http://arxiv.org/abs/1312.7609
Gamma-ray is a good probe of dark matter particles in the Universe. Using 4.5 year Fermi-LAT observation of the Andromeda (M31) galaxy, we constrain the dark matter annihilation model parameters. The typical annihilation final states $b\bar{b}$, $W^{+}W^{-}$, $\mu^{+}\mu^{-}$ and $\tau^{+}\tau^{-}$ are investigated. We pay special attention to the discussion of the dark matter distribution as well as the substructures in M31 in this work. Considering the contribution of substructures to the dark matter annihilation, the constraints on the cross section are comparable to other probes such as the dwarf spheroidal galaxies. We also discuss the inverse Compton scattering component from the electrons/positrons, and find that it can significantly improve the constraints in the high mass region of dark matter particles.
Tue, 31 Dec 13
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