NOAO >   Observing Info >   Approved Programs >   2013A-0479

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Proposal Information for 2013A-0479


PI: Vandana Desai, Caltech, desai@ipac.caltech.edu
Address: IPAC, 1200 East California Blvd, Pasadena, CA 91125, USA

CoI: Gabriella De Lucia, INAF-Osservatorio Astronomico di Trieste
CoI: Bianca Poggianti, INAF-Osservatorio Astronomico di Padova
CoI: Gregory Rudnick, University of Kansas
CoI: Dennis Just, Steward Observatory
CoI: Alfonso Aragon-Salamanca, University of Nottingham
CoI: Rose Finn, Siena College
CoI: Pascale Jablonka, EPFL

Title: The role of post-starburst galaxies in the growth of the red sequence in intermediate redshift clusters

Abstract: Most galaxies occupy two regions in color-magnitude space: the red sequence and the blue cloud. The traditional interpretation of the tightness of the red sequence is that these galaxies formed at high redshift (z > 2). However, using data from the EDisCS cluster sample, we have found that many of the faint (sub-L_\ast) galaxies in clusters have appeared on the red sequence relatively recently (z < 1). These newcomers must have originated in the blue cloud and migrated to the red sequence after a truncation in star formation. If so, these galaxies must have gone through a post-starburst (k+a) phase, with spectra characterized by deep Balmer absorption from A stars created in the recent (<1.5 Gyr) past, but without strong emission lines because there is no \textitcurrent star formation. We propose deep GMOS spectroscopy of sub-L_\ast galaxies in four z~0.5 clusters to search for and characterize this post-starburst population. These observations will constrain the range of star formation histories of the passive cluster population and the physical processes driving their evolution onto the red sequence.


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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