The Evolution of the Star Formation Activity in Galaxies and Its Dependence on Environment

Abstract

ApJ, in press We study how the proportion of star-forming galaxies evolves between z = 0.8 and z = 0 as a function of galaxy environment, using the [OII] line in emission as a signature of ongoing star formation. Our high-z dataset comprises 16 clusters, 10 groups and another 250 galaxies in poorer groups and the field at z = 0.4 − 0.8 from the ESO Distant Cluster Survey, plus another 9 massive clusters at similar redshifts. As a local comparison, we use samples of galaxy systems selected from the Sloan Digital Sky Survey at 0.04 < z < 0.08. At highz most systems follow a broad anticorrelation between the fraction of star-forming galaxies and the system