Non-Thermal Radio Emission From Dark Matter Annihilation Processes in Simulated Coma Like Galaxy Clusters

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Addis Ababa University


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.



Non-Thermal Radio, Emission, Annihilation Processes