Search for γ-ray emission from dark matter particle interactions from Andromeda and Triangulum Galaxies with the Fermi Large Area Telescope

作     者：Mauro, Mattia Di Hou, Xian Eckner, Christopher Zaharijas, Gabrijela Charles, Eric 

作者机构：NASA Goddard Space Flight Center GreenbeltMD20771 United States Catholic University of America Department of Physics WashingtonDC20064 United States Yunnan Observatories Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming650216 China Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100012 China Center for Astrophysics and Cosmology University of Nova Gorica Vipavska 13 Nova GoricaSI-5000 Slovenia SLAC National Accelerator Laboratory Stanford University StanfordCA94305 United States 

出 版 物：《arXiv》 (arXiv)

年 卷 期：2019年

核心收录：

主　　题：Galaxies 

摘      要：The Andromeda (M31) and Triangulum (M33) galaxies are the closest Local Group galaxies to the Milky Way, being only 785 and 870 kpc away. These two galaxies provide an independent view of high-energy processes that are often obscured in our own Galaxy, including possible signals of dark matter (DM) particle interactions. The Fermi Large Area Telescope (Fermi-LAT) preliminary eight year list of sources includes both M31, which is detected as extended with a size of about 0.4◦, and M33, which is detected as a point-like source. The spatial morphology of M31 γ-ray emission could trace a population of unresolved sources and energetic particles originating in sources not related to massive star formation. Alternatively, the γ-ray emission could also be an indication of annihilation or decay of DM particles. We investigate these two possibilities using almost 10 years of data from the Fermi LAT. An interpretation that involves only a DM γ-ray emission is in tension with the current limits from other searches, such as those targeting Milky Way dwarf spheroidal galaxies. When we include a template of astrophysical emission, tuned on γ-ray data or from observations of these galaxies in other wavelengths, we do not find any significant evidence for a DM contribution and we set limits for the annihilation cross section that probe the thermal cross section for DM masses up to a few tens of GeV in the b¯b and τ+τ− channels. For models where the DM substructures have masses above 10−6 solar masses our limits probe the DM interpretation of the Fermi LAT Galactic center excess. We provide also the lower limit for the DM decay time assuming the same spatial models of the DM distribution in M31 and M33. Copyright © 2019, The Authors. All rights reserved.