Dynamical evolution of clusters of galaxies

Abstract

Evidence is presented for a recent evolution of the relaxation processes in clusters of galaxies. The criteria of the cluster relaxation used are the cluster ellipticity, the ICM temperature and X-ray cluster luminosity. We find evidence of all three indicators evolving with redshift for z ≤ 0:15. This result supports the view that clusters have mostly stopped undergoing mergers and accreting matter, as expected in a lowΩm Universe, and are now in the process of gravitational relaxation, which reduces their attening, their ICM temperature (shock heated during the merging phase), and their X-ray luminosity.