A520 is a hot and luminous galaxy cluster, where gravitational lensing and X-ray measures reveal a different spatial distribution of baryonic and Dark Matter. This cluster hosts a radio halo, whose map shows a separation between the North-East and the South-West part of the cluster, similarly to what is observed in gravitational lensing maps. In this paper we study the possibility that the diffuse radio emission in this cluster is produced by Dark Matter annihilation. We find that in the whole cluster the radio emission should be dominated by baryonic phenomena; if a contribution from Dark Matter is present, it should be searched in a region in the NE part of the cluster, where a peak of the radio emission is located close to a Dark Matter sub-halo, in a region where the X-ray emission is not very strong. By estimating the radio spectrum integrated in this region using data from publicly available surveys, we find that this spectrum can be reproduced by a Dark Matter model for a neutralino with mass 43 GeV and annihilation final state bb for a magnetic field of 5 µG.
Dark Matter annihilation is a possible source of relativistic electrons in galaxy clusters; these electrons, interacting with intra-cluster magnetic fields, can contribute to the diffuse radio emission observed in several clusters. We explore the possibility that Dark Matter annihilation can be at the origin of the radio emission in the cluster A520. We find that, if a radio emission of Dark Matter origin is present in this cluster, it can be observed in a region in the NE part of the cluster, whereas we expect that in most parts of the cluster the emission from ordinary matter should be dominant. High-energy measurements in X-rays and gamma rays don't appear to be suitable to discriminate between ordinary and Dark Matter origin for the models we have considered, because the corresponding non-thermal emissions predicted in this cluster are well below the sensitivity of present and forthcoming instruments.
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