Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Phys Rev Lett. 2018 Mar 9;120(10):101101. doi: 10.1103/PhysRevLett.120.101101.
We use 413 weeks of publicly available Fermi Pass 8 gamma-ray data combined with recently developed galaxy group catalogs to search for evidence of dark matter annihilation in extragalactic halos. In our study, we use luminosity-based mass estimates and mass-to-concentration relations to infer the J factors and associated uncertainties for hundreds of galaxy groups within a redshift range z≲0.03. We employ a conservative substructure boost factor model, which only enhances the sensitivity by an O(1) factor. No significant evidence for dark matter annihilation is found, and we exclude thermal relic cross sections for dark matter masses below ∼30 GeV to 95% confidence in the bb[over ¯] annihilation channel. These bounds are comparable to those from Milky Way dwarf spheroidal satellite galaxies. The results of our analysis increase the tension but do not rule out the dark matter interpretation of the Galactic Center excess. We provide a catalog of the galaxy groups used in this study and their inferred properties, which can be broadly applied to searches for extragalactic dark matter.
我们利用 413 周公开的费米卫星 Pass 8 伽马射线数据，结合最近开发的星系团目录，来搜索暗物质在河外晕中的湮灭证据。在我们的研究中，我们使用基于光度的质量估计和质量与集中比关系，来推断在红移范围 z≲0.03 内的数百个星系团的 J 因子和相关不确定性。我们采用了一种保守的亚结构增强因子模型，该模型仅将灵敏度提高了 O(1)倍。我们没有发现暗物质湮灭的显著证据，并排除了暗物质质量低于 ∼30GeV 的热 relic 横截面，置信度为 95%，在 bb[over ¯]湮灭通道中。这些约束与来自银河系矮椭球星系卫星星系的约束相当。我们分析的结果增加了紧张局势，但并没有排除对银河系中心过剩的暗物质解释。我们提供了本研究中使用的星系团目录及其推断的性质，这些性质可以广泛应用于河外暗物质的搜索。
