Dark matter annihilation or unresolved astrophysical sources? Anisotropy probe of the origin of the cosmic gamma-ray background
Dark matter annihilation or unresolved astrophysical sources? Anisotropy probe of the origin of the cosmic gamma-ray background
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DOI：
10.1103/physrevd.75.063519
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发表时间：
2006-12
影响因子：
5
通讯作者：
S. Ando;E. Komatsu;Takuro Narumoto;T. Totani
中科院分区：
文献类型：
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作者：
S. Ando;E. Komatsu;Takuro Narumoto;T. Totani
宇宙伽马射线背景(CGB)的起源是高能天体物理学中一个长期存在的谜团。可能的候选者包括普通的天体物理物体，如未分辨的blazar，以及更奇异的过程，如暗物质湮灭。虽然很难单独从平均强度数据中区分它们，但可以使用各向异性数据来代替。我们研究了来自未分辨blazar和暗物质湮灭(包括来自暗物质亚结构的贡献)的CGB各向异性，我们发现来自这两个源的角功率谱是非常不同的。然后，我们通过将未分辨的blazar分量作为已知背景，使用各向异性数据来关注暗物质湮灭信号的可检测性。我们发现，在伽马射线大面积太空望远镜(GLAST)两年的全天观测中，只要暗物质湮灭对CGB在10GeV左右的>；~0.3有一定的贡献，暗物质的特征就应该可以在CGB的角功率谱中探测到。我们的结论是，用GLAST测量CGB的各向异性应该是揭示CGB起源的有力工具，并有可能成为首次探测暗物质湮灭的工具。
The origin of the cosmic gamma-ray background (CGB) is a longstanding mystery in high-energy astrophysics. Possible candidates include ordinary astrophysical objects such as unresolved blazars, as well as more exotic processes such as dark matter annihilation. While it would be difficult to distinguish them from the mean intensity data alone, one can use anisotropy data instead. We investigate the CGB anisotropy both from unresolved blazars and dark matter annihilation (including contributions from dark matter substructures), and we find that the angular power spectra from these sources are very different. We then focus on detectability of dark matter annihilation signals using the anisotropy data by treating the unresolved blazar component as a known background. We find that the dark matter signature should be detectable in the angular power spectrum of the CGB from two-year all-sky observations with the Gamma Ray Large Area Space Telescope (GLAST), as long as the dark matter annihilation contributes to a reasonable fraction, e.g., >~0.3, of the CGB at around 10 GeV. We conclude that the anisotropy measurement of the CGB with GLAST should be a powerful tool for revealing the CGB origin, and potentially for the first detection of dark matter annihilation.