Cluster Core Heating from Merging Subclusters

TL;DR

This paper investigates how galaxy cluster core heating from gas sloshing during mergers can offset cooling, analyzing the effects of merger parameters and ICM viscosity through simulations.

Contribution

It provides the first systematic simulation-based analysis of sloshing-induced heating across various merger scenarios and ICM viscosities.

Findings

Sloshing can partially offset cooling in cluster cores.

Higher ICM viscosity reduces the effectiveness of sloshing heating.

Merger parameters significantly influence the heating efficiency.

Abstract

Though feedback from central active galactic nuclei provides an attractive solution to the problem of overcooling in galaxy cluster cores, another possible source of heating may come from ``sloshing'' of the cluster core gas initiated by mergers. We present a set of simulations of galaxy cluster mergers with subclusters in order to determine the amount of heating provided by the mechanism of sloshing, exploring a parameter space over mass ratio, impact parameter, and viscosity of the intracluster medium (ICM). Our results show that for sloshing caused by mergers with gasless subclusters cooling may be partially offset by heating from sloshing, but this mechanism is less effective if the ICM is viscous.