The role of Dark Matter annihilation in the radio emission of the galaxy cluster A520. (arXiv:1812.01445v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Marchegiani_P/0/1/0/all/0/1">P. Marchegiani</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Colafrancesco_S/0/1/0/all/0/1">S. Colafrancesco</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Khanye_N/0/1/0/all/0/1">N.F. Khanye</a>
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 $b bar b$ for a magnetic field
of 5 $mu$G.
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 $b bar b$ for a magnetic field
of 5 $mu$G.
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