horner, Pennsylvania State University, report the detection of large short- term radial-velocity variations in the K5 III star HD 3346 = HR 152. Irregularly spaced observations were made with the Advanced Fiber Optic Echelle (AFOE) spectrometer at the 1.5-m telescope of the Whipple Observatory during the last quarters of 1993, 1994, and 1995, with more intensive observations in December 1995 and February 1996. A long-period radial-velocity variation similar to that already reported by McClure et al. (1985, PASP 97, 740) is seen with amplitude of order 500 m/s and period of order 650 days. This is consistent with a companion to HD 3346 at orbital distance about 2.5 AU. If the mass of HD 3346 is 5 solar masses, then this already-reported companion would have projected mass m sin i about 60 Jupiter masses. The AFOE data reveal the presence of shorter- term radial-velocity variations superimposed on the 650-day variation. The amplitude of the variations is in the range 150-300 m/s. Near-nightly observations in December 1995 and February 1996 show the variations to be consistent with those produced by a second orbital companion. The window function of the data would allow for its period to be near 14, 18, 24, or 40 days. Such a short period would imply that the second companion's orbit would have a semimajor axis between 0.2 and 0.4 AU; the amplitude of the variation implies that (again, if HD 3346 has a mass of 5 solar masses) this second companion has m sin i about 10 Jupiter masses. Acoustic pulsations may be an alternative source of the short-term radial-velocity variations. However, the fundamental period of acoustic pulsations in giants is expected to be only a few days; the present data could be explained by acoustic pulsations only if the star has a mass much lower than suggested by standard stellar- evolution theory. Spurious signals due to rotation of starspots appear to be unlikely because of the low reported rotational velocity for HD 3346. A definitive period for the short-period radial-velocity variation may be determinable if other contemporaneous precise radial-velocity observations of this star exist or can be obtained before the star disappears behind the sun for this observing season. Title: First Results of Solar Oscillations Made in Crimean Astrophysical Observatory Using Magneto-Optical Filter Authors: Didkovsky, L. V.; Rhodes, E. J., Jr.; Dolgushin, A. I.; Haneychuk, V. I.; Johnson, N. M.; Korzennik, S. G.; Kotov, V. A.; Rose, P. J.; Tasp, T. T. Bibcode: 1996RaF....39...11D Altcode: No abstract at ADS Title: A Radial Velocity Search for p-mode Pulsations in eta Bootis Authors: Noyes, R. W.; Korzennik, S. G.; Nisenson, P.; Brown, T. M.; Kennelly, E. J.; Horner, S. D. Bibcode: 1995AAS...18710211N Altcode: 1995BAAS...27.1429N Kjeldsen et al. 1994 (Astron. J 109, 1313 ) have reported the presence of p-mode pulsations in Balmer line equivalent widths measured in the spectrum of eta Boo (G5 IV); they give accurate frequencies for 13 modes of oscillation, and estimate velocity amplitudes for these modes of typically 1.6 m/s. We report here time-series observations of the radial velocity of eta Boo obtained with the Advanced Fiber Optic Echelle (AFOE) spectrograph. In March 1995 we obtained 555 spectra of eta Boo for a total of 21.6 hours of observing time spread over 7 consecutive nights. The radial velocity time series clearly shows the night-to-night orbital motion of eta Boo; the residual velocities after removing this motion are typically 10 m/s for single spectra, a value that is roughly consistent with shot noise limits. The power spectrum of the time series shows no evidence for Kjeldsen et al.'s frequencies. With 95 % confidence, we can rule out the presence of these 13 frequencies with typical amplitudes of 0.5 m/s or more. The spectrum is consistent with pure photon noise, but also with the presence of pulsations having other frequencies (not those given by Kjeldsen et al.) and with typical amplitudes as large as about 1.5 m/s. Possible explanations for the discrepancy between the two results are (a) an incorrect conversion between the amplitudes of equivalent width and Doppler pulsations, and (b) a fluke in the noise behavior of one or both observations. Title: Velocity Fields within the Solar Convection Zone: Evidence from Oscillation Ring Diagram Analysis of Mount Wilson Dopplergrams Authors: Patron, J.; Hill, F.; Rhodes, E. J., Jr.; Korzennik, S. G.; Cacciani, A. Bibcode: 1995ApJ...455..746P Altcode: A ring-diagram analysis of solar oscillations has been applied to a 3 day time series of full-disk Doppler images obtained at Mount Wilson. A model of the three-dimensional power spectrum assuming a Lorentzian profile in frequency and the advection of the wave front by horizontal flows has been fitted to the observed spectrum. The model provides estimates of the two horizontal components of subsurface flows averaged over depth. These estimates are then input to a least-squares smoothness-constrained inversion procedure to infer the depth dependence of the horizontal velocity. The method has been applied at nine different heliographic positions. The results indicate the presence of three east-west shear layers at all longitudes and latitudes, associated in depth with the ionization zones of hydrogen and helium in the outermost 20 Mm. The direction of the shear with respect to the average surface rotation rate alternates with depth, with organized north-south flows apparent between the east-west flows. Thus, the resultant vector velocity field appears to execute a spiral as a function of depth. Below ∼30 Mm, the organized character of the flow disappears, and a chaotic spatial distribution dominates. There is also an indication of a convergent flow at ∼10° north latitude, suggesting the presence of a toroidal convective roll. The magnitudes of the flows are on the order of 100-200 ms-1 in the outer 20 Mm, rising to several hundred ms-1 at 50 Mm. Title: Determining the AFOE's Radial Velocity Precision with Solar Observations Authors: Horner, S. D.; Brown, T. M.; Kennelly, E. J.; Noyes, R. W.; Korzennik, S. G.; Nisenson, P.; Krockenberger, M. Bibcode: 1995AAS...187.7006H Altcode: 1995BAAS...27.1380H The Advanced Fiber Optic Echelle (AFOE) is an instrument designed for high precision radial velocity observations to detect extra-solar planets and study stellar structure through asteroseismology. A 320 mu m optical fiber is used to obtain solar observations during the day to determine the precision of the instrument, and to study the relationship between stellar activity and measured radial velocities. Here we present the results of our analysis of solar data to determine the short and long term radial velocity precision of the AFOE. Title: 51 Pegasi Authors: