A combined LOFAR and XMM-Newton analysis of the disturbed cluster PSZ2G113.91-37.01

TL;DR

This study combines LOFAR and XMM-Newton data to analyze the complex radio and X-ray features of the merging galaxy cluster PSZ2G113.91-37.01, revealing insights into shock fronts, particle re-acceleration, and emission correlations.

Contribution

It provides a detailed multi-wavelength analysis of a merging cluster, identifying a cold front, re-acceleration in the relic, and correlations between radio and X-ray emissions, advancing understanding of cluster merger physics.

Findings

Detection of a cold front associated with the merger.

Evidence of particle re-acceleration in the northern relic.

Strong correlation between radio emission and X-ray residuals.

Abstract

In this work, we investigated the interplay between the X-ray and radio emission of the cluster PSZ2G113.91-37.01 (z = 0.371) using the high-quality XMM-Newton observations of the CHEX-MATE project, and the images of the LoTSS-DR2. The cluster is undergoing a merger along the north-south axis, and shows a central radio halo and two radio relics, one in the southern and one in the northern regions. The analysis of the intracluster medium distribution revealed the presence of a northern surface brightness jump associated to the merger event. By extracting spectra across this discontinuity, we classified the edge as a cold front. Furthermore, we made use of upgraded Giant Metrewave Radio Telescope observations that allowed us to perform a spectral analysis of the G113 radio emission. We found evidence of re-acceleration of particles in the northern relic, and we measured an associated Mach number of M = 1.95 $\pm$ 0.01, as inferred from radio observations. We then performed a point-to-point analysis of the X-ray and radio emission both in the halo and in the northern relic regions. We found a strong correlation for the halo and an anti-correlation for the relic. The former behaviour is in agreement with previous studies. The relic anti-correlation is likely related to the reverse radial distribution of the X-ray (increasing towards the cluster centre) and radio (decreasing towards the cluster centre) emissions. Finally, we performed a point-to-point analysis of the radio emission and the residuals obtained by subtracting a double beta model to the X-ray emission. We found a strong correlation between the two quantities. This behaviour suggests the presence of a connection between the process responsible for the radio emission and the one that leaves fluctuations in the X-ray observations.