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If the dark matter is unstable, the decay of these particles throughout the universe and in the halo of the Milky Way could contribute significantly to the isotropic gamma-ray background (IGRB) as measured by Fermi. In this article, we…

High Energy Astrophysical Phenomena · Physics 2019-03-20 Carlos Blanco , Dan Hooper

Gamma-ray lines from dark matter annihilation ($\chi\chi\to \gamma X$, where $X=\gamma,h,Z$) are always accompanied, at lower energies, by a continuum gamma-ray spectrum stemming both from radiative corrections ($X=\gamma$) and from the…

High Energy Astrophysical Phenomena · Physics 2016-08-03 Stefano Profumo , Farinaldo S. Queiroz , Carlos E. Yaguna

Dark matter annihilation into charged particles is necessarily accompanied by gamma rays, produced via radiative corrections. Internal bremsstrahlung from the final state particles can produce hard gamma rays up to the dark matter mass,…

Astrophysics · Physics 2010-02-01 Nicole F. Bell , Thomas D. Jacques

Cosmic rays accelerated to ultra-high energies (E>4x10^19 eV) in electric fields in accretion discs around supermassive black holes are discussed. Particle injection spectra are assumed to be harder than those formed in acceleration on…

High Energy Astrophysical Phenomena · Physics 2020-01-08 A. Uryson

We incorporate Milky Way dark matter halo profile uncertainties, as well as an accounting of diffuse gamma-ray emission uncertainties in dark matter annihilation models for the Galactic Center Extended gamma-ray excess (GCE) detected by the…

High Energy Physics - Phenomenology · Physics 2016-04-20 Kevork N. Abazajian , Ryan E. Keeley

We analyze new diffuse gamma-ray data from the Fermi Gamma-ray Space Telescope, which do not confirm an excess in the EGRET data at galactic mid-latitudes, in combination with measurements of electron and positron fuxes from PAMELA, Fermi…

High Energy Physics - Phenomenology · Physics 2009-06-30 V. Barger , Y. Gao , W. -Y. Keung , D. Marfatia , G. Shaughnessy

We study the gamma rays observed by the Fermi Gamma Ray Space Telescope from the direction of the Galactic Center and find that their angular distribution and energy spectrum are well described by a dark matter annihilation scenario. In…

High Energy Physics - Phenomenology · Physics 2009-11-11 Lisa Goodenough , Dan Hooper

Positron and electron cosmic rays provide a complementary way to study the galactic environment. The actual cosmic rays experiments, for instance PAMELA and HEAT, have presented very exciting results in this field. The observed positron…

Astrophysics · Physics 2009-02-04 Roberto A. Lineros

The detection of non-baryonic dark matter through its gamma-ray annihilation in the centre of our galaxy has been studied. The gamma fluxes according to different models have been simulated and compared to those expected to be observed with…

If dark matter decays or annihilates into electrons and positrons, it can affect radiation and cosmic-ray backgrounds. We review a novel, more general analysis of constraints on decaying dark matter models, by introducing the response…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-13 Le Zhang

The presence of an excess gamma-ray signal toward the Galactic center (GC) has now been well established, and is known as the GC excess. Leading explanations for the signal include mis-modeling of the Galactic diffuse emission along the…

High Energy Astrophysical Phenomena · Physics 2021-03-24 Anne-Katherine Burns , Max Fieg , Christopher M. Karwin , Arvind Rajaraman

Recently, a spatially extended excess of gamma rays collected by the Fermi-LAT from the inner region of the Milky Way has been detected by different groups and with increasingly sophisticated techniques. Yet, any final conclusion about the…

High Energy Astrophysical Phenomena · Physics 2015-02-11 Francesca Calore , Ilias Cholis , Christoph Weniger

The origin of the cosmic gamma-ray background at 1-20 MeV remains a mystery. We show that gamma-ray emission accompanying annihilation of 20 MeV dark matter particles explains most of the observed signal. Our model satisfies all of the…

Astrophysics · Physics 2009-11-13 Kyungjin Ahn , Eiichiro Komatsu

Measurements of the cosmic ray antiproton spectrum can be used to search for contributions from annihilating dark matter and to constrain the dark matter annihilation cross section. Depending on the assumptions made regarding cosmic ray…

High Energy Astrophysical Phenomena · Physics 2015-03-19 Dan Hooper , Tim Linden , Philipp Mertsch

I discuss contributions to the diffuse gamma-ray background from decay and annihilation of weakly interacting massive particles (WIMPs). I first review the calculation of the cosmological abundance of a WIMP and show that it is simply…

Astrophysics · Physics 2007-05-23 Marc Kamionkowski

The all-sky survey in high-energy gamma rays (E > 30 MeV) carried out by the Energetic Gamma Ray Experiment Telescope (EGRET) aboard the Compton Gamma-Ray Observatory provides a unique opportunity to examine in detail the diffuse gamma-ray…

Astrophysics · Physics 2011-04-15 Yu. A. Golubkov , M. Yu. Khlopov

Very high energy (VHE) gamma-rays from extragalactic sources, interacting by gamma-gamma collisions with diffuse intergalactic radiation fields, provide an alternative way to constrain the diffuse background light, completely independent of…

High Energy Astrophysical Phenomena · Physics 2015-06-04 Luigi Costamante

We explore the possibility that the diffuse gamma-ray background radiation (GBR) at high galactic latitudes could be dominated by inverse Compton scattering of cosmic ray (CR) electrons on the cosmic microwave background radiation and on…

Astrophysics · Physics 2009-10-31 Arnon Dar , A. De Rújula

High energy electrons and positrons from annihilating dark matter can imprint unique angular anisotropies on the diffuse gamma-ray flux by inverse Compton scattering off the interstellar radiation field. We develop a numerical tool to…

High Energy Astrophysical Phenomena · Physics 2011-02-10 Le Zhang , Francesco Miniati , Guenter Sigl

Gamma rays and microwave observations of the Galactic Center and surrounding areas indicate the presence of anomalous emission, whose origin remains ambiguous. The possibility of dark matter (DM) annihilation explaining both signals through…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-28 Andrey E. Egorov , Jennifer M. Gaskins , Elena Pierpaoli , Davide Pietrobon