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Related papers: A Search for Gamma-Ray Emission from Variable or T…

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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 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

We study diffuse gamma-ray emission at intermediate Galactic latitudes measured by the Fermi Large Area Telescope with the aim of searching for a signal from dark matter annihilation or decay. In the absence of a robust dark matter signal,…

High Energy Astrophysical Phenomena · Physics 2013-04-10 G. Zaharijas , J. Conrad , A. Cuoco , Z. Yang

Recently, the {\it{Fermi}} space telescope has discovered two large $\gamma$-ray emission regions, the so-called "Fermi bubbles", that extend up to $\sim 50^\circ$ above and below the Galactic center. The $\gamma$-ray emission from the…

High Energy Astrophysical Phenomena · Physics 2015-06-15 Satyendra Thoudam

The extragalactic gamma-ray sky is dominated by the emission arising from blazars, one of the most peculiar classes of radio-loud active galaxies. Since the launch of Fermi several methods were developed to search for blazars as potential…

High Energy Astrophysical Phenomena · Physics 2015-06-24 F. Ricci , F. Massaro , M. Landoni , R. D'Abrusco , D. Milisavljevic , D. Stern , N. Masetti , A. Paggi , Howard A. Smith , G. Tosti

Giant radio sources, including galaxies and quasars (hereafter GRGs), are active galactic nuclei (AGN) hosting relativistic jets with source sizes exceeding the projected length of 0.7 Mpc. They are crucial to understanding the evolution of…

High Energy Astrophysical Phenomena · Physics 2025-07-08 Vaidehi S. Paliya , D. J. Saikia , Gabriele Bruni , Alberto Dominguez , C. S. Stalin

Context. The advent of Fermi is changing our understanding on the radio and gamma-ray emission in Active Galactic Nuclei. Contrary to pre-Fermi ideas, BL Lac objects are found to be the most abundant emitters in the gamma-ray band. However,…

High Energy Astrophysical Phenomena · Physics 2015-06-17 E. Liuzzo , M. Giroletti , G. Giovannini , B. Boccardi , S. Tamburri , G. B. Taylor , C. Casadio , M. Kadler , G. Tosti , A. Mignano

"Diffuse" gamma rays consist of several components: truly diffuse emission from the interstellar medium, the extragalactic background, whose origin is not firmly established yet, and the contribution from unresolved and faint Galactic point…

Astrophysics · Physics 2015-06-24 I. V. Moskalenko , A. W. Strong , O. Reimer

We explore potential of current and next-generation gamma-ray telescopes for the detection of weak magnetic fields in the intergalactic medium. We demonstrate that using two complementary techniques, observation of extended emission around…

Cosmology and Nongalactic Astrophysics · Physics 2009-12-31 A. Neronov , D. Semikoz

Continuum gamma-ray emission produced by interactions of cosmic rays with interstellar matter and radiation fields is a probe of non-thermal particle populations in galaxies. After decades of continuous improvements in experimental…

High Energy Astrophysical Phenomena · Physics 2021-05-12 Luigi Tibaldo , Daniele Gaggero , Pierrick Martin

We discuss the relation between cosmic-ray induced interstellar gamma-ray and radio emission from our Galaxy, and emphasize the importance of their parallel study. We give an overview of results from Fermi-LAT on the interstellar gamma-ray…

High Energy Astrophysical Phenomena · Physics 2015-06-15 Elena Orlando , Andrew W. Strong

The Fermi Gamma-ray Space Telescope, a key mission in multiwavelength and multimessenger studies, has been surveying the gamma-ray sky from its low-Earth orbit since 2008. Its two scientific instruments, the Gamma-ray Burst Monitor (GBM)…

High Energy Astrophysical Phenomena · Physics 2023-04-05 David J. Thompson , Colleen A. Wilson-Hodge

More than 90% of the Galactic gas-related gamma-ray emissivity above 1 GeV is attributed to the decay of neutral pions formed in collisions between cosmic rays and interstellar matter, with lepton-induced processes becoming increasingly…

High Energy Astrophysical Phenomena · Physics 2019-08-13 C. D. Dermer , A. W. Strong , E. Orlando , L. Tibaldo

The study of Galactic diffuse $\gamma$ radiation combined with the knowledge of the distribution of the molecular hydrogen in the Galaxy offers a unique tool to probe the cosmic ray flux in the Galaxy. A methodology to study the level of…

Astrophysics · Physics 2009-11-13 S. Casanova , S. Gabici , F. A. Aharonian , K. Torii , Y. Fukui , T. Onishi , H. Yamamoto , A. Kawamura

The advent of Fermi is changing our understanding on the radio and gamma-ray emission in Active Galactic Nuclei. In fact, contrary to previous campaigns, Fermi mission reveals that BL Lac objects are the most abundant emitters in gamma-ray…

High Energy Astrophysical Phenomena · Physics 2013-06-05 E. Liuzzo , B. Boccardi , M. Giroletti , G. Giovannini

The launch of the Fermi gamma-ray space telescope and the imaging air Cerenkov telescopes H.E.S.S., MAGIC, and VERITAS have substantially transformed our knowledge of gamma-ray sources in the last decade. The extragalactic gamma-ray sky is…

High Energy Astrophysical Phenomena · Physics 2013-09-02 C. Pfrommer

As the highest-energy photons, gamma rays have an inherent interest to astrophysicists and particle physicists studying high-energy, nonthermal processes. Gamma-ray telescopes complement those at other wavelengths, especially radio,…

Astrophysics · Physics 2009-11-10 David J. Thompson

Clusters of galaxies and the large scale filaments that connect neighboring clusters are expected to be sites of acceleration of charged particles and sources of non-thermal radiation from radio frequencies to gamma rays. Gamma rays are…

Astrophysics · Physics 2009-11-13 Pasquale Blasi , Stefano Gabici , Gianfranco Brunetti

With a decade of gamma-ray data from the Fermi-LAT telescope, we can now hope to answer how well we know the local Universe at gamma-ray frequencies. On the other hand, with gamma-ray data alone it is not possible to directly access the…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-27 Simone Ammazzalorso , Nicolao Fornengo , Shunsaku Horiuchi , Marco Regis

Gamma-ray studies are an essential tool in our search for the origin of cosmic rays. Instruments like the Fermi-LAT, H.E.S.S., MAGIC and VERITAS have revolutionized our understanding of the high energy Universe. This paper describes the…

High Energy Astrophysical Phenomena · Physics 2012-04-23 Stefan Funk