Why Do Only Some Galaxy Clusters Have Cool Cores

摘要: Flux-limited X-ray samples indicate that about half of rich galaxy clusters have cool cores. Why do only some cores while others not? In this paper, cosmological N-body + Eulerian hydrodynamic simulations, including radiative cooling and heating, are used to address question as we examine the formation evolution core (CC) noncool (NCC) clusters. These adaptive mesh refinement simulations produce both CC NCC in same volume. They a peak resolution 15.6 h−1 kpc within (256 Mpc)3 box. Our suggest there important evolutionary differences between their counterparts. Many numerical accreted mass more slowly over time grew enhanced CCs via hierarchical mergers; when late major mergers occurred, survived collisions. By contrast, experienced early destroyed embryonic produced conditions prevented reformation. As result, our predict observationally testable distinctions properties beyond regions particular, find versus shapes surface brightness profiles, temperatures hardness ratios cores, distribution masses, supercluster environs. It also appears no closer hydrostatic equilibrium than clusters, an issue for precision cosmology measurements.