Complex diffuse emission in the z = 0.52 cluster PLCK G004.5-19.5^⋆

¹ Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
e-mail: albert@strw.leidenuniv.nl
² European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany
³ SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands
⁴ INAF – Istituto di Radioastronomia, via P. Gobetti 101, 40129 Bologna, Italy
⁵ Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544, USA

Received: 25 January 2017
Accepted: 3 July 2017

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.