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The first data from the LHC Run-2 have shown a possible excess in diphoton events with invariant mass $\sim 750$ GeV, suggesting the existence of a new resonance which may decay dominantly into dark matter (DM) particles. We show in a…

High Energy Physics - Phenomenology · Physics 2016-06-15 Xian-Jun Huang , Wei-Hong Zhang , Yu-Feng Zhou

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…

Several groups of authors have analyzed Fermi LAT data in a region around the Galactic Center finding an unaccounted gamma-ray excess over diffuse backgrounds in the GeV energy range. It has been argued that it is difficult or even…

High Energy Astrophysical Phenomena · Physics 2015-06-23 Jovana Petrovic , Pasquale D. Serpico , Gabrijela Zaharijas

The Fermi Large Area Telescope (LAT) Collaboration has recently released the Third Catalog of Hard Fermi-LAT Sources (3FHL), which contains 1556 sources detected above 10 GeV with seven years of Pass 8 data. We investigate the source count…

High Energy Astrophysical Phenomena · Physics 2021-12-07 Mattia Di Mauro , Silvia Manconi , Hannes-S. Zechlin , Marco Ajello , Eric Charles , Fiorenza Donato

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

Observations using the Fermi Large Area Telescope (Fermi-LAT) have found a significant gamma-ray excess surrounding the center of the Milky Way (GC). One possible interpretation of this excess invokes gamma-ray emission from an undiscovered…

High Energy Astrophysical Phenomena · Physics 2016-03-23 Tim Linden

We have modelled the high-energy astrophysics of the inner 200 pc of the Galaxy with a view to explaining the diffuse, broad-band (radio continuum to TeV gamma-ray), non-thermal signal detected from this region. Our modelling pins down the…

High Energy Astrophysical Phenomena · Physics 2011-03-29 Roland M. Crocker

Galaxy clusters can be sources of high-energy (HE) $\gamma$-ray radiation, due to the efficient acceleration of particles exceeding EeV energies. At present, though, the only candidate for emitting HE $\gamma$-rays is the Coma cluster,…

High Energy Astrophysical Phenomena · Physics 2022-08-24 Vardan Baghmanyan , Davit Zargaryan , Felix Aharonian , Ruizhi Yang , Sabrina Casanova , Jonathan Mackey

The Fermi Large Area Telescope (LAT) has revealed a mysterious extended excess of GeV gamma-ray emission around the Galactic Center, which can potentially be explained by unresolved emission from a population of pulsars, particularly…

As recently shown, Fermi-LAT measurements of the diffuse gamma-ray emission from the Galaxy favor the presence of a smooth softening in the primary cosmic-ray spectrum with increasing Galactocentric distance. This result can be interpreted…

High Energy Astrophysical Phenomena · Physics 2016-06-22 Daniele Gaggero , Dario Grasso , Antonio Marinelli , Alfredo Urbano , Mauro Valli

We analyse the excess in the $\gamma$-ray emission from the center of our galaxy observed by Fermi-LAT in terms of dark matter annihilation within the scalar Higgs portal model. In particular, we include the astrophysical uncertainties from…

High Energy Physics - Phenomenology · Physics 2016-06-29 Alessandro Cuoco , Benedikt Eiteneuer , Jan Heisig , Michael Krämer

Using the EGRET data and an improved point source analysis, including an energy dependent point spread function and an unbinned maximum likelihood technique, we have been able to place considerably lower limits on the gamma ray flux from…

Astrophysics · Physics 2014-10-13 Dan Hooper , Brenda Dingus

Several groups have identified an extended excess of gamma rays over the modeled foreground and background emissions towards the Galactic center (GC) based on observations with the Fermi Large Area Telescope. This excess emission is…

High Energy Physics - Phenomenology · Physics 2015-04-28 Francesca Calore , Ilias Cholis , Christopher McCabe , Christoph Weniger

In the recent paper of Hooper & Goodenough (1010.2752) it was reported that gamma-ray emission from the Galactic Center region contains an excess compared to the contributions from the large-scale diffuse emission and known point sources.…

High Energy Physics - Phenomenology · Physics 2011-10-31 Alexey Boyarsky , Denys Malyshev , Oleg Ruchayskiy

We present a novel interpretation of the gamma-ray diffuse emission measured by H.E.S.S. in the Galactic Center (GC) region and the Galactic ridge. Our starting base is an updated analysis of PASS8 Fermi-LAT data, which allows to extend…

High Energy Astrophysical Phenomena · Physics 2017-07-27 D. Gaggero , D. Grasso , A. Marinelli , M. Taoso , A. Urbano , S. Ventura

Fermi Large Area Telescope data reveal an excess of GeV gamma rays from the direction of the Galactic Center and bulge. Several explanations have been proposed for this excess including an unresolved population of millisecond pulsars (MSPs)…

High Energy Astrophysical Phenomena · Physics 2017-08-15 Harrison Ploeg , Chris Gordon , Roland Crocker , Oscar Macias

It has long been suggested that nearby pulsars within $\sim 1 \,{\rm kpc}$ are the leading candidate of the 10-500 GeV cosmic-ray positron excess measured by PAMELA and other experiments. The recent measurement of surface brightness profile…

High Energy Astrophysical Phenomena · Physics 2019-06-26 Shao-Qiang Xi , Ruo-Yu Liu , Zhi-Qiu Huang , Kun Fang , Xiang-Yu Wang

We attempt to build a model that describes the {\it Fermi} galactic gamma-ray excess (FGCE) within a UV-complete Supersymmetric framework; we find this to be highly non-trivial. At the very least a successful Supersymmetric explanation must…

High Energy Physics - Phenomenology · Physics 2015-06-22 Matthew Cahill-Rowley , Jamie Gainer , JoAnne Hewett , Tom Rizzo

The Fermi Large Area Telescope (LAT) Collaboration has recently released a catalog of 360 sources detected above 50 GeV (2FHL). This catalog was obtained using 80 months of data re-processed with Pass 8, the newest event-level analysis,…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-20 LAT Collaboration

Faint $\gamma$-ray signatures emerge in Fermi-LAT data stacked scaled to the characteristic $R_{500}$ radii of MCXC galaxy clusters. This third paper in a series shows a $4.3\sigma$ excess of discrete 4FGL-DR4 catalog $\gamma$-ray sources…

High Energy Astrophysical Phenomena · Physics 2025-03-14 Uri Keshet