Qiang Yuan, Yixian Cao, Jie Liu, Pengfei Yin, Liang Gao, Xiao-Jun Bi, Xinmin Zhang
In this paper we study the properties of the $\gamma$-ray emission from annihilation of weakly interacting massive particle (WIMP) dark matter. Generally the WIMP serves as a candidate for the cold dark matter, however when produced non-thermally it could behave like a warm dark matter. Due to the large free-streaming length in the scenario of warm WIMP the substructure contend of dark matter halo will be significantly different from the cold WIMP counterpart, consequently the predicted $\gamma$-ray signal from dark matter halo will also be different. In this paper we use high resolution numerical simulations of a Milky-Way like halo to calculate the $\gamma$-ray signals from the warm WIMP annihilation, and compare with that from the cold WIMPs. Big differences from the subhalo skymap and statistical properties are shown. It was also found that the Galactic center might be better for the detection of warm WIMPs than subhalos, which might be different from the cold dark matter scenario. As a specific example we consider the non-thermally produced neutralino of supersymmetric model and discuss the detectability of warm WIMPs with Fermi $\gamma$-ray telescope.
View original:
http://arxiv.org/abs/1203.5636
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