PI: Mauro Giavalisco, University of Massachusetts Amherst, firstname.lastname@example.org
Address: Astronomy Department, 710 N. Pleasant St., LGRT-B 520, Amherst, MA 01002, U.S.A.
CoI: Elena Tundo, University of Nottingham, UK
CoI: Paolo Tozzi, INAF - Arcertri Observatory, Italy
CoI: Stuart Muldrew, University of Nottingham, UK
CoI: Piero Rosati, ESO, Garching bei Munchen, Germany
Title: Probing Environmental Effects on Galaxy Evolution in Groups and Clusters at 0.3<z<0.8
Abstract: We request 5 nights at the 4-meter telescope with Mosaic for multi–-band imaging (U_ngriz) of groups and clusters of galaxies at 0.3<z<0.8 from a new X–-ray selected sample with a uniquely wide dynamic range of X–-ray luminosity. Goals of the observations are to identify cluster members down to L/L^*~ 0.2 at z~ 0.8 from accurate photometric redshifts (the available SDSS photometry is too shallow for anything but the brightest members), and measure their stellar mass, approximate age, star formation rate and dust obscuration from high-quality SED fits to spectral population synthesis models to study environmental dependence of galaxy evolution. At redshift z\lesssim 1 the bulk of the stellar mass of bright galaxies (e.g. L/L*>0.2) is assembled and interactions and merging remain the main drivers of evolution. Exactly how the rate of merging , both minor and major ones, and the kinematics of interactions result in the formation of modern galaxies, remain to be detailed, however. Our clusters spans over 4 orders of magnitude in X-ray luminosity, from groups to massive clusters, covering the full spectrum of overdensities. By allowing us to study the variations of galaxies' properties and spatial abundance with both the local and global environment from z~ 0.8 to the present, the proposed data will help clarify how the modern population of bright galaxies has evolved during the second half of the Hubble time.
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360