Exemplary Merging Clusters: Weak-lensing and X-ray Analysis of the Double Radio Relic Merging Galaxy Clusters MACS 1752.0+4440 and ZWCL 1856.8+6616

TL;DR

This study uses weak-lensing and X-ray data to analyze two rare double radio relic galaxy clusters, revealing their merger dynamics, mass ratios, and evolutionary stages, which enhances understanding of cluster formation and dark matter.

Contribution

It provides detailed weak-lensing and X-ray analysis of two double radio relic clusters, offering new insights into their merger scenarios and evolutionary phases.

Findings

Both clusters are major mergers with near equal mass ratios.

The clusters exhibit similar gas and mass distribution features despite different total masses.

ZWCL1856.8+6616 is likely in a later merger phase than MACSJ1752.0+4440.

Abstract

The investigation of merging galaxy clusters that exhibit radio relics is strengthening our understanding of the formation and evolution of galaxy clusters, the nature of dark matter, the intracluster medium, and astrophysical particle acceleration. Each merging cluster provides only a single view of the cluster formation process and the variety of merging clusters is vast. Clusters hosting double radio relics are rare and extremely important because they allow tight constraints on the merger scenario. We present a weak-lensing and X-ray analysis of MACSJ1752.0+4440 ($z$=0.365) and ZWCL1856.8+6616 ($z$=0.304), two double radio relic clusters. Our weak-lensing mass estimates show that each cluster is a major merger with approximately 1:1 mass ratio. The total mass of MACSJ1752.0+4440 (ZWCL1856.8+6616) is $M_{200}=14.7^{+3.8}_{-3.3}\times10^{14}\ $M$_\odot$ ($M_{200}=2.4^{+0.9}_{-0.7}\times10^{14}\ $M$_\odot$). We find that these two clusters have comparable features in their weak-lensing and gas distributions, even though the systems have vastly different total masses. From the likeness of the X-ray morphologies and the remarkable symmetry of the radio relics, we propose that both systems underwent nearly head-on collisions. However, revelations from the hot-gas features and our multiwavelength data analysis suggest that ZWCL1856.8+6618 is likely at a later merger phase than MACSJ1752.0+4440. We postulate that the SW radio relic in MACSJ1752.0+4440 is a result of particle re-acceleration.