QSO Absorption Lines and the Halos of Cluster Galaxies

Abstract

In the local universe, most QSO absorption-lines seem to arise from gas in extended ~ 100 kpc halos around spiral galaxies. We present evidence that at high redshift, at least some absorption lines come from different sources: the gas is associated not with spiral galaxy halos but with the intra-cluster medium of proto-galaxy clusters. This gas, which is neutral and lumpy, may form a true intra-cluster medium, but it is more likely to be associated with the halos of young elliptical galaxies. This gas may turn into the X-ray emitting intra-cluster medium of present-day rich galaxy clusters. Show more