Simulations of gas sloshing in galaxy cluster Abell 2052

TL;DR

This study uses hydrodynamical simulations to understand the gas sloshing and spiral structures in galaxy cluster Abell 2052, revealing possible collision histories and identifying a related galaxy group.

Contribution

It presents the first detailed hydrodynamical N-body simulations reproducing the observed gas sloshing features in Abell 2052 and constrains its dynamical history.

Findings

Two collision scenarios reproduce the spiral structure.

The older scenario predicts a perturber 2 Mpc away.

An optical galaxy group matches the predicted perturber location.

Abstract

The intracluster plasma of Abell 2052 exhibits in X-rays a spiral structure extending more than 250 kpc, which is comprised of cool gas. This feature is understood to be the result of gas sloshing caused by the off-axis collision with a smaller subcluster. We aim to recover the dynamical history of Abell 2052 and to reproduce the broad morphology of the spiral feature. To this end, we perform hydrodynamical $N$-body simulations of cluster collisions. We obtain two regimes that adequately reproduce the desired features. The first scenario is a close encounter and a recent event (0.8 Gyr since pericentric passage), while the second scenario has a larger impact parameter and is older (almost 2.6 Gyr since pericentric passage). In the second case, the simulation predicts that the perturbing subcluster should be located approximately 2 Mpc from the centre of the major cluster. At that position, we are able to identify an observed optical counterpart at the same redshift: a galaxy group with $M_{500} = (1.16 \pm 0.43) \times 10^{13} M_{\odot}$.