Mayor, M.; Queloz, D.; Marcy, G.; Butler, P.; Noyes, R.; Korzennik, S.; Krockenberger, M.; Nisenson, P.; Brown, T.; Kennelly, T.; Rowland, C.; Horner, S.; Burki, G.; Burnet, M.; Kunzli, M. Bibcode: 1995IAUC.6251....1M Altcode: M. Mayor and D. Queloz, Geneva Observatory, have reported the discovery of a Jupiter-mass object in orbit around the solar-type star 51 Peg. The announcement was made in Florence on Oct. 6 at the Ninth "Cambridge" Workshop on "Cool Stars, Stellar Systems, and the Sun". The claim is based on 18 months of precise Doppler measurements made with the ELODIE spectrograph of the Observatoire de Haute-Provence. The parameters of the orbital motion are as follows: P = 4.2293 +/- 0.0011 days, e = 0 (assumed), K = 0.059 +/- 0.003 km/s, T0 = 2449797.773 +/- 0.036. The minimum mass of the companion is 0.47 +/- 0.02 Jupiter mass. Alternative explanations for the radial-velocity variation (pulsation or spot rotation) seem to be ruled out by the absence of any significant corresponding photometric variation. Following the Oct. 6 announcement, confirmation of the 4.2-day radial-velocity variation was obtained in mid-October by G. Marcy and P. Butler (San Francisco State University, University of California at Berkeley) at the Lick Observatory, as well as by a joint team from the Harvard-Smithsonian Center for Astrophysics (R. Noyes, S. Korzennik, M. Krockenberger and P. Nisenson), the High Altitude Observatory (T. Brown, T. Kennelly and C. Rowland) and Pennsylvania State University (S. Horner). G. Burki, M. Burnet and M. Kuenzli, Geneva Observatory and Lausanne University, communicate: "Intensive photometric monitoring of 51 Peg has been carried out at the European Southern Observatory. There is no evidence for eclipses in the system. The rms of the V magnitude (on 17 nights) is 0.037, two comparison stars being used. A 4.2-day photometric variability larger than 0.002 mag can be ruled out." Title: Adjustment and Focus of Solar Images for Magneto-Optical Filter Observations Authors: Didkovsky, L. V.; Andreeva, O. A.; Borzyak, P. I.; Dolgushin, A. I.; Rhodes, E. J.; Johnson, N. M.; Rose, P. J.; Korzennik, S. G. Bibcode: 1995ESASP.376b.201D Altcode: 1995help.confP.201D; 1995soho....2..201D Provides a more accurate and reliable set of full-disk, high-resolution helioseismic measurements in the M. Wilson-Crimea-Alma-Ata network by ensuring the optimum quality of the solar images which will be generated by each network station. The method of optical layout adjustment is based on real-time, PC-based programs for improving the quality of solar images. The best focus is determined through motion of the camera followed by the checking of the mean inclination angle of the brightness curves in several equi-spaced azimuthal directions. The solar limb shape is adjusted to obtain the minimum standard deviation around the circle through the alignment of the lenses and the video camera. Finally, the camera and the re-imaging lens are positioned so as to have a common image size as well as the optimum focus. As a part of the daily observing procedure, the solar image is focused by another algorithm which is sensitive to the maximum intensity of some bright objects on the solar image. Title: Method Optimization for Calculating the Solar-Limb Position Authors: Didkovsky, L. V.; Andreeva, O. A.; Borzyak, P. I.; Dolgushin, A. I.; Rhodes, E. J.; Johnson, N. M.; Rose, P. J.; Korzennik, S. G. Bibcode: 1995ESASP.376b.197D Altcode: 1995soho....2..197D; 1995help.confP.197D The solar limb figure is determined using the middle of linear segments drawn by a least squares method through brightness profiles and maximum slopes. The brightness profiles employed are equally spaced in the azimuthal angle. The authors show that there is an optimal width for the ring-shaped zone (r/R ≡ 5%) which is used for the limb determination. In this case the run of standard deviations of the limb points from a circle has a clear minimum which is 1.3 times smaller than the standard deviation found with the "activity-based" algorithm. During iteration cycles the error in determinating the centre of the solar image gets smaller and reaches a limiting value which is conditioned by the shape of the image. The proposed method of solar limb determination is intended to decrease possible errors in the identification of the degrees of the high-l oscillation modes and to achieve higher computational efficiency. Title: Looking for Non-Local Features in Horizontal Velocity Flows Authors: Patrón, J.; Rhodes, E. J., Jr.; Korzennik, S. G. Bibcode: 1995ESASP.376b.133P Altcode: 1995help.confP.133P; 1995soho....2..133P The tridimensional maps of horizontal velocity flows obtained with ring diagrams analysis techniques show several common features at given depths for different horizontal positions. This could be interpreted as global, rather than local features. Tests have been performed in order to find large scale horizontal velocity flows under the solar surface. The procedure, based in a tridimensional analysis of solar oscillations (ring diagrams), has been applied to a section of the solar disk of about 45 degrees in latitude and longitude around solar disk center. The images used in this work correspond to three days of 1024×1024 pixel Doppler images obtained at Mt. Wilson July 3, 4, and 5, 1988 using the Magneto-Optical Filter. By using large scale sections of the solar disk, it is possible to expect an averaging or filtering effect of the local features of the results (horizontal velocity flows), giving rise to information about more global features. Title: Restoration of Full-Disk Velocity Maps Obtained with Magneto-Optical Filter Authors: Didkovsky, L. V.; Andreeva, O. A.; Borzyak, P. I.; Dolgushin, A. I.; Rhodes, E. J.; Johnson, N. M.; Rose, P. J.; Korzennik, S. G. Bibcode: 1995ESASP.376b.191D Altcode: 1995soho....2..191D; 1995help.confP.191D In order to improve the calibration of solar Dopplergrams in the sense of reducing the standard errors connected with large-scale nonlinearities, the authors have tested some new algorithms. The method of the determination of the boundaries between both linear and non-linear variation of the filtergram signal, as well as the method of a variable window running mean has been used. The new velocity maps which result from the application of these methods show good agreement with velocity maps obtained independently with a spectrograph. Title: Nightly Variations of Nonradial Oscillations in the Delta Scuti Star upsilon Ursae Majoris Authors: Korzennik, S. G.; Noyes, R. W.; Brown, T.; Nisenson, P.; Horner, S. Bibcode: 1995ApJ...443L..25K Altcode: We obtained spectra of the rapidly rotating Delta Scuti star upsilon UMa with the Advanced Fiber Optic Echelle Spectrometer (AFOE) on five successive nights in 1993 April, at a cadence of one spectrum every 5 minutes over time periods averaging 4 hours on each