CHEX-MATE: New detections and properties of the radio diffuse emission in massive clusters with MeerKAT

TL;DR

This paper presents new MeerKAT radio observations of 21 massive galaxy clusters, detecting multiple diffuse radio sources, confirming scaling relations, and demonstrating the telescope's capability to explore low-power relics, advancing understanding of non-thermal phenomena.

Contribution

The study provides the first detections of new radio halos and relics in a sample of massive clusters using MeerKAT, and analyzes their properties and scaling relations, highlighting the telescope's sensitivity.

Findings

Detected 2 new halos and 1 new relic.

Confirmed radio halo power-mass correlation.

Extended the exploration of low-power relics.

Abstract

Modern radio telescopes are revolutionising our understanding of non-thermal phenomena in galaxy clusters, collecting large samples of extended sources with unprecedented sensitivity and angular resolution. In this work, we present novel MeerKAT observations for a sample of 21 galaxy clusters that are part of the CHEX-MATE project. These systems were selected based on their high mass and displaying signs of dynamical activity. Thanks to the high-quality data at hand, we were able to detect extended radio emission in every target considered. We report two new halos, one new relic, and two new candidate relics. We also confirm a previous candidate halo and two candidate relics. After investigating the scaling relations with the cluster properties, we confirmed the presence of a radio halo power-mass correlation and relate it to a higher radio halo emissivity in more massive clusters. For radio relics, we highlight the MeerKAT capabilities to significantly extend the depth of radio observations to a new, unexplored field of low-radio power sources ($\lesssim 10^{23} ~ {\rm W~Hz^{-1}} $ at 1.28 GHz). Thanks to such high-sensitivity data, we have found that the radio relic power can be characterised by a wide range of values for a given cluster mass and relic size. Ultimately, we discuss how current radio observations, in combination with large radio surveys, are increasingly capable of testing numerical simulation predictions and coming close to performing direct comparisons with their data, enabling new insights on the evolution of radio relics.