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We derive observational consequences of the hypothesis that cosmic rays (CR's) of energy $>10^{19}eV$ originate in the same cosmological objects producing gamma-ray bursts (GRB's). Inter-galactic magnetic fields $\gtrsim 10^{-12} G$ are…

Astrophysics · Physics 2009-10-28 Jordi Miralda-Escude , Eli Waxman

The origin of the diffuse gamma-ray background (DGRB), the one that remains after subtracting all individual sources from observed gamma-ray sky, is unknown. The DGRB possibly encompasses contributions from different source populations such…

High Energy Astrophysical Phenomena · Physics 2023-05-02 Saqib Hussain , Rafael Alves Batista , Elisabete M. de Gouveia Dal Pino , Klaus Dolag

Recent EGRET observations of the diffuse Galactic gamma-ray emission reveal a spectrum which is incompatible with the assumption that the cosmic ray spectra measured locally hold throughout the Galaxy: the spectrum above 1 GeV, where the…

Astrophysics · Physics 2009-11-07 I. Büsching , M. Pohl , R. Schlickeiser

The secondary/primary cosmic-ray ratios and the diffuse backgrounds of gamma rays and neutrinos provide us with complementary information about the transport of Galactic cosmic rays~(CRs). We used the recent measurement of the diffuse gamma…

High Energy Astrophysical Phenomena · Physics 2025-06-13 Antonio Ambrosone , Carmelo Evoli , Benedikt Schroer , Pasquale Blasi

Low-frequency radio observations of diffuse synchrotron radiation offer a unique vantage point for investigating the intricate relationship between gas and magnetic fields in the formation of structures within the Galaxy, spanning from the…

Astrophysics of Galaxies · Physics 2024-05-29 Andrea Bracco , Marco Padovani , Daniele Galli

A subset of the unidentified EGRET gamma-ray sources with no active galactic nucleus or other conspicuous counterpart appears to be concentrated at medium latitudes. Their long-term variability and their spatial distribution indicate that…

Astrophysics · Physics 2009-11-10 I. A. Grenier , M. M. Kaufman Bernado , G. E. Romero

Nearby sources of cosmic rays up to a ZeV(=10^21 eV) could be observed with a multi-messenger approach including secondary gamma-rays and neutrinos. If cosmic rays above ~10^18 eV are produced in magnetized environments such as galaxy…

Astrophysics · Physics 2007-05-23 Eric Armengaud , Guenter Sigl , Francesco Miniati

Recent observations of the diffuse Galactic gamma-ray emission by the Fermi-LAT satellite have shown significant deviations from models which assume the same diffusion properties for cosmic rays (CR) throughout the Galaxy. We explore the…

High Energy Astrophysical Phenomena · Physics 2017-08-17 G. Morlino , M. D'Angelo , P. Blasi , E. Amato

We perform a consistent modeling of cosmic ray electrons, positrons and of the radio emission of the Galaxy. For the time we reproduce all relevant data sets between 1 GeV and 1 TeV including the recent AMS-02 positron fraction results. We…

High Energy Astrophysical Phenomena · Physics 2013-07-01 D. Grasso , G. Di Bernardo , C. Evoli , D. Gaggero , L. Maccione

The diffuse extragalactic gamma-ray background (EGRB) above 100 MeV encodes unique information about high-energy processes in the universe. Numerous sources for the EGRB have been proposed, but the two systems which are certain to make some…

Astrophysics · Physics 2009-11-07 Vasiliki Pavlidou , Brian D. Fields

We study the high latitude (|b|>10) diffuse gamma-ray emission in the Galaxy in light of the recently published data from the Fermi collaboration at energies between 100 MeV and 100 GeV. The unprecedented accuracy in these measurements…

High Energy Astrophysical Phenomena · Physics 2013-04-16 I. Cholis , M. Tavakoli , C. Evoli , L. Maccione , P. Ullio

Summary of abstract: The existence of a new population of yet unrecognized x-ray sources has been often suggested to resolve some pecularities in the properties of the x-ray background (XRB), and has recently been indicated by an analysis…

Astrophysics · Physics 2009-10-22 Eyal Maoz , Jonathan Grindlay

We have developed a model which aims to reproduce observational data of many kinds related to cosmic-ray origin and propagation: direct measurements of nuclei, antiprotons, electrons and positrons, gamma-rays, and synchrotron radiation. Our…

Astrophysics · Physics 2007-05-23 A. W. Strong , I. V. Moskalenko

Most models of the origin of ultra high energy cosmic rays rely on the existence of luminous extragalactic sources. Cosmic rays escaping the galaxy where the source is located produce a sufficiently large electric current to justify the…

High Energy Astrophysical Phenomena · Physics 2015-08-20 P. Blasi , E. Amato , M. D'Angelo

We studied the spectral signature of different components of the Diffuse X-ray Background (DXB), including Local Hot Bubble (LHB), Solar Wind Charge Exchange (SWCX), Galactic Halo, and typically unresolved point sources (galaxies and AGN),…

High Energy Astrophysical Phenomena · Physics 2023-05-25 Sicong Huang , Nico Cappelluti , Massimiliano Galeazzi , Anjali Gupta , Wenhao Liu , Eugenio Ursino , Tomykkutty J. Velliyedathu

The origin of the X-ray emission from the central region of the Galaxy has remained a mystery, despite extensive study over the past two decades. A fundamental question is the relative contribution of the point-source and diffuse components…

Astrophysics · Physics 2007-05-23 Q. D. Wang , E. V. Gotthelf , C. C. Lang

We calculate the flux of radio, hard X-ray and UV radiation from clusters of galaxies as produced by synchrotron emission and Inverse Compton Scattering of electrons generated as secondaries in cosmic ray interactions in the intracluster…

Astrophysics · Physics 2011-08-09 P. Blasi , S. Colafrancesco

The gamma-ray background is still a subject under great debate. All phenomena in the universe emitting gamma-rays can contribute directly as diffuse emission or as an isotropic component from unresolved point sources. The question of the…

Astrophysics · Physics 2007-11-29 Tanja M. Kneiske

Interstellar synchrotron emission depends on Galactic magnetic fields and on cosmic-ray leptons. Observations of radio emission are an important tool for studying cosmic-ray propagation models and interstellar electron spectrum and…

Astrophysics of Galaxies · Physics 2013-07-24 Elena Orlando , Andrew W. Strong

IceCube collaboration reported the first high-significance observation of the neutrino emission from the Galactic disk. The observed signal can be due to diffuse emission produced by cosmic rays interacting with interstellar gas but can…

High Energy Astrophysical Phenomena · Physics 2023-10-25 Vittoria Vecchiotti , Francesco L. Villante , Giulia Pagliaroli