night. Cross-correlations of the spectra with a template spectrum from a slowly rotating star of similar spectral type yielded the pattern of features propagating across the lines, averaged over all spectral lines recorded. The spacing of the features in wavelength and their speed of motion across the line profile depend on the azimuthal order m and frequency v of propagating oscillation modes. Using a Doppler imaging analysis, we computed nightly absolute value of m-v diagrams; these show several resolved modes with effective azimuthal order m ranging from about 2 up to about 11, and frequencies between 130 and 170 microHz (i.e., periods between 2.1 and 1.6 hours). We identify the observed modes as propagating prograde modes; the corresponding retrograde modes are not observed. Viewed in a frame corotating with the star with rotation speed of 116 km/s as derived from these data, modes with m approximately 7 and with m approximately 11 have approximately the same frequency (70 microHz). However, their relative amplitude changes substantially from night to night, suggesting that (1) the coherence time of the modes is not longer than about 1 day, or (2) a possible coupling between modes of similar intrinsic frequencies causes an alternating pattern of modal amplitude, or (3) beats are being observed between unresolved modes of similar wavelength and frequency. Title: Compensation of Large-Area Non-Linearities in Solar Velocity Maps Obtained with a Sodium Magneto-Optical Filter Authors: Didkovsky, L. V.; Andreeva, O. A.; Borzyak, P. I.; Dolugshin, A. I.; Rhodes, E. J., Jr.; Johnson, N. M.; Rose, P.; Korzennik, S. G. Bibcode: 1995ASPC...76..536D Altcode: 1995gong.conf..536D No abstract at ADS Title: Local Helioseismology: Analysis of Localized Time-Distance Diagrams from Quiet and Active Regions Authors: Korzennik, S. G.; Noyes, R. W.; Ziskin, V. Bibcode: 1995ASPC...76..268K Altcode: 1995gong.conf..268K No abstract at ADS Title: Ring Diagram Analysis of Mt. Wilson Data: Velocity Fields within the Solar Convection Zone Authors: Patron, J.; Hill, F.; Rhodes, E. J., Jr.; Korzennik, S. G.; Cacciani, A. Bibcode: 1995ASPC...76..208P Altcode: 1995gong.conf..208P No abstract at ADS Title: Solar Cycle Dependence of p-Mode Frequencies at Intermediate and High Degrees Authors: Rhodes, E. J., Jr.; Johnson, N. M.; Rose, P. J.; Korzennik, S. G.; Cacciani, A. Bibcode: 1995ASPC...76..227R Altcode: 1995gong.conf..227R No abstract at ADS Title: Applications of Massively-Parallel Computing in Solar Modeling Authors: Reiter, J.; Rhodes, E. J., Jr.; Dappen, W.; Korzennik, S. G. Bibcode: 1995ASPC...76..140R Altcode: 1995gong.conf..140R No abstract at ADS Title: On the Determination of the Solar Internal Rotation Authors: Korzennik, S. G.; Rhodes, E. J., Jr.; Johnson, N. M.; Rose, P.; Cacciani, A. Bibcode: 1995ASPC...76...12K Altcode: 1995gong.conf...12K No abstract at ADS Title: The AFOE: A Spectrograph for Precision Doppler Studies Authors: Brown, Timothy M.; Noyes, Robert W.; Nisenson, Peter; Korzennik, Sylvain G.; Horner, Scott Bibcode: 1994PASP..106.1285B Altcode: The Advanced Fiber Optic Echelle (AFOE) is a fiber-fed echelle spectrograph designed for the measurement of stellar Doppler shifts. Using a 2k x 2k CCD detector, it samples about 55% of the wavelength range between 450 nm and 700 nm (20 echelle orders) at a single shot, with spectral resolution R = 32000 to 70000 at 500 nm, depending on the slit width employed. The AFOE employs a number of devices to assure that the calibrations necessary for accurate Doppler measurements can be properly performed. The most important of these are: (1) coupling to the telescope via a double-scrambling optical fiber system; (2) continuous calibration of the wavelength scale and point-spread function by means of an atomic emission lamp entering the spectrograph via a separate fiber and/or a molecular iodine absorption cell; (3) availability of fiber-coupled sunlight for regular calibration against the solar spectrum; (4) appropriate mechanical design and active thermal control, yielding good mechanical stability. The AFOE is coupled to the Tillinghast 1.5-m telescope at the F. L. Whipple Observatory. It presently achieves S/N = 500 in the continuum near 500 nm in 60s when observing Arcturus (alpha-Boo, m_V = -0.04). This noise level sets a limit of about 0.7 ms^-1 to the Doppler precision attainable in this length of observing time. Currently, our actual frame-to-frame repeatability is worse than the photon noise limited value by about a factor of 3 for this bright star, and about 1.5 for stars with m_V = 4. Work is continuing to refine data processing methods so that the ultimate noise limit may be approached more closely, and to improve the spectrograph's relatively low efficiency. (SECTION: Astronomical Instrumentation ) Title: Nightly Variations of Non-Radial Oscillations in the Delta Scuti Star upsilon UMa Authors: Korzennik, S.; Noyes, R.; Brown, T.; Nisenson, P.; Horner, S. Bibcode: 1993AAS...183.8405K Altcode: 1993BAAS...25.1423K We observed the rapidly rotating Delta Scuti star upsilon UMa with the Advanced Fiber Optic Echelle (AFOE) spectrometer at the Mt. Hopkins 1.5-m telescope on 5 successive nights in April 1993. Spectra covering a total of 730 Angstroms were obtained at a 5-min cadence over about 4 hours on each night. The rotationally-broadened profiles of unblended strong lines clearly show previously-seen ``bumps" propagating from the blue side to the red side of the lines. We isolated moving features for each individual spectrum by subtracting the spectrum from the mean spectrum for that night, normalizing to the latter. We then calculated the cross-correlation function between each difference spectrum and a standard template spectrum, which was a very high signal-to-noise spectrum of a slowly-rotating star (Procyon) of similar spectral type, obtained with the same instrument. The cross-correlation combines the information from all the bumps moving across all spectral lines (including rotationally-blended lines) into a single function of displacement from line center, thereby significantly increasing the signal-to-noise ratio of the moving features. Analysis of the time-series of cross-correlation functions yields the rate of propagation of features and their separation in velocity, which may be interpreted in terms of effective azimuthal wavenumber and oscillation frequency. Modes are identified by remapping the cross-correlation functions in terms of longitude and performing two-dimensional Fourier transforms. For each night a different modal pattern was found, usually with several modes. The modes have effective azimuthal order m ranging from about 2 up to about 12, and frequencies between 120 and 170 uHz (i.e., 2.3 to 1.6 hours), with frequency gradually increasing with increasing m. The relative