Assigned ID: 483 ----- Submission 1 (Fri Jan 21 22:46:55 GMT 2005) ----- The evolution of massive galaxy clusters provides a unique opportunity to probe the formation of large scale structures and environmental effects on the stars and galaxies within them. We propose a uniform analysis of archival HST ACS and Chandra ACIS observations of 15-20 galaxy clusters at redshifts 0.15-1.3 with the specific goal of tracing the evolution of clusters that will have Coma-like masses in the present day. Our approach combines hydrodynamical simulations, X-ray images and temperatures, and optical observations. We will choose our sample by matching broad cluster properties such as X-ray temperature and luminosity measured via the Chandra observations to hydrodynamical simulations of clusters which evolve to Coma's properties at z=0. Thus we use the properties of the dominant baryon reservoir to select clusters forming a consistent evolutionary sequence. By confining our sample to clusters along this sequence, our program is in distinct contrast with previous studies which generally highlight very massive systems at high redshift- objects which will not evolve to any known present-day cluster. This previous selection bias may mask any actual evolution in the cluster galaxies that occurs as the clusters form. ACS observations of our carefully selected sample will allow us to quantitatively inventory the cluster galaxy population and trace galaxy evolution along with the intracluster gas in these clusters as they evolve from relatively low-mass, shallow potential-well structures to the typical rich clusters of today.

GALAXIES 12 94920 false 0.0 false false false false false SUPPORTED