Non-thermal emission from galaxy clusters: feasibility study with SKA1

TL;DR

This study assesses SKA1's capability to detect and analyze non-thermal radio emissions in galaxy clusters, focusing on faint diffuse sources and comparing advanced deconvolution algorithms.

Contribution

It introduces a feasibility framework for SKA1 observations of galaxy clusters, including simulations and testing a novel sparse representation deconvolution method.

Findings

SKA1 can effectively detect diffuse radio sources in galaxy clusters.

The new deconvolution algorithm outperforms classical CLEAN in faint source detection.

Simulations demonstrate SKA1's potential for studying non-thermal phenomena in clusters.

Abstract

Galaxy clusters are known to host a variety of extended radio sources: tailed radio galaxies whose shape is modelled by the interaction with the intra-cluster medium (ICM); radio bubbles filling cavities in the ICM distribution and rising buoyantly through the thermal gas; diffuse giant radio sources ("halos" and "relics") revealing the presence of relativistic electrons and magnetic fields in the intra-cluster volume. It is currently the subject of an active debate how the non-thermal components that we observe at radio wavelengths affect the physical properties of the ICM and depend on the dynamical state of galaxy clusters. In this work we start our SKA1 feasibility study of the "radio cluster zoo" through simulations of a typical radio-loud cluster, hosting several bright tailed radio galaxies and a diffuse radio halo. Realistic simulations of SKA1 observations are obtained through the MeqTrees software. A new deconvolution algorithm, based on sparse representations and optimised for the detection of faint diffuse astronomical sources, is tested and compared to the classical CLEAN method.