Fast simulations of gas sloshing and cold front formation

TL;DR

This paper introduces a rapid simulation method for galaxy cluster mergers using a rigid potential approximation, effectively modeling gas sloshing and cold front formation with minor artifacts.

Contribution

The authors develop and validate a simplified, fast simulation approach for minor galaxy cluster mergers that approximates dark matter dynamics with a rigid potential.

Findings

The method accurately reproduces gas sloshing features.

Temperature outside cold fronts is slightly overestimated.

Outward cold front motion is delayed by about 200 Myr.

Abstract

We present a simplified and fast method for simulating minor mergers between galaxy clusters. Instead of following the evolution of the dark matter halos directly by the N-body method, we employ a rigid potential approximation for both clusters. The simulations are run in the rest frame of the more massive cluster and account for the resulting inertial accelerations in an optimised way. We test the reliability of this method for studies of minor merger induced gas sloshing by performing a one-to-one comparison between our simulations and hydro+N-body ones. We find that the rigid potential approximation reproduces the sloshing-related features well except for two artefacts: the temperature just outside the cold fronts is slightly over-predicted, and the outward motion of the cold fronts is delayed by typically 200 Myr. We discuss reasons for both artefacts.