标题： 仔细研究各向同性伽马射线背景以寻找暗物质 显示英文标题

标题： Scrutinizing the Isotropic Gamma-Ray Background in Search of Dark Matter

摘要： 各向同性伽马射线背景（IGRB），由费米大面积望远镜测量，是多种星系外天体物理源的结果。这些源包括耀变体、恒星形成星系和射电星系。此外，超高能宇宙射线与红外背景的相互作用也对各向同性背景有贡献。利用费米伽马射线源目录中的信息以及针对这些源类的专门研究结果，从红外和射电观测中得出的数据，我们对其贡献于IGRB进行建模。除了传统的天体物理源外，暗物质可能是IGRB的一个组成部分。我们将传统天体物理源的模型和遥远星系中暗物质湮灭的模型结合起来，在考虑相关不确定性的情况下，从测量的IGRB推导出暗物质湮灭截面的限制。在计算暗物质的贡献时，我们包括了星系外晕及其子结构的流量，以及银河系晕在高银纬处的次级贡献。所得的限制与来自矮椭球星系的最强当前限制相当。在某些暗物质假设下，我们也发现各向同性背景中存在一个小的过量流量。我们的结果与朝向银河系中心的GeV能量范围内的伽马射线过量一致。 显示英文摘要

摘要： The isotropic gamma-ray background (IGRB), measured by the Fermi Large Area Telescope, is the result of several classes of extragalactic astrophysical sources. Those sources include blazars, start-forming galaxies and radio galaxies. Also, ultra-high-energy cosmic rays interacting with the infrared background, contribute to the isotropic background. Using information from Fermi's gamma-ray sources catalog and the results of dedicated studies of these classes of sources, from observations at the infrared and radio, we model their contribution to the IGRB. In addition to conventional astrophysical sources, dark matter may be a component of the IGRB. We combine our model of conventional astrophysical sources and of dark matter annihilation in distant galaxies, marginalizing over relevant uncertainties, to derive constraints on the dark matter annihilation cross section, from the measured IGRB. In calculating the contribution from dark matter we include the flux from extragalactic halos and their substructure and also the subdominant contribution from Milky Way's halo at high galactic latitudes. The resulting constraints are competitive with the strongest current constraints from the dwarf spheroidal galaxies. Under certain dark matter assumptions, we also find an indication for a small excess flux in the isotropic background. Our results are consistent with the gamma-ray excess at GeV energies toward the galactic center.