Dark matter substructure cannot explain properties of the Fermi Galactic Centre excess

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Title: Dark matter substructure cannot explain properties of the Fermi Galactic Centre excess
Authors: Clark, HA
Scott, P
Trotta, R
Lewis, GF
Item Type: Journal Article
Abstract: An excess of gamma rays has been identified at the centre of the Milky Way, and annihilation of dark matter has been posited as a potential source. This hypothesis faces significant challenges: difficulty characterizing astrophysical backgrounds, the need for a non-trivial adiabatic contraction of the inner part of the Milky Way's dark matter halo, and recent observations of photon clustering, which suggest that the majority of the excess is due to unresolved point sources. Here we point out that the apparent point-like nature of the emission rules out the dark matter interpretation of the excess entirely. Attempting to model the emission with dark matter point sources either worsens the problem with the inner slope, requires an unrealistically large minihalo fraction toward the Galactic Centre, or overproduces the observed emission at higher latitudes.
Issue Date: 26-Jul-2018
Date of Acceptance: 27-Jun-2018
ISSN: 1475-7516
Publisher: IOP Publishing
Journal / Book Title: Journal of Cosmology and Astroparticle Physics
Volume: 2018
Issue: 7
Copyright Statement: © 2018 IOP Publishing Ltd and Sissa Medialab. This is an author-created, un-copyedited version of an article accepted for publication in Journal of Cosmology and Astroparticle Physics. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The definitive publisher authenticated version is available online at
Sponsor/Funder: Science and Technology Facilities Council (STFC)
European Commission
Science and Technology Facilities Council
Science and Technology Facilities Council (STFC)
Funder's Grant Number: ST/K00414X/1
Keywords: Science & Technology
Physical Sciences
Astronomy & Astrophysics
Physics, Particles & Fields
dark matter theory
gamma ray experiments
particle physics - cosmology connection
0201 Astronomical And Space Sciences
0202 Atomic, Molecular, Nuclear, Particle And Plasma Physics
Nuclear & Particles Physics
Publication Status: Published
Article Number: 060
Online Publication Date: 2018-07-26
Appears in Collections:Physics
Faculty of Natural Sciences

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