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

¹ DIFA – Università di Bologna Via Gobetti 93/2 I-40129 Bologna, Italy
² INAF – IASF Milano Via A. Corti 12 20133 Milano, Italy
³ DiSAT, Università degli Studi dell’Insubria Via Valleggio 11 I-22100 Como, Italy
⁴ INAF, Osservatorio di Astrofisica e Scienza dello Spazio Via Piero Gobetti 93/3 40129 Bologna, Italy
⁵ INFN, Sezione di Bologna Viale Berti Pichat 6/2 40127 Bologna, Italy
⁶ INAF – IRA Via Gobetti 101 I-40129 Bologna, Italy
⁷ Department of Physics, Informatics and Mathematics, University of Modena and Reggio Emilia 41125 Modena, Italy
⁸ IRAP, Université de Toulouse, CNRS, CNES, UT3-UPS Toulouse, France
⁹ Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM 91191 Gif-sur-Yvette, France
¹⁰ INAF – Osservatorio Astronomico di Brera Via E. Bianchi 46 I-23807 Merate (LC), Italy
¹¹ Leiden Observatory, Leiden University PO Box 9513 2300 RA Leiden, The Netherlands
¹² California Institute of Technology 1200 East California Boulevard Pasadena CA 91125, USA
¹³ Center for Astrophysics | Harvard & Smithsonian 60 Garden Street Cambridge MA 02138, USA
¹⁴ Curtin Institute for Data Science, Curtin University GPO Box U1987 Perth WA 6845, Australia

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Received: 27 June 2025
Accepted: 8 January 2026

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 (≲10²³ 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.