Non-Thermal Radio Emission From Dark Matter Annihilation Processes in Simulated Coma Like Galaxy Clusters
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Date
2018-07-04
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Addis Ababa University
Abstract
Taking secondary particles produced from dark matter annihilation process to the
origin of the extended diffuse radio emissions observed in galaxy clusters, we studied
both their morphology and radio spectral profile using simulated Coma like galaxy
clusters. We have considered a neutralino annihilation channel dominated by bb
species with a branching ratio of 1 and neutralino mass of 35 GeV with annihilation
cross-section times velocity value of 1_10��26 cm3 s��1. The radio emission maps
produced for the two simulated galaxy clusters which are based on the MUsic
SImulation of galaxy Clusters (MUSIC)-dataset reveal the observed radio halo
morphology showing radio emissions both from the central regions of the cluster
and substructures lying off-center. The flux density curve is in a good agreement
for _ _ 2 GHz with the obsevational values of (Thierbach et al., 2003) for the Coma
cluster of galaxies showing a small deviation at higher frequencies. The small
spectral index fluctuations observed in the wide cluster regions corresponds to the
DM substructures scattered with in the clusters. The spectral index values _ (-0.8,
-1.0) and _ (-1.6, -2.2) obtained in the very center and dark matter substructure
(cluster periphery) are in a good agreement with the work of (Giovannini et al.,
1993). The central spectral flattening and the peripheral steepening explain the
dense central and underdense peripheral DM regions, respectively.
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Keywords
Non-Thermal Radio, Emission, Annihilation Processes