amplitude of the different modes changes substantially from night to night, suggesting either that the coherence time of the modes is not longer than about a day, or that beats are being observed between modes of similar wavelength and frequency. Title: Ring Diagram Analysis of Mt. Wilson Data: Current Status Authors: Hill, F.; Patron, J.; Rhodes, E. J., Jr.; Korzennik, S. G.; Cacciani, A. Bibcode: 1993BAAS...25R1193H Altcode: No abstract at ADS Title: Confirmation of Solar Cycle--dependent Intermediate-Degree p-Mode Frequency Shifts Authors: Rhodes, Edward J., Jr.; Cacciani, Alessandro; Korzennik, Sylvain G.; Ulrich, Roger K. Bibcode: 1993ApJ...406..714R Altcode: Results of intercomparisons of seven different sets of frequencies of intermediate-degree p-modes obtained at several different locations between 1981 and 1989 are presented. It is shown that the frequency shifts exhibited by all of these intermediate-degree p-modes are consistent with the intermediate-degree frequency shifts presented by Libbrecht and Woodward (1990) and also with the low-degree frequency shifts presented by Elsworth et al. (1990). It is also shown that these frequency shifts correlate with solar cycle-dependent changes in sunspot number, area, and irradiance. Unbinned and binned differences between 1984 Mount Wilson Observatory and revised 1981 South Pole frequencies are illustrated. Title: Ring Diagram Analysis of MT.WILSON Data Authors: Patron, J.; Hill, F.; Rhodes, E. J., Jr.; Korzennik, S. G.; Cacciani, A.; Brown, T. M. Bibcode: 1993ASPC...42..437P Altcode: 1993gong.conf..437P No abstract at ADS Title: Preliminary P-Mode Frequencies from a 93-DAY MT.WILSON 60-FOOT Tower Observing Run Authors: Rhodes, E. J., Jr.; Cacciani, A.; Korzennik, S. G. Bibcode: 1993ASPC...42..193R Altcode: 1993gong.conf..193R No abstract at ADS Title: Helioseismology on a Massively Parallel Architecture - Reduction of 1024-by-1024 Full-Disk Dopplergrams on Intel's Touchstone-Delta Supercomputer Authors: Korzennik, S. G.; Rhodes, E. J., Jr.; Johnson, N. M. Bibcode: 1993ASPC...42..461K Altcode: 1993gong.conf..461K No abstract at ADS Title: Towards a Better Determination of Frequency Splittings at Intermediate and High Degree Modes - Preliminary Results of Sectoral Frequency Splittings from a 90-DAY Observing Run Authors: Korzennik, S. G.; Cacciani, A.; Rhodes, E. J., Jr. Bibcode: 1993ASPC...42..201K Altcode: 1993gong.conf..201K No abstract at ADS Title: An Advanced Fiber Optic Echelle Spectrograph for Asteroseismology Authors: Noyes, R. W.; Brown, T. M.; Horner, S.; Korzennik, S.; Nisenson, P. Bibcode: 1993ASPC...42..485N Altcode: 1993gong.conf..485N No abstract at ADS Title: The AFOE - a new instrument for asteroseismology Authors: Noyes, R. W.; Brown, T. M.; Horner, S.; Korzennik, S.; Nisenson, P. Bibcode: 1993ASPC...40..752N Altcode: 1993IAUCo.137..752N; 1993ist..proc..752N No abstract at ADS Title: Measurement of the Phase Relation Between Velocity and Intensity Fluctuations Authors: Korzennik, S. G.; Sabbey, C. N. Bibcode: 1993ASPC...42..115K Altcode: 1993gong.conf..115K No abstract at ADS Title: Plans for MT.WILSON - Crimean Observatory High-Degree Helioseismology Network Authors: Rhodes, E. J., Jr.; Cacciani, A.; Dappen, W.; Didkovsky, L. V.; Hill, F.; Korzennik, S. G.; Kosovichev, A. G.; Kotov, V. A.; Scherrer, P. H. Bibcode: 1993ASPC...42..477R Altcode: 1993gong.conf..477R No abstract at ADS Title: Rotation Rate of the Supergranulation Pattern Authors: Hathaway, D. H.; Rhodes, E. J., Jr.; Korzennik, S.; Cacciani, A. Bibcode: 1991BAAS...23.1051H Altcode: No abstract at ADS Title: Seismic Analysis of the Sun from Intermediate and High Degree p-modes Authors: Korzennik, S. G. Bibcode: 1991BAAS...23Q1032K Altcode: No abstract at ADS Title: How Deeply Might Sunspots and Supergranules Be Anchored within the Sun? Authors: Rhodes, E. J., Jr.; Korzennik, S. G.; Hathaway, D. H.; Cacciani, A. Bibcode: 1991BAAS...23.1033R Altcode: No abstract at ADS Title: What We Know about the Sun's Internal Rotation from Solar Oscillations Authors: Goode, Philip R.; Dziembowski, W. A.; Korzennik, S. G.; Rhodes, E. J., Jr. Bibcode: 1991ApJ...367..649G Altcode: In this paper, a uniform approach of inversion was used to determine the internal rotation rate of the sun from each of the six available sets of solar oscillation data, which included the data of Duvall et al. (1986), Rhodes et al. (1987, 1990), Tomczyk (1988), Brown and Morrow (1987), and Libbrecht (1989). The technique chosen for inverting the solar oscillation data was the discretized least-squares technique. The results indicate that the rotation rate of the sun in the equatorial plane declines going inward between the surface and 0.6 of the radius and that the polar rate increases going inward (i.e., the surfacelike differential rotation decreases with depth). Title: The Supergranulation Spectrum Authors: Hathaway, David H.; Rhodes, Edward J.; Cacciani, Alessandro; Korzennik, Sylvain G. Bibcode: 1991LNP...388..163H Altcode: 1991ctsm.conf..163H Full-disk Dopplergram observations obtained at the 60-foot tower of the Mount Wilson Observatory with the Cacciani sodium magneto-optical filter were analyzed to determine the spectrum of the solar supergranulation. Individual Dopplergrams were averaged together using a weighted average over 20-minute intervals to remove the p-mode oscillations. The Doppler signals due to the motion of the observer, the solar rotation, differential rotation, and limb shift were then removed from the data to produce Dopplergrams dominated by the supergranular flows. These data were mapped to heliographic coordinates and projected onto the spherical harmonics. The resulting spectrum exhibits a peak at spherical harmonic degree } 100, which corresponds to typical cell diameters of about 40 Mm. Synthetic data were constructed and passed through the same analysis procedures to determine the actual spectrum required to reproduce the results. A good fit was obtained with a kinetic energy spectrum which peaks at } 100 and decreases exponentially out to } 500 with an e-folding range of } 90. A power law fit to the spectrum over this range in yields an exponent of about -2.75. No corrections for seeing were included in the analysis. Although the image was sampled at 8 arcsec resolution, the effects of seeing may alter the actual slope of the spectrum and make it somewhat flatter. The spectrum does not exhibit any evidence for a distinct mesogranulation component out to } 500 (corresponding to cell diameters of about 8 Mm). Title: Solar Oscillation Ring Diagrams from Mt. Wilson Full-Disk Magneto-Optical Dopplergrams Authors: Hill, Frank; Rhodes, Edward J.; Korzennik, Sylvain G.; Cacciani, Alessandro; Brown, Timothy M. Bibcode: 1991LNP...388..271H Altcode: 1991ctsm.conf..271H Three-dimensional power spectra of solar