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The so-called "GeV-excess" of the diffuse Galactic gamma-ray emission is studied with a spectral template fit based on energy spectra. The spectral templates can be obtained in a data-driven way from the gamma-ray data, which avoids the use…

High Energy Astrophysical Phenomena · Physics 2017-09-13 Wim de Boer , Leo Bosse , Iris Gebauer , Alexander Neumann , Peter Biermann

Recent observations of gamma-rays with the Fermi Large Area Telescope (LAT) in the direction of the inner Galaxy revealed a mysterious GeV excess. Its intensity is significantly above predictions of the standard model of cosmic rays (CRs)…

High Energy Astrophysical Phenomena · Physics 2021-08-10 Dmitry O. Chernyshov , Andrei E. Egorov , Vladimir A. Dogiel , Alexei V. Ivlev

Observations by the Fermi-LAT have uncovered a bright, spherically symmetric excess surrounding the center of the Milky Way galaxy. The spectrum of the gamma-ray excess peaks sharply at an energy ~2 GeV, exhibiting a hard spectrum at lower…

High Energy Astrophysical Phenomena · Physics 2017-02-28 Tim Linden , Nicholas L. Rodd , Benjamin R. Safdi , Tracy R. Slatyer

The region around the Galactic center (GC) is now well established to be brighter at energies of a few GeV than expected from conventional models of diffuse gamma-ray emission and catalogs of known gamma-ray sources. We study the GeV excess…

High Energy Astrophysical Phenomena · Physics 2017-06-27 LAT Collaboration

The Fermi Large Area Telescope data appear to have an excess of gamma rays from the inner 150 pc of the Galactic Center (GC). The main explanations proposed for this are: an unresolved population of millisecond pulsars (MSPs), dark matter…

High Energy Astrophysical Phenomena · Physics 2014-10-30 Chris Gordon , Oscar Macias

Nearby pulsars within $\sim1\,{\rm kpc}$ are considered to be possible sources of 10-500 GeV cosmic-ray positron excess measured by PAMELA and AMS-02. A TeV halo around Geminga is detected by HAWC, and the measurements of its surface…

High Energy Astrophysical Phenomena · Physics 2026-02-25 Yu Meng , Yun-Feng Liang , Ben-Yang Zhu , Xiao-Na Sun , En-Wei Liang

The Fermi-LAT \gamma-ray data have been used to study the morphological and spectral features of the so-called GeV excess - a diffuse radiation component recently discovered towards the Galactic centre. We used the likelihood method to…

High Energy Astrophysical Phenomena · Physics 2016-04-27 Rui-zhi Yang , Felix Aharonian

Past studies have identified a spatially extended excess of $\sim$1-3 GeV gamma rays from the region surrounding the Galactic Center, consistent with the emission expected from annihilating dark matter. We revisit and scrutinize this signal…

High Energy Astrophysical Phenomena · Physics 2016-02-24 Tansu Daylan , Douglas P. Finkbeiner , Dan Hooper , Tim Linden , Stephen K. N. Portillo , Nicholas L. Rodd , Tracy R. Slatyer

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

The diffuse gamma-ray emission between 10 and 1000 TeV from the Galactic plane was recently measured by the Large High Altitude Air Shower Observatory (LHAASO). These observations will help tremendously in constraining the propagation and…

High Energy Astrophysical Phenomena · Physics 2023-11-06 Rui Zhang , Xiaoyuan Huang , Zhi-Hui Xu , Shiping Zhao , Qiang Yuan

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

Over the past few years, there has been a hint of the $\gamma$-ray excess observed by the Fermi-LAT satellite borne telescope from the regions surrounding the Galactic Centre at an energy range $\sim 1$-$3$ GeV. The nature of this excess…

High Energy Physics - Phenomenology · Physics 2016-03-21 Anirban Biswas

Various theoretical models predict the existence of extended $\gamma$-ray halo around normal galaxies that could be produced by interactions of cosmic rays with the circumgalactic medium or by annihilation or decay of hypothetical dark…

High Energy Astrophysical Phenomena · Physics 2026-04-03 M. S. Pshirkov , B. A. Nizamov

Several groups have analyzed the publicly-available Fermi-LAT data and reported a spatially extended $\gamma-$ray excess of around $1-3$ GeV from the region surrounding the Galactic Center that might originate from annihilation of dark…

High Energy Astrophysical Phenomena · Physics 2015-06-24 Bei Zhou , Yun-Feng Liang , Xiaoyuan Huang , Xiang Li , Yi-Zhong Fan , Lei Feng , Jin Chang

The possible gamma-ray excess in the inner Galaxy and the Galactic center (GC) suggested by Fermi-LAT observations has triggered a large number of studies. It has been interpreted as a variety of different phenomena such as a signal from…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Francesca Calore , Ilias Cholis , Christoph Weniger

One of the most prominent features of the $\gamma$-ray sky is the emission from our own Galaxy. The Galactic plane has been observed by Fermi-LAT in GeV and H.E.S.S. in TeV light. Fermi has modeled the Galactic emission as the sum of a…

High Energy Astrophysical Phenomena · Physics 2015-06-09 Ellis Owen , Christoph Deil , Axel Donath , Régis Terrier

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

Cosmic rays up to at least PeV energies are usually described in the framework of an elementary scenario that involves acceleration by objects that are located in the disk of the Milky Way, such as supernova remnants or massive star-forming…

High Energy Astrophysical Phenomena · Physics 2019-08-14 L. Tibaldo , S. W. Digel

Fermi-LAT observations of the Galactic Center (GC) have revealed a spherically- symmetric excess of GeV gamma rays extending to at least 10 deg from the dynamical center of the Galaxy. A critical uncertainty in extracting the intensity,…

High Energy Astrophysical Phenomena · Physics 2016-09-14 Eric Carlson , Tim Linden , Stefano Profumo

The High-Energy Stereoscopic System (HESS) has detected diffuse TeV emission correlated with the distribution of molecular gas along the Ridge at the Galactic Center. Diffuse, non-thermal emission is also seen by the Fermi large area…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Oscar Macias , Chris Gordon , Roland Crocker , Stefano Profumo
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