NOAO >   Observing Info >   Approved Programs >   2009B-0282

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Proposal Information for 2009B-0282


PI: Mark A Norris, UNC - Chapel Hill, manorris@physics.unc.edu
Address: Department of Physics and Astronomy, CB 3255, Phillips Hall, Chapel Hill, North Carolina 27599-3255, USA

CoI: Sheila Kannappan, UNC - Chapel Hill

Title: Unified Analysis of Spheroid and Disk Dynamics in S0s

Abstract: Spiral and elliptical galaxies obey fundamental scaling relations between their kinematic and structural properties, which place strong constraints on their formation histories. Attempts to place S0s in such relations have proven less successful because their stellar motions combine both rotation V_* and dispersion \sigma$_* components, which are difficult to unify into a single characteristic velocity equivalent to cold gas rotation V_g. In approved program 09A-0297 we have taken the first steps toward an empirical calibration of (V_*, \sigma$_*^c) vs. V_g using spectroscopy reaching significantly deeper than existing surveys (e.g., SAURON). We here propose to extend this analysis to the 13 S0s in our sample of 24 that have logM_* < 10.5, using the newly commissioned 1200 line grating on SOAR's Goodman Spectrograph. Significant diversity in the kinematic properties of S0s appears in this mass regime, as exemplified by the increasing importance of rotational support and rising frequency of pseudobulges. From these data we aim to construct a simple estimator of V_g that could be used given only shallower stellar absorption line data (V_*, \sigma$_*^c) and information such as stellar mass, bulge-to-disk ratio, and bulge profile shape.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



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