Gamma-ray Emission From Dark Matter Annihilation Process In Simulated Coma Like Galaxy Cluster
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Date
2018-09-03
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Addis Ababa University
Abstract
Galaxy clusters are good targets to search for signals from dark matter (DM)
annihilation process as they are dominatly composed of DM. From DM annihilation
process neutral and charged pions are beleived to be produced. The neutral pions
decay directly into gamma-rays, while the secondary particle e_ produced from the
charged pions are expected to emit gamma-rays through inverse compton scattering
(ICS) and non-thermal bremsstrahlung processes. Taking energetic particles that
are e_ produced from DM annihilation process for the model of the origin of the
extended secondary particle observed in radio halos, the corresponding gamma-ray
emission in those regions, we have studied both their morphology and the spectral
energy distribution using simulated Coma like galaxy clusters. Using raw galaxy
cluster data from large set of MUltiDark SImulation of galaxy Clusters (MUSIC-
2) dataset simulation we choose three galaxy clusters for calculating gamma-ray
emmission from DM annhilation process. For our calculation we have considered
a neutralino annihilation of bb species and mass of DM model of neutralino mass
of 35 GeV with annihilation cross-section times velocity of <_v> = 1_ 1026 cm3
s1. Among the three simulated galaxy clusters, simulated galaxy cluster SGC282
showes the densest DM distribution almost in all the regions of the map. The
differential gamma-ray flux obtained from neutral pion decay process is on average
an order of magnitude higher than that from non-thermal Bremsstrahlung process,
for similar photon energy, for all the three simulated galaxy clusters. For all the
three gamma-ray emission mechanisims from DM annihilation process, simulated
galaxy cluster SGC282 showes dominant differential gamma-ray flux densities.
Overall we have observed that the gamma-ray emission flux calculated in these
simulated galaxy cluster from the DM annihilation process is higher from regions
of denser DM halos in the simulated Coma like galaxy cluster as expected.
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Keywords
Dark Matter, Non-thermal Process in Galaxy Cluster, Virial Theorem