A KAT-7 view of a low-mass sample of galaxy clusters

Abstract

Radio observations over the last two decades have provided evidence that diffuse synchrotron emission in the form of megaparsec-scale radio halos in galaxy clusters is likely tracing regions of the intracluster medium where relativistic particles are accelerated during cluster mergers. In this paper we present results of a survey of 14 galaxy clusters carried out with the 7-element Karoo Array Telescope at 1.86 GHz, aimed to extend the current studies of radio halo occurrence to systems with lower masses (M${}_{500}>4\times 10^{14}$ M${}_{\odot }$). We found upper limits at the $0.6-1.9\times 10^{24}$ Watt Hz${}^{-1}$ level for $\sim 50\%$ of the sample, confirming that bright radio halos in less massive galaxy clusters are statistically rare.

arXiv comment7 pages, 4 figures. Conference proceeding of "The many facets of extragalactic radio surveys: towards new scientific challenges", 20-23 October 2105, Bologna, Italy