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The physical origin of the >0.1 GeV emission detected from Gamma-Ray Bursts (GRBs) by the Fermi satellite has not yet been completely understood. In this work we consider the GeV light curves of ten GRBs with measured redshift detected by…

High Energy Astrophysical Phenomena · Physics 2015-06-22 L. Nava , G. Vianello , N. Omodei , G. Ghisellini , G. Ghirlanda , A. Celotti , F. Longo , R. Desiante , R. Barniol Duran

The spectrum of an isotropic extragalactic {\gamma}-ray background (EGB) has been measured by the Fermi-LAT telescope at high latitudes. Two new models for the EGB are derived from the subraction of unresolved point sources and…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-15 Francesca Calore , Valentina De Romeri , Fiorenza Donato

We report the discovery of high-energy (E>100 MeV) gamma-ray emission from NGC 1275, a giant elliptical galaxy lying at the center of the Perseus cluster of galaxies, based on observations made with the Large Area Telescope (LAT) of the…

High Energy Astrophysical Phenomena · Physics 2012-08-27 LAT Collaboration , A. A. Abdo , H. D. Aller , M. F. Aller , K. I. Kellermann , Y. Y. Kovalev , Y. A. Kovalev , M. L. Lister , A. B. Pushkarev

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

We report the discovery of a $\sim$ $3.4\degr$-wide region of high-energy emission in data from the \emph{Fermi} LAT satellite. The centroid of the emission is located in the Southern Hemisphere sky, a few degrees away from the plane of the…

High Energy Astrophysical Phenomena · Physics 2018-01-26 Miguel Araya

We analyze 5-year (63 months) data of the Large Area Telescope on board Fermi satellite from the Coma galaxy cluster in the energy range between 100 MeV and 100 GeV. The likelihood analyses are performed with several templates motivated by…

High Energy Astrophysical Phenomena · Physics 2014-04-15 Fabio Zandanel , Shin'ichiro Ando

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

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 report on preliminary results from the Fermi High-Latitude Extended Sources Catalog (FHES), a comprehensive search for spatially extended gamma-ray sources at high Galactic latitudes ($|b|>5^\circ$) based on data from the Fermi Large…

High Energy Astrophysical Phenomena · Physics 2019-08-14 Matthew Wood , Jonathan Biteau , Regina Caputo , Mattia Di Mauro , Manuel Meyer

The density spike of dark matter (DM) in the subparsec region near the supermassive black hole at the Galactic Center can provide potentially observable gamma-ray signals coming from DM annihilations. Taking Fermi-$LAT$ data for the…

High Energy Physics - Phenomenology · Physics 2018-08-08 Pearl Sandick , Kuver Sinha , Takahiro Yamamoto

We combine adaptive template fitting and pixel count statistics in order to assess the nature of the Galactic center excess in Fermi-LAT data. We reconstruct the flux distribution of point sources well below the Fermi-LAT detection…

High Energy Astrophysical Phenomena · Physics 2021-10-29 Francesca Calore , Fiorenza Donato , Silvia Manconi

Recently the study of anomalous gamma-ray emission in the regions surrounding the galactic center has drawn a lot of attention as it points out that the excess of $\sim 1-3$ GeV gamma-ray in the low latitude is consistent with the emission…

High Energy Physics - Phenomenology · Physics 2015-04-09 Tanushree Basak , Tanmoy Mondal

N-body simulations predict that galaxies at the Milky Way scale host a large number of dark matter (DM) subhalos. Some of these subhalos, if they are massive enough or close enough to the Earth, might be detectable in $\gamma$ rays due to…

High Energy Astrophysical Phenomena · Physics 2016-12-21 Yuan-Peng Wang , Kai-Kai Duan , Peng-Xiong Ma , Yun-Feng Liang , Zhao-Qiang Shen , Shang Li , Chuan Yue , Qiang Yuan , Jing-Jing Zang , Yi-Zhong Fan , Jin Chang

New bounds on decaying Dark Matter are derived from the gamma-ray measurements of (i) the isotropic residual (extragalactic) background by Fermi and (ii) the Fornax galaxy cluster by H.E.S.S. We find that those from (i) are among the most…

High Energy Astrophysical Phenomena · Physics 2013-07-31 E. Moulin , M. Cirelli , P. Panci , P. Serpico , A. Viana

An anomalous emission component at energies of a few GeV and located towards the inner Galaxy is present in the Fermi-LAT data. It is known as the Fermi-LAT GeV excess. Using almost 8 years of data we reanalyze the characteristics of this…

High Energy Astrophysical Phenomena · Physics 2018-08-10 Richard Bartels , Emma Storm , Christoph Weniger , Francesca Calore

In a previous paper, we pointed out that the gamma-ray source 3FGL J2212.5+0703 shows evidence of being spatially extended. If a gamma-ray source without detectable emission at other wavelengths were unambiguously determined to be spatially…

High Energy Astrophysical Phenomena · Physics 2016-06-01 Bridget Bertoni , Dan Hooper , Tim Linden

Massive star clusters (SCs) have been proposed as additional contributors to Galactic Cosmic rays (CRs), to overcome the limitations of supernova remnants (SNR) to reach the highest energy end of the Galactic CR spectrum. Thanks to fast…

High Energy Astrophysical Phenomena · Physics 2025-01-22 Giada Peron , Giovanni Morlino , Elena Amato , Stefano Menchiari

Excess of gamma rays 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 spherical morphology and the spectral energy distribution with a…

High Energy Astrophysical Phenomena · Physics 2025-03-13 Dmitry V. Malyshev

This study reanalyzes the detection prospects of dark matter (DM) annihilation signals in the Galactic Center, focusing on velocity-dependent dynamics within a spike density near the supermassive black hole (Sgr~A$^{\star}$). We investigate…

High Energy Physics - Phenomenology · Physics 2024-10-25 MeiWen Yang , Zhi-Qi Guo , Xiao-Yi Luo , Zhao-Qiang Shen , Zi-Qing Xia , Chih-Ting Lu , Yue-Lin Sming Tsai , Yi-Zhong Fan

The center of the Milky Way is offering one of the most striking mystery in Astroparticle Physics. An excess of gamma rays (GCE) has been measured by several groups in the data collected by the Fermi Large Area Telescope (LAT) towards the…

High Energy Astrophysical Phenomena · Physics 2020-11-18 Mattia Di Mauro