Discovery of diffuse emission in the galaxy cluster A1689

TL;DR

This paper reports the discovery of a small radio halo in galaxy cluster A1689, identified through analysis of archival VLA radio observations, revealing diffuse synchrotron emission indicative of intracluster medium activity.

Contribution

First detection of a diffuse radio halo in A1689 using archival VLA data, expanding knowledge of radio emission in galaxy clusters.

Findings

Detected extended diffuse radio emission in A1689

Measured the halo's largest linear size as 730 kpc

Classified the emission as a small radio halo

Abstract

The aim of this work is to investigate the possible presence of extended diffuse synchrotron radio emission associated with the intracluster medium of the complex galaxy cluster A1689. The radio continuum emission of A1689 has been investigated by analyzing archival observations at 1.2 and 1.4 GHz obtained with the Very Large Array in different configurations. We report the detection of an extended, diffuse, low-surface brightness radio emission located in the central region of A1689. The surface brightness profile of the diffuse emission at 1.2 GHz indicates a central radio brightness of ~1.7 \mu Jy/arcsec^2 and the 3\sigma radio isophothes reveal the largest linear size to be 730 kpc. Given its central location, the low-level surface brightness, and the comparatively large extension, we classify the diffuse cluster-wide emission in A1689 as a small radio halo.