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Evidence of excess GeV emission nearly coinciding with the Galactic Centre has been interpreted as a possible signature of annihilating dark matter. In this paper, we argue that it seems too early to discard pulsars as a viable explanation…

High Energy Astrophysical Phenomena · Physics 2015-06-17 N. Mirabal

A cluster of galaxies is a huge system bounded by gravitation, and cosmic rays are thought to be confined in the system, thus it should contain much non-thermal components. Many theories predict significant gamma-ray emission that could be…

High Energy Astrophysical Phenomena · Physics 2009-12-18 Masaki Mori

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

The diffuse Fe XXV (6.7 keV) line emission observed in the Galactic ridge is widely accepted to be produced by a superposition of a large number of unresolved X-ray point sources. In the very central degrees of our Galaxy, however, the…

We study the variation of the spectrum of the Fermi Bubbles with Galactic latitude. Far from the Galactic plane (|b| > 30 degrees), the observed gamma-ray emission is nearly invariant with latitude, and is consistent with arising from…

High Energy Astrophysical Phenomena · Physics 2013-02-28 Dan Hooper , Tracy R. Slatyer

The discovery of the Fermi bubbles---a huge bilobular structure seen in GeV gamma-rays above and below the Galactic center---implies the presence of a large reservoir of high energy particles at $\sim 10 \, \text{kpc}$ from the disk. The…

High Energy Astrophysical Phenomena · Physics 2019-02-27 Philipp Mertsch , Vahé Petrosian

Excess of gamma rays with a spherical morphology around the Galactic center (GC) observed in the Fermi large area telescope (LAT) data is one of the most intriguing features in the gamma-ray sky. The excess has been interpreted by…

High Energy Astrophysical Phenomena · Physics 2024-06-07 Dmitry V. Malyshev

Recently, the High Altitude Water Cherenkov (HAWC) collaboration reported the discovery of the TeV halo around the Geminga pulsar. The TeV emission is believed to originate from inverse Compton scattering of pulsar-injected…

High Energy Astrophysical Phenomena · Physics 2019-04-26 Ruo-Yu Liu , Chong Ge , Xiao-Na Sun , Xiang-Yu Wang

Fermi LAT has discovered two extended gamma-ray bubbles above and below the galactic plane. We propose that their origin is due to the energy release in the Galactic center (GC) as a result of quasi-periodic star accretion onto the central…

Astrophysics of Galaxies · Physics 2011-09-14 D. O. Chernyshov , K. -S. Cheng , V. A. Dogiel , C. M. Ko , W. -H. Ip , Y. Wang

The Large High-Altitude Air Shower Observatory (LHAASO) recently published measurements of diffuse Galactic gamma-ray emission (DGE) in the 10-1000 TeV energy range. The measured DGE flux is significantly higher than the expectation from…

High Energy Astrophysical Phenomena · Physics 2024-08-27 Ensheng Chen , Kun Fang , Xiaojun Bi

The long-standing Galactic center gamma-ray excess could be explained by GeV dark matter (DM) annihilation, while the DM interpretation seems in tension with recent joint limits from different astronomical scale observations, such as dwarf…

High Energy Physics - Phenomenology · Physics 2021-07-07 Lian-Bao Jia , Tong Li

The Milky Way's galactic center is a highly dynamical, crowded environment. Gamma ray observations of this region, such as the excess of GeV scale gamma rays observed by Fermi LAT, have been of tremendous interest to both the high energy…

High Energy Astrophysical Phenomena · Physics 2025-09-24 Isabel S. Sands , Philip F. Hopkins , Sam B. Ponnada , Dusan Keres , Lina Necib , Yen-Hsing Julius Lin

Recent progress in pushing the sensitivity of the Imaging Atmospheric Cherenkov Technique into the 10 mCrab regime has enabled first sensitive observations of the innermost few 100 pc of the Milky Way in Very High Energy (VHE; >100 GeV)…

Astrophysics · Physics 2009-11-13 Christopher van Eldik

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

Several groups have recently claimed evidence for an unaccounted gamma-ray excess over {the} diffuse backgrounds at few GeV in {the} Fermi-LAT data in a region around the Galactic Center, consistent with a dark matter annihilation origin.…

High Energy Astrophysical Phenomena · Physics 2015-06-19 Jovana Petrovic , Pasquale Dario Serpico , Gabrijela Zaharijas

The Galactic Center Gamma-Ray Excess has a spectrum, angular distribution, and overall intensity that agree remarkably well with that expected from annihilating dark matter particles in the form of a $m_X \sim 50 \, {\rm GeV}$ thermal…

High Energy Astrophysical Phenomena · Physics 2022-09-30 Dan Hooper

We present a new Fermi-LAT analysis of the Galactic-center excess (GCE) designed to substantially reduce the dominant systematic uncertainties associated with interstellar-emission and source modeling in the inner Galaxy. Using an optimized…

High Energy Astrophysical Phenomena · Physics 2026-05-29 Mattia Di Mauro

Recent X-ray and gamma-ray observations of the Galactic center region by the ASCA and CGRO/EGRET instruments show evidence of 2--10 keV and $>1$ GeV continuum emission as well as 6.7 and 6.4 keV line emission from the inner $0.2^\circ$ of…

Astrophysics · Physics 2009-10-30 F. Yusef-Zadeh , W. Purcell , E. Gotthelf

We report the detection of gamma-ray emission by the Fermi Large Area Telescope (Fermi-LAT) towards the young massive star cluster RCW 38 in the 1-500 GeV photon energy range. We found spatially extended GeV emission towards the direction…

High Energy Astrophysical Phenomena · Physics 2024-03-29 Ting-Ting Ge , Xiao-Na Sun , Rui-Zhi Yang , Pak-Hin Thomas Tam , Ming-Xuan Lu , En-Wei Liang

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…

High Energy Astrophysical Phenomena · Physics 2018-09-05 Hamish A. Clark , Pat Scott , Roberto Trotta , Geraint F. Lewis