Galactic dark matter search via phenomenological astrophysics modeling

Huang, Xiaoyuan; Ensslin, Torsten und Selig, Marco (2016): Galactic dark matter search via phenomenological astrophysics modeling. In: Journal of Cosmology and Astroparticle Physics, Nr. 4, 30

Abstract

Previous searches for the gamma-ray signatures of annihilating galactic dark matter used prede fined spatial templates to describe the background of gamma-ray emission from astrophysical processes like cosmic ray interactions. In this work, we aim to establish an alternative approach, in which the astrophysical components are identified solely by their spectral and morphological properties. To this end, we adopt the recent reconstruction of the diffuse gamma-ray sky from Fermi data by the (DPO)-P-3 algorithm and the fact that more than 90% of its flux can be represented by only two spectral components, resulting form the dense and dilute interstellar medium. Under these presumptions, we con firm the reported DM annihilationlike signal in the inner Galaxy and derive upper limits for dark matter annihilation cross sections. We investigate whether the DM signal could be a residual of the simplified modeling of astrophysical emission by inspecting the morphology of the regions, which favor a dark matter component. The central galactic region favors strongest for such a component with the expected spherically symmetric and radially declining pro fi le. However, astrophysical structures, in particular sky regions which seem to host most of the dilute interstellar medium, obviously would bene fi t from a DM annihilation-like component as well. Although these regions do not drive the fi t, they warn that a more detailed understanding of astrophysical gamma-ray emitting processes in the galactic center region are necessary before de finite claims about a DM annihilation signal can be made. The regions off the Galactic plane actually disfavor the best fi t DM annihilation cross section from the inner Galactic region unless the radial decline of the Galactic DM density pro fi le in the outer regions is significantly steeper than that usually assumed.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Physik
• Themengebiete: 500 Naturwissenschaften und Mathematik > 530 Physik
• ISSN: 1475-7516
• Sprache: Englisch