A hidden radio halo in A1682?

TL;DR

This paper reports the detection of a potential hidden radio halo in galaxy cluster A1682 using low-frequency GMRT observations, revealing diffuse emission superposed on complex radio galaxy structures.

Contribution

First detection of a low surface brightness radio halo in A1682 at frequencies below 330 MHz, highlighting challenges in imaging due to bright radio galaxies.

Findings

Extended low surface brightness emission in A1682

Superposition of radio galaxies and diffuse emission

Detection at multiple low frequencies

Abstract

High sensitivity observations of radio halos in galaxy clusters at frequencies lower than 330 MHz are still relatively rare, and very little is known compared to the classical 1.4 GHz images. The few radio halos imaged down to 150-240 MHz show a considerable spread in size, morphology and spectral properties. All clusters belonging to the GMRT Radio Halo Survey with detected or candidate cluster-scale diffuse emission have been imaged at 325 MHz with the GMRT. Few of them were also observed with the GMRT at 240 MHz and 150 MHz. For A1682, imaging is particularly challenging due to the presence of strong and extended radio galaxies at the center. Our data analysis suggests that the radio galaxies are superposed to very low surface brightness radio emission extended on the cluster scale, which we present here.