Simulating Galaxies and Galaxy Clusters

The X-ray luminosities of the hot halo gas around simulated, Milky Way like disk galaxies have been determined, as a function of redshift. The X-ray luminosity increases significantly with redshift, in some cases as much as a factor 30 going from z=0 to 2. Consequently, the optimal detection redshift can be >~0.5. Results of fully cosmological simulations of galaxy groups and clusters, incorporating star formation, chemical evolution with non-instantaneous recycling, metal-dependent radiative cooling, galactic super-winds and thermal conduction are presented. X-ray luminosities at z=0 are somewhat high and central entropies somewhat low compared to observations. This is likely a combined effect of chemical evolution and metal-dependent, radiative cooling. Central ICM abundance profiles are somewhat steep, and the observed level of ICM enrichment can only be reproduced with IMFs more top-heavy than the Salpeter IMF. In agreement with observations it is found that the iron in the ICM is in place already at z~1. The [Si/Fe] of the ICM decreases with time, and increases slightly with radius at a given time. The cluster galaxies match the observed "red sequence" very well, and the metallicity of cluster galaxies increases with galaxy mass, as observed.

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