oscillations have been computed from moderate-resolution full disk Doppler images obtained with the Magneto-Optical Filter at Mt. Wilson. Slices of the spectra at constant frequency reveal the ring structures that are analogous to the ridges in two-dimensional spectra. Ring diagrams obtained at different heliographic positions show large differences in the structure of the rings. These variations can be attributed to the changing effective spatial resolution of the observations across the disk. After correction for this effect, and .for terrestrial seeing, the rings will be used to map the horizontal flows in the convection zone as a function of position and depth. Title: Observations of intermediate- and high-degree p-mode oscillations during sunspot cycles 21 and 22 Authors: Rhodes, E. J.; Cacciani, A.; Korzennik, S. G. Bibcode: 1991AdSpR..11d..17R Altcode: 1991AdSpR..11...17R Extensive time series of resolved solar images have been available for helioseismological studies since the late 1970s. We will first review the temporal coverage that has been built up over the past 11 years at several different observatories. Next, we will present examples of the frequencies, power levels, modal energies, and widths of solar intermediate-(5< l <120) and high-degree (120< l <600) p-modes which were obtained at the Mount Wilson Observatory's 60-Foot Solar Tower Telescope during the rising phase of the current sunspot cycle. We will demonstrate that the inclusion of frequency splittings from the high-degree p-modes has allowed us to demonstrate that the sun's internal equatorial angular velocity is not constant with radius but rather varies systematically with radius throughout the solar convection zone and below. Lastly, we will show that, by intercomparing many of the available p-mode frequency datasets, we have been able to confirm the recent suggestion by Libbrecht and Woodard /1/ that the frequencies of the intermediate-degree p-modes do vary systematically with varying levels of solar activity. In particular, we will demonstrate that such frequency shifts have been occurring in every year that observations have been obtained since 1980 and that such variations are also consistent with similar variations that have been recently noted in low-degree p-mode frequencies. Title: Measurements of Intermediate- and High-Degree (20<1<600) p-Mode Solar Oscillation Power and Energy Authors: Rhodes, Edward J.; Brown, Timothy M.; Cacciani, Alessandro; Korzennik, Sylvain G.; Ulrich, Roger K. Bibcode: 1991LNP...388..277R Altcode: 1991ctsm.conf..277R We present measurements of the total modal power and energy of both intermediate- and high-degree (20< l <600) solar p-mode oscillations which have been corrected to first order for the combined effects of atmospheric seeing, image motion due to imperfect tracking, and the point spread function of our optics. These power and energy estimates have been obtained from an average of 20 separate zonal l - n power spectra, which were obtained from observations obtained at the 60-Foot Solar Tower of the Mt. Wilson Observatory between July 1 and 20, 1988. The raw total power values were obtained from a least-squares fitting of Lorentzian profiles to the p-mode ridges in the average zonal power spectrum. As an initial method of correcting the observed power levels, we adopted the procedure described by Kaufman (1988) and deconvolved measurements of the observed limb profiles from one of our images using two slightly different theoretical unblurred limb profiles in order to obtain two estimates of the modulation transfer function (mtf) of our experiment. The corrected power values which resulted show systematic variations with both frequency and degree which are similar to those obtained by Kaufman. For example, between l = 100 and 600 our corrected power values drop by a factor of at least 4.5, although the magnitude of our correction becomes less certain as the degree is increased above 300. We also convert these power values into estimates of the total energy of the modes to show that the modal energies decrease by a factor of at least 15 over the same range in l. Even given the uncertainty of our correction at the higher degrees, the consistency of the l-dependent decrease in the modal energies with similar results by Kaufman (1990) suggests that, at least above l = 100, the modes are not in energy equipartition with turbulent convective eddies. Title: Further Evidence for Radial Variations in the Solar Equatorial Angular Velocity Profile Authors: Rhodes, Edward J.; Cacciani, Alessandro; Korzennik, Sylvain G.; Ulrich, Roger K. Bibcode: 1991LNP...388..285R Altcode: 1991ctsm.conf..285R One year ago we presented evidence that the rotationally-induced frequency splittings of intermediate- and high-degree sectoral p-mode oscillations vary systematically as a function of the degree, l, of the modes (Rhodes, Cacciani, and Korzennik, 1989. Recently, we confirmed the results presented there in three different ways. First, we extended our earlier 5-day sequence of Dopplergrams to one of 20 days which ran from July 1 through 20, 1988. We then repeated our earlier cross-correlation analysis using the intrinsically higher frequency resolution sectoral power spectra which resulted from the longer data string. This analysis also showed the same l-dependence of the frequency splittings which we had found in our earlier work. Second, we computed a separate pair of 1024-minute long sectoral power spectra for each of the 20 days and then averaged the 20 prograde and 20 retrograde spectra into two average sectoral spectra. We next computed the frequencies of the centers of both the prograde and retrograde sectoral ridges at each even-l by fitting Lorentzian profiles using a standard non-linear least-squares method and we then simply subtracted the central frequencies of the corresponding prograde and retrograde ridges at those same values of l. The splittings which resulted from averaging these frequency differences over both l and the radial overtone, n, showed the same l-dependence as did those obtained from the cross-correlation analysis. Thirdly, we computed Legendre coefficient expansions to the m - v frequency shifts of both the high- and low-resolution tesseral power spectra. We then normalized the sums of the odd Legendre expansion coefficients to obtain additional estimates of the sectoral frequency splittings. Finally, we carried out an inversion of the sectoral frequency splittings. This inversion shows a rapid rise in the solar equatorial angular velocity from its surface value to a value of 476 nHz at a depth of 0.07 to 0.08 solar radii below the photosphere. The inverted profile also shows that the inner half of the solar convection zone may be rotating at the magnetic feature rate and that the equatorial angular velocity