NOAO >   Observing Info >   Approved Programs >   2009A-0432

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Proposal Information for 2009A-0432


PI: Ronald Marzke, San Francisco State University, marzke@sfsu.edu
Address: Physics Department, 1600 Holloway Ave., San Francisco, CA 94132, USA

CoI: Ann Hornschemeier, NASA/GSFC
CoI: Russell Smith, University of Durham
CoI: Neal Miller, Johns Hopkins University
CoI: Michael Hudson, University of Waterloo
CoI: Harry Ferguson, STScI
CoI: Terry Bridges, Anglo-Australian Observatory
CoI: John Lucey, University of Durham
CoI: Brent Tully, University of Hawaii
CoI: David Carter, Liverpool John Moores University
CoI: Mustapha Mouhcine, Liverpool John Moores University
CoI: Neil Trentham, Cambridge University
CoI: Nelson Caldwell, Harvard-Smithsonian Center for Astrophysics

Title: The Faint End of the Red Sequence in the Coma Cluster: A Comprehensive Spectroscopic Survey from the Core to the Virial Radius

Abstract: We request two nights to complete our deep, wide-field spectroscopic survey of the Coma cluster using the MMT with Hectospec. In 2007A, we obtained 4788 spectra to measure the luminosity function and the stellar populations of Coma cluster galaxies. The 2007A observations were limited to two fields, one in the core and the other roughly a degree to the southwest in a region dominated by the single group associated with NGC 4839. Spectral indices of a high-S/N subsample drawn from these two fields show that the mean age of the low-luminosity galaxies is lower in the outskirts of the cluster than in the cluster center. We requested and were awarded four nights in 2008A to determine whether this radial decline in galaxy ages is a global feature of the Coma infall region and to place the luminosity function measured in the infall region on the same statistical footing as the luminosity function measured in the core. Because of unfavorable scheduling and poor weather, we obtained less than half of the observations awarded in 2008A. Here we request time to complete the survey.


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