Physics of the intra-cluster medium at high redshift

Abstract

While the concept of "clustering" primarily refers to galaxies, the fact is that galaxies can be neglected - at least in terms of mass - when considering the continuous competition between accretion and relaxation processes of dark matter and gas, which control the dynamical life of galaxy clusters. Gravity is certainly the driving force in cluster formation and evolution, but is not sufficient to explain in detail the properties of the ICM brought to light by the most recent X-ray data: non thermal phenomena revealed by radio observations, micro-physics and feedback from galaxies play also a key role. From numerical simulations constrained by observations of the intra-cluster medium at low z, we attempt to extrapolate properties back in the time when density contrasts in the universe were much less pronounced.