decreases inwardly of the base of the convection zone to a depth of at least 0.50 solar radii. Title: Further Evidence for Radial Variations in the Solar Equatorial Angular Velocity Profile Authors: Rhodes, E. J., Jr.; Cacciani, A.; Korzennik, S.; Ulrich, R. K. Bibcode: 1990BAAS...22..896R Altcode: No abstract at ADS Title: Depth and Latitude Dependence of the Solar Internal Angular Velocity Authors: Rhodes, Edward J., Jr.; Cacciani, Alessandro; Korzennik, Sylvain; Tomczyk, Steven; Ulrich, Roger K.; Woodard, Martin F. Bibcode: 1990ApJ...351..687R Altcode: One of the design goals for the dedicated helioseismology observing state located at Mount Wilson Observatory was the measurement of the internal solar rotation using solar p-mode oscillations. In this paper, the first p-mode splittings obtained from Mount Wilson are reported and compared with those from several previously published studies. It is demonstrated that the present splittings agree quite well with composite frequency splittings obtained from the comparisons. The splittings suggest that the angular velocity in the solar equatorial plane is a function of depth below the photosphere. The latitudinal differential rotation pattern visible at the surface appears to persist at least throughout the solar convection zone. Title: Has the sun's internal rotation changed through this activity cycle ? Authors: Goode, P. R.; Dziembowski, W. A.; Rhodes, E. J., Jr.; Korzennik, S. Bibcode: 1990LNP...367..349G Altcode: 1990psss.conf..349G The internal rotation of the Sun is determined from each of the six available sets of solar oscillation splitting data. These data span this activity cycle and best sample the region near the base of the convection zone. Going inwards through the convection zone into the outer radiative interior, the robust results are a decrease in the rotation rate in the equatorial plane and a trend away from the surface-like differential rotation toward solid body rotation. In the equatorial plane of the radiative interior, the rotation rate seems to systematically increase through the solar cycle. If true, this suggests that the interior has a role in the activity cycle. Title: Contribution of High-Degree Frequency Splittings to the Inversions of the Solar Rotation Rate Authors: Korzennik, Sylvain G.; Cacciani, Alessandro; Rhodes, Edward J.; Ulrich, Roger K. Bibcode: 1990LNP...367..341K Altcode: 1990psss.conf..341K We present the contribution of high degree rotational splittings to the inversion of the internal rotation rate around the equator. The extention of the input data set to l of 500, allow us to improve the resolution of the solution mainly in the outermost 15% of the solar radius. The rotational profile obtained in the regions below the surface leads to an attractive picture that could reconcile different non-seismic estimates of the surface rotation rate. Title: Seismic Analysis of the Sun from Intermediate and High-Degree P-Modes Authors: Korzennik, Sylvain Gereon Bibcode: 1990PhDT........11K Altcode: Solar oscillations provide a unique tool to investigate the internal structure and dynamics of the Sun. While accurate measurements of the solar acoustic spectrum characteristics have been performed for low- and intermediate-degree modes, only a limited set of short time baseline measurements for high-degree modes has been available (l > 120). The purpose of this work is to provide an accurate and more reliable set of measurements for these high-degree modes. High spatial resolution (2.2 arc sec per pixel) full-disk dopplergrams of the solar surface have been acquired at the Mt. Wilson 60-feet solar tower during the summer of 1988, using a doppler analyzer based on the sodium magneto -optical filter. Twenty consecutive days of observations have been reduced to spherical harmonic coefficient time series, for degrees l<=q 600. The time series were then Fourier transformed in order to estimate the corresponding power spectra. From these power spectra, frequency splittings have been estimated for degree 20 <=q l <=q 600. At low and intermediate degree (l <=q 120), individual modes could be isolated, and hence reliable tesseral measurements have been obtained. At high-degree (l > 120), the presence of mode blending introduced systematic errors in the tesseral frequency splitting determination. The nature of these systematics has been carefully studied, but our simulations were unable to reproduce in detail the observed systematics, and therefore, an ad hoc procedure was developed to correct for them. Alternatively, sectoral frequency splittings, shown to be less sensitive to mode blending systematics, have provided a more reliable estimate of the frequency splitting for these high-degree modes. From collapsed < m = 0>^ectra modal frequencies, amplitudes and lifetimes have been estimated for 20 <=q l <=q 600. The required corrections for mode blending, point spread function attenuation, and finite observing run have been applied. These new measurements are compared with previous determinations and theoretical predictions. Finally, based on the frequency splittings obtained from the present study, as well as contemporaneous independent measurements, we have inferred the internal rotation rate as a function of depth in the equatorial regions, and discuss some of the implications of such a profile in relation to solar dynamo, global circulation and evolutionary models of rotating stars. Title: Evidence for Radial Variations in the Equatorial Profile of the Solar Internal Angular Velocity Authors: Rhodes, Edward J.; Cacciani, Alessandro; Korzennik, Sylvain G. Bibcode: 1990LNP...367..163R Altcode: 1990psss.conf..163R We present evidence that the solar internal angular velocity, at least as measured in the equatorial plane, shows systematic radial variations in the outer half (by radius of the solar interior. Specifically, we employ the rotationally-induced frequency splittings of both high- and intermediate-degree sectoral p-mode oscillations to demonstrate that the internal angular velocity rises inwardly from the observed spectroscopic rotation rate of the photospheric gas to a higher value that is at least equal to the observed rotation rate of sunspots, if not higher, in the outer third of the convection zone before decreasing inward of the convection zone to a value which is at least two percent below the photospheric gas rotation rate. By making the assumption that the observed splittings are sensitive to solar rotation at the midpoints of the p-mode eigenfunctions we obtain an angular velocity profile which rises from 452 nHz at the photosphere to 462 nHz at a depth of about five percent of the solar radius below the photosphere. A comparison of this inferred angular velocity profile with that obtained from a formal inversion of these splittings (which is