Cosmic downsizing at z~1 from RCS galaxy clusters
Abstract
We present deep Js and Ks imaging of 14 galaxy clusters at z~1 that were discovered in the Red-Sequence Cluster Survey (RCS) and followed up using ISAAC/VLT. We are interested in studying the galaxy luminosity function at z ~ 1 and compare it to local estimations, for getting some insight into the dominant physical processes that regulate galaxy formation and evolution in dense environments. The Ks-band luminosity function for the composite cluster was derived down to M*+2.5 by means of applying an statistical background subtraction method, and can be described by a Schechter function with Ks*=17.86 and alpha = -1.15 by leaving all parameters free. We fixed the faint end slope to alpha=-0.9 for comparing our LF to local estimations (De Propris et al. 1999) and for studying the evolution of Ks* as a function of redshift. Using passive evolution models of Kodama & Arimoto (1997) we concluded that the mean formation redshift of cluster galaxies is z_f=3. Furthermore, we built the color-magnitude diagram for the background subtracted composite cluster and it shows a truncation of the red-sequence below M_V=-20.0, supporting the downsizing scenario first noted by Cowie et al. (1996)
- Publication:
-
VI Reunion Anual Sociedad Chilena de Astronomia (SOCHIAS)
- Pub Date:
- 2007
- Bibcode:
- 2007soch.conf...38M
- Keywords:
-
- Galaxy clusters;
- High-redshift;
- Evolution;
- Luminosity function