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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

We report the Fermi Large Area Telescope (Fermi-LAT) detection of the gamma-ray emission towards the young massive star cluster RSGC 1. Using the latest source catalog and diffuse background models, we found that the diffuse gamma-ray…

High Energy Astrophysical Phenomena · Physics 2020-06-04 Xiao-Na Sun , Rui-Zhi Yang , Xiang-Yu Wang

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

We analyze 15 years of Fermi-LAT data and produce a detailed model of the Sun's inverse-Compton scattering emission (solar halo), which is powered by interactions between ambient cosmic-ray electrons and positrons with sunlight. By…

High Energy Astrophysical Phenomena · Physics 2026-01-28 Tim Linden , Jung-Tsung Li , Bei Zhou , Isabelle John , Milena Crnogorčević , Annika H. G. Peter , John F. Beacom

We report the detection of gamma-ray emission by the Fermi Large Area Telescope (Fermi-LAT) towards the young massive star cluster RCW 38 in the 1-500 GeV photon energy range. We found spatially extended GeV emission towards the direction…

High Energy Astrophysical Phenomena · Physics 2024-03-29 Ting-Ting Ge , Xiao-Na Sun , Rui-Zhi Yang , Pak-Hin Thomas Tam , Ming-Xuan Lu , En-Wei Liang

We report the detection of high-energy gamma rays from the quiescent Sun with the Large Area Telescope (LAT) on board the Fermi Gamma-Ray Space Telescope (Fermi) during the first 18 months of the mission. These observations correspond to…

High Energy Astrophysical Phenomena · Physics 2011-06-08 A. A. Abdo

The study of the quiet Sun in gamma rays started over a decade ago, and rapidly gained a wide interest. Gamma rays from the quiet Sun are produced by Cosmic Rays (CRs) interacting with its surface (disk component) and with its photon field…

High Energy Astrophysical Phenomena · Physics 2021-04-05 Elena Orlando , Andrew Strong

Hadron emission from supernova remnant (SNR)-molecular cloud (MC) association systems has been widely regarded as a probe of the shock-accelerated cosmic-ray protons. Here, we report on the detection of a {\gamma}-ray emission source, with…

High Energy Astrophysical Phenomena · Physics 2015-08-19 Bing Liu , Yang Chen , Xiao Zhang , Gao-Yuan Zhang , Yi Xing , Thomas G. Pannuti

Observations by the Large Area Telescope (LAT) on the \textit{Fermi} mission of diffuse $\gamma$-rays in a mid-latitude region in the third quadrant (Galactic longitude $l$ from $200\arcdeg$ to $260\arcdeg$ and latitude $| b |$ from…

High Energy Astrophysical Phenomena · Physics 2009-12-04 A. A. Abdo

The {\gamma}-ray sky can be decomposed into individually detected sources, diffuse emission attributed to the interactions of Galactic cosmic rays with gas and radiation fields, and a residual all-sky emission component commonly called the…

High Energy Astrophysical Phenomena · Physics 2015-06-02 The Fermi LAT collaboration , M. Ackermann , M. Ajello , A. Albert , W. B. Atwood , L. Baldini , J. Ballet , G. Barbiellini , D. Bastieri , K. Bechtol , R. Bellazzini , E. Bissaldi , R. D. Blandford , E. D. Bloom , E. Bottacini , T. J. Brandt , J. Bregeon , P. Bruel , R. Buehler , S. Buson , G. A. Caliandro , R. A. Cameron , M. Caragiulo , P. A. Caraveo , E. Cavazzuti , C. Cecchi , E. Charles , A. Chekhtman , J. Chiang , G. Chiaro , S. Ciprini , R. Claus , J. Cohen-Tanugi , J. Conrad , A. Cuoco , S. Cutini , F. D'Ammando , A. de Angelis , F. de Palma , C. D. Dermer , S. W. Digel , E. do Couto e Silva , P. S. Drell , C. Favuzzi , E. C. Ferrara , W. B. Focke , A. Franckowiak , Y. Fukazawa , S. Funk , P. Fusco , F. Gargano , D. Gasparrini , S. Germani , N. Giglietto , P. Giommi , F. Giordano , M. Giroletti , G. Godfrey , G. A. Gomez-Vargas , I. A. Grenier , S. Guiriec , M. Gustafsson , D. Hadasch , K. Hayashi , E. Hays , J. W. Hewitt , P. Ippoliti , T. Jogler , G. Jóhannesson , A. S. Johnson , W. N. Johnson , T. Kamae , J. Kataoka , J. Knödlseder , M. Kuss , S. Larsson , L. Latronico , J. Li , L. Li , F. Longo , F. Loparco , B. Lott , M. N. Lovellette , P. Lubrano , G. M. Madejski , A. Manfreda , F. Massaro , M. Mayer , M. N. Mazziotta , J. E. McEnery , P. F. Michelson , W. Mitthumsiri , T. Mizuno , A. A. Moiseev , M. E. Monzani , A. Morselli , I. V. Moskalenko , S. Murgia , R. Nemmen , E. Nuss , T. Ohsugi , N. Omodei , E. Orlando , J. F. Ormes , D. Paneque , J. H. Panetta , J. S. Perkins , M. Pesce-Rollins , F. Piron , G. Pivato , T. A. Porter , S. Rainò , R. Rando , M. Razzano , S. Razzaque , A. Reimer , O. Reimer , T. Reposeur , S. Ritz , R. W. Romani , M. Sánchez-Conde , M. Schaal , A. Schulz , C. Sgrò , E. J. Siskind , G. Spandre , P. Spinelli , A. W. Strong , D. J. Suson , H. Takahashi , J. G. Thayer , J. B. Thayer , L. Tibaldo , M. Tinivella , D. F. Torres , G. Tosti , E. Troja , Y. Uchiyama , G. Vianello , M. Werner , B. L. Winer , K. S. Wood , M. Wood , G. Zaharijas , S. Zimmer

