Detection of diffuse radio emission at large distance from the center of the galaxy cluster A2255

TL;DR

This paper reports deep low-frequency radio observations of galaxy cluster A2255, revealing extended diffuse emission and new structures far from the center, supporting theories of large-scale structure formation shocks.

Contribution

It presents the first detection of large-scale diffuse radio emission at 85 cm in A2255, including new structures 2 Mpc from the cluster center, linked to LSS formation shocks.

Findings

Extended radio halo and relic structures detected

Two new diffuse structures found 2 Mpc from the center

Supports connection between radio emission and large-scale shocks

Abstract

Low-frequency radio observations of galaxy clusters are the key to detecting the diffuse extended emission associated with them. The presence and properties of such radio sources in galaxy clusters reveal the existence of magnetic fields on a large scale and allow theories to be tested concerning both the origin of relativistic particles in the ICM and their propagation. A deep radio bservation of the A2255 galaxy cluster was carried out at 85 cm with the WSRT. The good UV-coverage and sensitivity achieved by these observations allowed us to image the complex structure of the low-brightness, extended cluster sources (radio halo and relic). These sources show a larger extent than what has been imaged so far at this frequency, with two new structures located SW and NW of the cluster center and at projected distances of 2 Mpc from it. The physical properties of the newly detected structures, together with the active dynamical state of the cluster, support a connection with large-scale structure (LSS) formation shocks.