reported elsewhere in these proceedings by Korzennik et al.) suggests that the angular velocity might actually exceed the magnetic rotation rate over much of the convection zone before decreasing inwardly toward the center of the sun. Title: Seismic Analysis of the Solar Interior. I. Can Opacity Changes Improve the Theoretical Frequencies? Authors: Korzennik, Sylvain G.; Ulrich, Roger K. Bibcode: 1989ApJ...339.1144K Altcode: The paper describes the application of seismic inverse theory to the deduction of properties of the solar interior using presently available measured frequencies of the solar oscillations. Only the solar opacity is included in this application. This study has used the spectral expansion method of Lanczos and Jackson to derive changes to the opacity which improve ageement between the theoretical and observed frequencies of oscillation. It is found that a family of opacity changes exists which yields models that improve the frequency agreement by amounts that are indistinguishable among the family members. Title: Evidence for Degree-Dependent Variations in the Frequency Splittings of Solar Sectoral p-Modes Authors: Rhodes, E. J., Jr.; Cacciani, A.; Korzennik, S. Bibcode: 1989BAAS...21..831R Altcode: No abstract at ADS Title: Spectrum Lifetime, and Rotation Rate of Supergranules Authors: Hathaway, D. H.; Rhodes, E. J., Jr.; Cacciani, A.; Korzennik, S. Bibcode: 1989BAAS...21..829H Altcode: No abstract at ADS Title: Solar Luminosity Oscillation Telescope (SLOT). Authors: Andersen, Bo Nyborg; Domingo, V.; Jones, A. R.; Korzennik, Sylvain G.; Jimenez, A.; Palle, Pere L.; Regulo, C.; Roca Cortés, Teodoro Bibcode: 1988ESASP.286..175A Altcode: 1988ssls.rept..175A Low degree l = 0-2 solar p-modes have been detected with the SLOT instruments at Izaña and Baja California. The main source of noise for these ground based observations is in the terrestrial atmosphere. However, the data acquisition system still has to have very slow intrinsic noise. The authors describe how this is achieved in the SLOT instruments. They also give a general description of the design and operating principles of the photometers and data acquisition system. Title: Measurement of the rotational frequency splitting of the solar five-minute oscillations from magneto-optical filter observations. Authors: Tomczyk, Steven; Cacciani, Alessandro; Korzennik, Sylvain G.; Rhodes, Edward J., Jr.; Ulrich, Roger K. Bibcode: 1988ESASP.286..141T Altcode: 1988ssls.rept..141T Observations of the solar five-minute oscillations in the photospheric velocity field were obtained during the summer of 1984 at the 60-foot solar tower of the Mt. Wilson Observatory with a magneto-optical filter. The magneto-optical filter employs magneto-optical effects in an atomic vapor to isolate narrow bandpasses in alternate wings of a spectral line. Time series of full disk velocity images having a resolution of about 10 arcseconds and a noise level of 15 m/s/pixel were obtained on 92 days between the months of May and September of 1984. A subset of two time series from this data of 16 and 19 days duration having a total of 25744 doppler images were analyzed to provide estimates of the rotational frequency splitting for spherical harmonic degrees between 5 and 120. The results of this analysis indicate a decrease in the rate of solar rotation with increasing depth inside the sun. Also, a decrease in the rate of differential rotation with increasing depth is observed. Title: Inversion of the solar rotation rate versus depth and latitude. Authors: Korzennik, Sylvain G.; Cacciani, Alessandro; Rhodes, Edward J., Jr.; Tomczyk, Steven; Ulrich, Roger K. Bibcode: 1988ESASP.286..117K Altcode: 1988ssls.rept..117K The authors have used three different inversion techniques to compute the internal solar rotation rate from several sets of n-averaged frequency splittings. They have used an iterative variation of the spectral expansion method, the optimal averaging kernel method and a piecewise constant constrained least square method to invert the data. Each computation was carried out independently. While they present similar trends, each of the solutions differs in detail. A consistent feature in all the inversions is the disappearance of differential rotation below the base of the convection zone. Also, a strong differential signature in the deeper part of the convection zone is present in most of the solutions. A slow decrease of the rotation rate with depth for the equatorial and mid-latitude curves is significant in the spectral expansion and the least square results but only marginally apparent in the averaging kernel results. Title: Radial and latitudinal gradients in the solar internal angular velocity. Authors: Rhodes, Edward J., Jr.; Cacciani, Alessandro; Korzennik, Sylvain G.; Tomczyk, Steven; Ulrich, Roger K.; Woodard, Martin F. Bibcode: 1988ESASP.286...73R Altcode: 1988ssls.rept...73R The authors recently presented the results of an analysis of the frequency splittings of intermediate-degree (3 < degree ≤ 170) p-mode oscillations which were obtained from a 16-day subset of our 1984 Mt. Wilson 60-foot tower observations. These results showed evidence for both radial and latitudinal gradients in the solar internal angular velocity. In particular, the results indicated that, from 0.6 Rsun to 0.95 Rsun, the solar internal angular velocity increases systematically from 440 to 463 nHz, corresponding to a positive radial gradient of ≍66 nHz/Rsun for that portion of the solar interior. A previous analysis indicated that the latitudinal differential rotation gradient which is seen at the solar surface persists throughout the convection zone, although there was some indication that the differential rotation might disappear entirely below the base of the convection zone. Here the authors extend their previous analysis to include comparisons with additional observational studies and they also present comparisons between our earlier results and the results of additional inversions of several of the observational datasets. All of these comparisons reinforce the previous conclusions regarding the existence of radial and latitudinal gradients in the internal angular velocity. Title: Initial high-degree p-mode frequency splittings from the 1988 Mt. Wilson 60-foot tower solar oscillation program. Authors: Rhodes, Edward J., Jr.; Cacciani, Alessandro; Korzennik, Sylvain G. Bibcode: 1988ESASP.286...81R Altcode: 1988ssls.rept...81R The authors present here the initial frequency splitting results of solar p-mode oscillations which they have obtained from their 1988 helioseismology at the Mt. Wilson Observatory. These frequency splittings correspond to the rotational splittings of sectoral harmonics which range in degree between 10 and 598. They were obtained from a cross-correlation analysis of the prograde and