NOAO >   Observing Info >   Approved Programs >   2010B-0588

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Proposal Information for 2010B-0588


PI: R. Michael Rich, UCLA, rmr@astro.ucla.edu
Address: Dept. of Physics and Astroomy, PAB, 430 Portola Plaza, Box 951547, Los Angeles, CA 90095-1547, USA

CoI: Andreas Koch, University of Leicester

Title: The C/M Star Ratio in M31 Halo Fields from Narrow-Band Imaging

Abstract: We propose to measure the C/M ratio in a range of M31 halo fields that sample a variety of substructures. While the C/M ratio has been measured for the disk of M31 and for a number of its satellites, this would be the first investigation of the M31 halo, to our knowledge. An important goal is to determine whether the Giant Stream (Ibata et al. 2001) and its shells, have a unique C/M ratio that might constrain the star formation history and nature of the galaxy that was ingested. We also propose to image major plumes and struuctures in the inner halo. A secondary goal is to confirm the surprising finding by Koch & Rich (2010) that the M31 halo has a generally very low C/M ratio. This finding challenges the LCDM paradigm that halos should be comprised of substructure consisting of ingested galaxies.


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



NOAO >   Observing Info >   Approved Programs >   2010B-0588

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