X-ray observations of the merging cluster CIZA J2242.8+5301

TL;DR

This study presents XMM-Newton X-ray observations of the merging galaxy cluster CIZA J2242.8+5301, focusing on the northern radio relic, and discusses temperature measurement discrepancies with previous Suzaku data.

Contribution

First detailed X-ray analysis of CIZA J2242.8+5301's northern relic using XMM-Newton, addressing temperature measurement challenges in cluster outskirts.

Findings

Measured a 55% temperature difference behind the relic compared to Suzaku.

Analyzed reasons for temperature discrepancy and measurement reliability.

Discussed implications for X-ray observations of cluster outskirts.

Abstract

Multiwavelength studies of radio relics at merger shocks set powerful constraints on the relics origin and formation mechanism. However, for X-ray observations, a main difficulty is represented by the low X-ray surface brightness far out in the cluster outskirts, where relics are typically found. Here, we present XMM-Newton results from a 130-ks observation of CIZA J2242.8+5301, a cluster at z=0.19 that hosts a double radio relic. We focus on the well-defined northern relic. There is a difference of ~55% between the temperature we measure behind the relic, and the temperature measured with Suzaku. We analyse the reasons for this large discrepancy, and discuss the possibility of reliably measuring the temperature beyond the northern relic.