Thermo-dynamic and chemical properties of the intra-cluster medium

Abstract

Aims: We aim to provide constraints on evolutionary scenarios in clusters. One of our main goals is to understand whether, as claimed by some, the cool core/non-cool core division is established once and for all during the early history of a cluster.
Methods: We employ a sample of ≃60 objects to classify clusters according to different properties. We characterize cluster cores in terms of their thermo-dynamic and chemical properties and clusters as a whole in terms of their dynamical properties.
Results: We find that I) the vast majority of merging systems feature high-entropy cores (HEC) and II) objects with lower entropy cores feature more pronounced metallicity peaks than objects with higher entropy cores. We identify a small number of medium (MEC) and high (HEC) entropy core systems that, unlike most other such objects, feature a high central metallicity. The majority of these outliers are mergers, i.e. systems far from their equilibrium configuration.
Conclusions: We surmise that medium (MEC) and high (HEC) entropy core systems with a high central metallicity have recently evolved from low-entropy core (LEC) clusters that have experienced a heating event associated to AGN or merger activity.