retrograde portions of a two-dimensional (l-ν) power spectrum. This power spectrum was computed from an eight-hour sequence of full-disk Dopplergrams which were obtained on July 2, 1988, at the 60-foot tower telescope with a Na magneto-optical filter and a 1024×1024 pixel CCD camera. These frequency splittings have an inherently larger scatter than did the splittings obtained from earlier 16-day power spectra. Consequently, the best one can say now is that these splittings are consistent with an internal solar rotational velocity which is independent of radius along the equatorial plane. The normalized frequency splittings averaged 449±3 nHz, a value which is very close to the observed equatorial rotation rate of the photospheric gas of 451.7 nHz. Title: Diurnal photometric conditions at Teide observatory and long-term solar irradiance variations Authors: Andersen, B.; Domingo, V.; Jiménez, A.; Jones, A.; Korzennik, S.; Pallé, P. L.; Pérez Hernández, F.; Régulo, C.; Roca Cortés, T.; Tomás, L. L. Bibcode: 1988SoPh..116..391A Altcode: Monochromatic extinction coefficients at four wavelengths have been obtained over a period of more than two years at the Observatorio del Teide (Izaña Tenerife) using a full disc, direct sunlight, quadruple photometer devoted to the detection of integral luminosity oscillations of the Sun. The mean extinction coefficients (0.13 at 500 nm) show a seasonal variation of about 15%, the best atmospheric conditions being in winter and autumn. Moreover, in anyone day the extinction coefficient in the afternoon is always lower than the one in the morning by ∼ 7%. A one-year period fluctuation, with an amplitude of ∼ 0.035 mag, has been identified in the instrumental magnitudes outside the atmosphere, and is interpreted as the variation produced by the different Sun-Earth distance from winter to summer. Finally, the study made to detect periodic time fluctuations in both, Sun's magnitude and extinction coefficients, has given null results at levels of ∼ 0.04 and ∼ 1.8%, respectively. Title: On the Constancy of Intermediate-Degree p-Mode Frequencies during the Declining Phase of Solar Cycle 21 Authors: Rhodes, Edward J., Jr.; Woodard, Martin F.; Cacciani, Alessandro; Tomczyk, Steven; Korzennik, Sylvain G.; Ulrich, Roger K. Bibcode: 1988ApJ...326..479R Altcode: A comparison of two sets of frequencies of intermediate-degree (6 ≤ l ≤ 89) solar p-mode oscillations obtained in late 1981 and in mid-1984 shows agreement at the level of 0.02 μHz, or better than one part in 105. In particular, the frequencies of 573 modes obtained at the South Pole during 1981 December 24 - 25, (reported by Duvall, Harvey, and Pomerantz in 1987) were compared with the frequencies of the same modes as observed at the Mount Wilson Observatory 60 foot Solar Tower from 1984 July 29 through August 13. It is concluded that the data are consistent with no change in intermediate-degree p-mode frequencies between late 1981 and mid-1985. Title: Measurements of Solar Internal Rotation Obtained with the Mt-Wilson 60-FOOT Solar Tower Authors: Rhodes, E. J., Jr.; Cacciani, A.; Woodard, M.; Tomczyk, S.; Korzennik, S.; Ulrich, R. K. Bibcode: 1988IAUS..123...41R Altcode: The authors have obtained estimates of the solar internal rotational velocity from measurements of the frequency splittings of p-mode oscillations. Specifically, they have analyzed a 10-day time series of full-disk Dopplergrams obtained during July and August 1984 at the 60-Foot Tower Telescope of the Mt. Wilson Observatory. Title: Earthbased Observations of Solar Luminosity Oscillations Authors: Jimenez, A.; Palle, P. L.; Perez-Hernandez, F.; Regulo, C.; Roca-Cortes, T.; Domingo, V.; Korzennik, S. Bibcode: 1988IAUS..123...71J Altcode: Earth based multichannel photometry of integral sunlight has been obtained at Izaña (Tenerife) during 1984 - 1986. Power spectra of the solar luminosity variations of individual days show power in the 5 minute interval above noise at a level comparable to SMM data. When combining contigous days of data the signature of p mode solar oscillations spectrum appears, although individual peak identification is difficult. Title: Constancy of Intermediate-degree p-Mode Frequencies During the Declining Phase of Solar Cycle 21 Authors: Rhodes, E. J., Jr.; Woodard, M. F.; Cacciani, A.; Tomczyk, S.; Korzennik, S.; Ulrich, R. K. Bibcode: 1987BAAS...19Q.933R Altcode: No abstract at ADS Title: Angular Velocity of the Solar Interior Obtained by an Asymptotic Inversion of P-Mode Frequency Shifts Authors: Woodard, M. F.; Rhodes, E. J., Jr.; Tomczyk, S.; Korzennik, S.; Cacciani, A.; Ulrich, R. K. Bibcode: 1987BAAS...19..934W Altcode: No abstract at ADS Title: Estimates of the solar internal angular velocity obtained with the Mt. Wilson 60-foot solar tower Authors: Rhodes, Edward J., Jr.; Cacciani, Alessandro; Woodard, Martin; Tomczyk, Steven; Korzennik, Sylvain; Ulrich, R. K. Bibcode: 1987ASSL..137...75R Altcode: 1987isav.symp...75R Estimates are obtained of the solar internal angular velocity from measurements of the frequency splittings of p-mode oscillations. A 16-day time series of full-disk Dopplergrams obtained during July and August 1984 at the 60-foot tower telescope of the Mt. Wilson Observatory is analyzed. Power spectra were computed for all of the zonal, tesseral, and sectoral p-modes from l = 0 to 89 and for all of the sectoral p-modes from l = 90 to 200. A mean power spectrum was calculated for each degree up to 89. The frequency differences of all of the different nonzonal modes were calculated for these mean power spectra. Title: Ground-based measurements of solar intensity oscillations Authors: Jimenez, A.; Palle, P. L.; Roca Cortes, T.; Domingo, V.; Korzennik, S. Bibcode: 1987A&A...172..323J Altcode: Ground-based multichannel photometry of integral sunlight has been obtained at Izaña (Tenerife) during three months in 1984 with a photometer built at ESTEC. Power spectra of solar irradiance variations of individual days show power in the 5 min band just above noise at a level comparable to the one found from the SMM data (Woodard and Hudson, 1983). Previous similar ground work had never achieved the signal level required at the 5 min interval. When combining the best 7 contiguous days of data, the signature of p mode solar oscillations spectra appears, but individual identification is difficult due to a low signal-to-noise ratio. Title: Inversion of Perturbed Solar Models for Improved Solar Oscillation Frequencies Agreement Authors: Korzennik, S. G.; Yaari, A.; Ulrich, R. K. Bibcode: 1986BAAS...18..990K Altcode: No abstract at ADS Title: Evidence for Radial Gradients in the Solar Internal Rotational Velocity Authors: Rhodes, E. J., Jr.; Tomczyk, S.; Woodard, M. F.; Cacciani, A.; Korzennik, S.; Ulrich, R. K. Bibcode: 1986BAAS...18Q1010R Altcode: No abstract at ADS