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We present Higgs-Portal dark matter (DM) models to explain the reported Galactic Center GeV gamma-ray excess. Naive effective theories are inconsistent with direct detection constraint for the relevant parameter range. Simple extended…

High Energy Physics - Phenomenology · Physics 2015-04-28 P. Ko , Wan-Il Park , Yong Tang

Millisecond pulsars have been discussed as a possible source of the gamma-ray excess observed from the region surrounding the Galactic Center. With this in mind, we use the observed population of bright low-mass X-ray binaries to estimate…

High Energy Astrophysical Phenomena · Physics 2016-03-01 Ilias Cholis , Dan Hooper , Tim Linden

The Fermi Collaboration has recently updated their analysis of gamma rays from the center of the Galaxy. They reconfirm the presence of an unexplained emission feature which is most prominent in the region of $1-10$ GeV, known as the…

High Energy Physics - Phenomenology · Physics 2018-01-11 Abraham Achterberg , Melissa van Beekveld , Sascha Caron , Germán A. Gómez-Vargas , Luc Hendriks , Roberto Ruiz de Austri

The excess above 1 GeV in the energy spectrum of the diffuse Galactic gamma radiation, measured with the EGRET experiment, can be interpreted as the annihilation of Dark Matter (DM) particles. The DM is distributed in a halo around the…

Astrophysics · Physics 2007-10-29 Markus Weber

There is growing evidence that the Galactic Center Excess identified in the $\textit{Fermi}$-LAT gamma-ray data arises from a population of faint astrophysical sources. We provide compelling supporting evidence by showing that the…

High Energy Astrophysical Phenomena · Physics 2019-09-23 Oscar Macias , Shunsaku Horiuchi , Manoj Kaplinghat , Chris Gordon , Roland M. Crocker , David M. Nataf

We explore the non-commutative space-time to revive the idea that gamma-ray excess in the galactic center can be the result of particle dark matter annihilation. In the non-commutative theory, the photon spectrum is produced by direct…

High Energy Physics - Phenomenology · Physics 2020-07-06 Zahra Rezaei , S. Peyman Zakeri

Fifteen years of the Fermi Large Area Telescope (LAT) data in the halo region of the Milky Way (MW) are analyzed to search for gamma rays from dark matter annihilation. Gamma-ray maps within the region of interest ($|l| \le 60^\circ$,…

High Energy Astrophysical Phenomena · Physics 2025-11-25 Tomonori Totani

The apparent gamma-ray excess in the Galactic center region and inner Galaxy has attracted considerable interest, notably because both its spectrum and radial distribution are consistent with an interpretation in terms of annihilating dark…

High Energy Astrophysical Phenomena · Physics 2014-12-03 Torsten Bringmann , Martin Vollmann , Christoph Weniger

Several classes of astrophysical sources contribute to the approximately isotropic gamma-ray background measured by the Fermi Gamma-Ray Space Telescope. In this paper, we use Fermi's catalog of gamma-ray sources (along with corresponding…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Ilias Cholis , Dan Hooper , Samuel D. McDermott

Many models currently exist which attempt to interpret the excess of gamma rays emanating from the Galactic Center in terms of annihilating or decaying dark matter. These models typically exhibit a variety of complicated cascade mechanisms…

High Energy Physics - Phenomenology · Physics 2017-04-11 Kimberly K. Boddy , Keith R. Dienes , Doojin Kim , Jason Kumar , Jong-Chul Park , Brooks Thomas

We study the annihilating dark matter contribution to the extra-galactic diffuse gamma-ray background spectrum, motivated by the recent observations of cosmic-ray positron/electron anomalies. The observed diffuse gamma-ray flux provides…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-02 Masahiro Kawasaki , Kazunori Kohri , Kazunori Nakayama

We use recently released data on the positron-to-electron ratio in cosmic rays from the AMS-02 experiment to constrain dark matter annihilation in the Milky Way. Due to the yet unexplained positron excess, limits are generally weaker than…

High Energy Physics - Phenomenology · Physics 2013-10-31 Joachim Kopp

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,…

High Energy Astrophysical Phenomena · Physics 2024-08-22 Ilias Cholis , Iason Krommydas

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

Dark matter annihilation in Galactic substructure produces diffuse gamma-ray emission of remarkably constant intensity across the sky, and in general this signal dominates over the smooth halo signal at angles greater than a few tens of…

High Energy Astrophysical Phenomena · Physics 2009-07-02 Jennifer M. Siegal-Gaskins

Based on three years of Fermi Large Area Telescope (LAT) gamma-ray data of the Virgo cluster, evidence for an extended emission associated with dark matter pair annihilation in the b b-bar channel has been reported by Han et al. [1]. After…

High Energy Astrophysical Phenomena · Physics 2013-05-30 Oscar Macías-Ramírez , Chris Gordon , Anthony M. Brown , Jenni Adams

Recently, a preliminary spectrum from the Fermi Gamma-ray Space Telescope has been presented for the inner galaxy (-30 < l < 30, -5 < b < 5), as well as the galactic center (-1 < l < 1, -1< b < 1). We consider the implications of these data…

High Energy Astrophysical Phenomena · Physics 2009-07-29 Ilias Cholis , Gregory Dobler , Douglas P. Finkbeiner , Lisa Goodenough , Tracy R. Slatyer , Neal Weiner

The "GeV-excess" of the diffuse gamma-rays in the halo is studied with a template fit based on energy spectra for each possible process of gamma-ray emission. Such a fit allows to determine the background and signal simultaneously, so the…

High Energy Astrophysical Phenomena · Physics 2016-10-28 Wim de Boer , Iris Gebauer , Alexander Neumann , Peter L. Biermann

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

We make a detailed analysis of the indirect diffuse gamma-ray signals from dark matter annihilation in the Galaxy. We include the prompt emission, as well as the emission from inverse Compton scattering whenever the annihilation products…

High Energy Astrophysical Phenomena · Physics 2012-11-14 Steve Blanchet , Julien Lavalle