Dark Matter Searches with Clusters of Galaxies

Abstract Dark matter may annihilate or decay to produce Standard Model particles including gamma-rays but also energetic electrons and positrons. These high energy particles diffuse, loose energy and produce a broad spectrum of secondary radiation including radio synchrotron emission in the presence of magnetic fields and the inverse Compton scattering of CMB photons and star light to X-ray and gamma-ray energies. Clusters of galaxies are prime targets for multiwavelength dark matter searches as they both host large dark matter densities and effective trap high-energy particles long enough for them to radiate. Clusters are also among the strongest probes of dark matter decay. We will review the utility of clusters for dark matter searches and current constraints. In particular, we will show that current radio observations of clusters are competitive with gamma-ray, and future facilities like LOFAR and ASKAP are expected to give large gains for dark matter searches.