Complex diffuse emission in the $z=0.52$ cluster PLCK~G004.5-19.5

TL;DR

This study reports on radio observations of galaxy cluster PLCK G004.5-19.5 at redshift 0.52, revealing unusual diffuse emission structures and linking them to cluster disturbance, contributing to understanding high-redshift merger-related particle acceleration.

Contribution

First detailed radio analysis of PLCK G004.5-19.5 at high redshift, identifying diffuse emission features and their association with cluster disturbance.

Findings

Detection of diffuse radio emission resembling relics and halos

Cluster shows disturbed X-ray morphology

Adds valuable data on high-redshift radio relics and halos

Abstract

We present radio observations of the galaxy cluster PLCK G004.5-19.5 ($z=0.52$) using the Giant Metrewave Radio Telescope at 150~MHz, 325~MHz, and 610~MHz. We find an unusual arrangement of diffuse radio emission in the center and periphery of the cluster, as well as several radio galaxies with head-tail emission. A patch of peripheral emission resembles a radio relic, and central emission resembles a radio halo. Reanalysis of archival XMM-Newton X-ray data shows that PLCK G004.5-19.5 is disturbed, which has a known correlation with the existence of radio relics and halos. Given that the number of known radio halos and radio relics at $z>0.5$ is very limited, PLCK G004.5-19.5 is an important addition to understanding merger-related particle acceleration at higher redshifts.