A low-frequency radio halo survey of the South Pole Telescope SZ-selected clusters with the GMRT

Abstract

ABSTRACT The presence of non-thermal electrons and large-scale magnetic fields in the intracluster medium is known through the detection of megaparsec (Mpc) scale diffuse radio synchrotron emission. Although a significant amount of progress in finding new diffuse radio sources has happened in the last decade, most of the investigation has been constrained towards massive low-redshift clusters. In this work, we explore clusters with redshift z > 0.3 in search of diffuse radio emission, at 325 MHz with the Giant Metrewave Radio Telescope. This campaign has resulted in the discovery of two new radio haloes (SPT-CL J0013−4906 and SPT-CL J0304−4401) along with two other detections (SPT-CL J2031−4037 and SPT-CL J2248−4431), previously reported (at 325 MHz) in the literature. In addition, we detect a halo candidate in one cluster in our sample, and upper limits for haloes are placed in eight clusters where no diffuse emission is detected. In the P1.4–LX plane, the detected haloes follow the observed correlation, whereas the upper limits lie above the correlation line, indicating the possibility of future detection with sensitive observations.