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In light of recent observations of an anomalous excess of high-energy positrons and electrons by the PAMELA and Fermi LAT experiments, we investigate exotic cosmic-ray signatures in scenarios with unstable dark matter that decays with an…

High Energy Physics - Phenomenology · Physics 2015-05-14 David Tran

The Fermi Gamma-ray Space Telescope was launched more than 13 years ago and since then it has dramatically changed our knowledge of the gamma-ray sky. With more than three billions photons from the whole sky, collected in the energy range…

High Energy Astrophysical Phenomena · Physics 2022-09-09 Giacomo Principe

The current version of the Fermi Large Area Telescope data (P8R2) has been publicly available since June 2015, with the caveat that the residual background of all event classes, except ULTRACLEANVETO, was not fully isotropic: it was…

Instrumentation and Methods for Astrophysics · Physics 2018-11-27 P. Bruel , T. H. Burnett , S. W. Digel , G. Johannesson , N. Omodei , M. Wood

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

Dusty, starforming galaxies and active galactic nuclei that contribute to the integrated background intensity at far-infrared wavelengths trace the large-scale structure. Below the point source detection limit, correlations in the…

Astrophysics · Physics 2008-11-26 Alexandre Amblard , Asantha Cooray

Over the past 16 years, the Fermi Large Area Telescope (LAT) has significantly advanced our view of the GeV gamma-ray sky, yet several key questions remain - such as the composition of the isotropic gamma-ray background, the origin of the…

High Energy Astrophysical Phenomena · Physics 2025-05-07 Christopher Eckner , Noemi Anau Montel , Florian List , Francesca Calore , Christoph Weniger

Gamma-ray searches for new physics such as dark matter are often driven by investigating the composition of the extragalactic gamma-ray background (EGB). Classic approaches to EGB decomposition manifest in resolving individual point sources…

High Energy Astrophysical Phenomena · Physics 2018-10-31 Hannes-S. Zechlin , Silvia Manconi , Fiorenza Donato

We search for spectral features in Fermi-LAT gamma-rays coming from regions corresponding to eighteen brightest nearby galaxy clusters determined by the magnitude of their signal line-of-site integrals. We observe a double peak-like excess…

High Energy Astrophysical Phenomena · Physics 2015-06-05 Andi Hektor , Martti Raidal , Elmo Tempel

The Large Area Telescope on the Fermi gamma-ray Space Telescope provides unprecedented sensitivity for all-sky monitoring of gamma-ray activity. It has detected a few Galactic sources, including 2 gamma-ray binaries and a microquasar. In…

High Energy Astrophysical Phenomena · Physics 2016-11-15 Sylvain Chaty

Our understanding of the $\gamma$-ray sky has greatly advanced, yet studying the unresolved $\gamma$-ray background (UGRB) can unveil the nature of the faintest $\gamma$-ray source populations in the Universe. Statistical cross-correlations…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-24 B. Thakore , M. Regis , M. Negro , S. Camera , D. Gruen , N. Fornengo , A. Roodman

During its first four years of scientific observations, the Fermi Large Area Telescope (Fermi-LAT) detected 3033 $\gamma$-ray sources above a 4$\sigma$ significance level. Although most of the extra-Galactic sources are active galactic…

High Energy Astrophysical Phenomena · Physics 2019-08-15 G. La Mura , G. Chiaro , S. Ciroi , P. Rafanelli , D. Salvetti , M. Berton , V. Cracco

The galactic diffuse $\gamma$-ray emission, as seen by Fermi Large Area Telescope (LAT), shows a sharp peak in the region around 4 kpc from the Galactic center, which can be interpreted either as due to an enhanced density of cosmic-ray…

High Energy Astrophysical Phenomena · Physics 2021-03-23 Giada Peron , Felix Aharonian , Sabrina Casanova , Ruizhi Yang , Roberta Zanin

We have used measurements by the Fermi Large Area Telescope (LAT) to study the interstellar gamma-ray emission in a region of the second Galactic quadrant, at 100 deg < l < 145 deg and -15 deg < b < 30 deg. This region encompasses the…

High Energy Astrophysical Phenomena · Physics 2019-08-13 L. Tibaldo , I. A. Grenier

Launched on June 11, 2008, the LAT instrument onboard the $Fermi$ Gamma-ray Space Telescope has provided a rare opportunity to study high energy photon emission from gamma-ray bursts. Although the majority of such events (27) have been iden…

High Energy Astrophysical Phenomena · Physics 2015-06-04 Weikang Zheng , Carl W. Akerlof , Shashi B. Pandey , Timothy A. McKay , Binbin Zhang , Bing Zhang , Takanori Sakamoto

We present deep optical and X-ray follow-up observations of the bright unassociated Fermi-LAT gammaray source 1FGL J1311.7-3429. The source was already known as an unidentified EGRET source (3EG J1314-3431, EGR J1314-3417), hence its nature…

High Energy Astrophysical Phenomena · Physics 2015-06-11 J. Kataoka , Y. Yatsu , N. Kawai , Y. Urata , C. C. Cheung , Y. Takahashi , K. Maeda , T. Totani , R. Makiya , H. Hanayama , T. Miyaji , A. Tsai

The Galactic diffuse emission is potentially able to reveal much about the sources and propagation of cosmic rays (CR), their spectra and intensities in distant locations. It can possibly unveil WIMP dark matter (DM) through its…

Astrophysics · Physics 2016-08-30 I. V. Moskalenko , A. W. Strong

Here is reviewed our current understanding of Galactic and extragalactic diffuse gamma-ray emission. The spectrum of the extragalactic gamma-ray background above 30 MeV can be well described by a power law with photon index s=2.1. In the…

Astrophysics · Physics 2007-05-23 Martin Pohl

The nature of the Isotropic $\gamma$-ray Background (IGRB) measured by the Large Area Telescope (LAT) on the Fermi $\gamma$-ray space Telescope ({\it Fermi}) remains partially unexplained. Non-negligible contributions may originate from…

Cosmology and Nongalactic Astrophysics · Physics 2014-02-05 Torsten Bringmann , Francesca Calore , Mattia Di Mauro , Fiorenza Donato

Recent Fermi results have focused attention on gamma-ray burst's (GRB) prompt emission phase, which is rich in phenomenology and poorly understood. The broad band spectra observed by Fermi does not fit into any of the frameworks of existing…

High Energy Astrophysical Phenomena · Physics 2011-11-16 Asaf Pe'er

The Fermi Gamma-ray Observatory discovered about a thousand extragalactic sources emitting energy from 100 MeV to 100 GeV. The majority of these sources belong to the class of blazars characterized by a quasi-featureless optical spectrum…

Astrophysics of Galaxies · Physics 2017-11-02 Simona Paiano , Renato Falomo , Marco Landoni , Aldo Treves , Riccardo Scarpa