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

The first evidence of the gamma-ray emission from the quiescent Sun was found in the archival EGRET data that was later confirmed by Fermi-LAT observations with high significance. This emission is produced by Galactic cosmic rays (CRs)…

High Energy Astrophysical Phenomena · Physics 2017-12-29 Elena Orlando , Nicola Giglietto , Igor Moskalenko , Silvia Raino' , Andrew Strong

This paper is in response to a technical paper, entitled "Evidence for a New Component of High-Energy Solar Gamma-Ray Production" (Linden, et al., 2018). An article in Scientific American entitled "The Sun Is Spitting Out Strange Patterns…

Solar and Stellar Astrophysics · Physics 2019-02-11 Gregory S Glenn

The Fermi-LAT data accumulated over 7 years of {\gamma}-ray observations, together with the high resolution gas (CO & HI) and the dust opacity maps, are used to study the emissivity of {\gamma}-rays induced by interactions of cosmic rays…

High Energy Astrophysical Phenomena · Physics 2016-06-22 Rui-zhi Yang , Felix Aharonian , Carmelo Evoli

Most of the diffuse Galactic GeV gamma-ray emission is produced via collisions of cosmic ray (CR) protons with ISM protons. As such the observed spectra of the gamma-rays and the CRs should be strongly linked. Recent observations of…

High Energy Astrophysical Phenomena · Physics 2017-02-01 Lara Nava , David Benyamin , Tsvi Piran , Nir J. Shaviv

The "GeV-excess" of the diffuse gamma-rays in the halo is studied with a template fit based on energy spectra for each possible process of gamma-ray emission. Such a fit allows to determine the background and signal simultaneously, so the…

High Energy Astrophysical Phenomena · Physics 2016-10-28 Wim de Boer , Iris Gebauer , Alexander Neumann , Peter L. Biermann

The Fermi Large Area Telescope (LAT) observed two bright X-class solar flares on 2012 March 7, and detected gamma-rays up to 4 GeV. We detected gamma-rays both during the impulsive and temporally-extended emission phases, with emission…

High Energy Astrophysical Phenomena · Physics 2017-02-22 LAT collaboration

The diffuse Galactic gamma-ray emission is produced by cosmic rays (CRs) interacting with the interstellar gas and radiation field. Measurements by the Energetic Gamma-Ray Experiment Telescope (EGRET) instrument on the Compton Gamma-Ray…

High Energy Astrophysical Phenomena · Physics 2019-08-13 T. A. Porter

Cosmic rays in the inner solar system are subject to deflection by both the geomagnetic and interplanetary magnetic fields, and simultaneously interact with the Sun's photosphere resulting in the production of gamma rays. This phenomenon…

High Energy Astrophysical Phenomena · Physics 2017-08-15 Mehr Un Nisa

The LAT instrument on the Fermi Gamma-Ray Space Telescope is performing an all-sky survey from 20 MeV to 300 GeV with unprecedented statistics and angular resolution. This is providing a wealth of new information on the non-thermal emission…

High Energy Astrophysical Phenomena · Physics 2019-08-14 A. W. Strong