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The intensity of the soft X-Ray background is correlated with the distribution of galaxies. To demonstrate this, magnitude limited galaxy samples extracted from bright galaxy catalogues and the Lick counts are utilized. Significant…

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

We analyze Chandra observations of diffuse soft X-ray emission associated with a complete sample of 3CR radio galaxies at z < 0.3. In this paper we focus on the properties of the spectroscopic sub-classes of high excitation galaxies (HEGs)…

FERMI (formely GLAST) will shortly provide crucial information on relativistic particles in galaxy clusters. We discuss non-thermal emission in the context of general calculations in which relativistic particles (protons and secondary…

Astrophysics · Physics 2009-02-19 G. Brunetti , P. Blasi , R. Cassano , S. Gabici

We show that the complex shape of the cosmic ray (CR) spectrum, as recently measured by PAMELA and inferred from Fermi-LAT gamma-ray observations of molecular clouds in the Gould belt, can be naturally understood in terms of basic plasma…

High Energy Astrophysical Phenomena · Physics 2012-08-10 Pasquale Blasi , Elena Amato , Pasquale D. Serpico

Star formation in galaxies is observed to be associated with gamma-ray emission. The detection of gamma rays from star-forming galaxies by the Fermi Large Area Telescope (LAT) has allowed the determination of a functional relationship…

High Energy Astrophysical Phenomena · Physics 2012-08-07 Emma Storm , Tesla E. Jeltema , Stefano Profumo

A spherical-symmetric gamma-ray emission from the central region of the Galaxy has been recently identified in Fermi-LAT data, and initially associated to dark matter particle annihilations. Guided by the evidence for a high gas density in…

High Energy Astrophysical Phenomena · Physics 2016-01-13 Daniele Gaggero , Marco Taoso , Alfredo Urbano , Mauro Valli , Piero Ullio

The Fermi Gamma-ray Space Telescope has revealed a diffuse $\gamma$-ray background at energies from 0.1 GeV to 1 TeV, which can be separated into Galactic emission and an isotropic, extragalactic component. Previous efforts to understand…

High Energy Astrophysical Phenomena · Physics 2021-09-17 Matt A. Roth , Mark R. Krumholz , Roland M. Crocker , Silvia Celli

The spectrum of the diffuse isotropic component of cosmic X-rays over the 13-180 keV range was determined by the UCSD/MIT Hard X-Ray and Gamma-Ray instrument (HEAO A4) on the High Energy Astronomical Observatory-1 (HEAO-1). The instrument…

Astrophysics · Physics 2009-10-31 D. E. Gruber , J. L. Matteson , L. E. Peterson , G. V. Jung

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

We present Chandra/ACIS images of several high-mass star-forming regions. The massive stellar clusters powering these HII regions are resolved at the arcsecond level into hundreds of stellar sources, similar to those seen in closer young…

Astrophysics · Physics 2007-05-23 L. Townsley , E. Feigelson , T. Montmerle , P. Broos , Y. -H. Chu , G. Garmire , K. Getman

Interactions of cosmic rays with the interstellar gas and radiation fields of the Milky Way provide the majority of the gamma rays observed by the Fermi Gamma Ray Space Telescope. In addition to the gas which is densely concentrated along…

High Energy Astrophysical Phenomena · Physics 2015-06-05 Robert Feldmann , Dan Hooper , Nickolay Y. Gnedin

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

The angular resolution (~10") achieved by the Herschel Space Observatory ~3.5m telescope at FIR wavelengths allowed us to roughly separate the emission toward the inner parsec of the galaxy (the central cavity) from that of the surrounding…

Astrophysics of Galaxies · Physics 2017-02-22 J. R. Goicoechea , M. Etxaluze , J. Cernicharo , M. Gerin , J. Pety

We reported the gamma-ray observation towards the giant molecular cloud Polaris Flare. Together with the dust column density map, we derived the cosmic ray density and spectrum in this cloud. Compared with the CR measured locally, the CR…

High Energy Astrophysical Phenomena · Physics 2021-12-08 Zhi-wei Cui , Rui-zhi Yang , Bing Liu

Most of the celestial gamma rays detected by the Large Area Telescope (LAT) aboard the Fermi Gamma-ray Space Telescope originate from the interstellar medium when energetic cosmic rays interact with interstellar nucleons and photons.…

High Energy Astrophysical Phenomena · Physics 2016-04-27 F. Acero , M. Ackermann , M. Ajello , A. Albert , L. Baldini , J. Ballet , G. Barbiellini , D. Bastieri , R. Bellazzini , E. Bissaldi , E. D. Bloom , R. Bonino , E. Bottacini , T. J. Brandt , J. Bregeon , P. Bruel , R. Buehler , S. Buson , G. A. Caliandro , R. A. Cameron , M. Caragiulo , P. A. Caraveo , J. M. Casandjian , 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 , R. Desiante , S. W. Digel , L. Di Venere , P. S. Drell , C. Favuzzi , S. J. Fegan , E. C. Ferrara , W. B. Focke , A. Franckowiak , S. Funk , P. Fusco , F. Gargano , D. Gasparrini , N. Giglietto , F. Giordano , M. Giroletti , T. Glanzman , G. Godfrey , I. A. Grenier , S. Guiriec , D. Hadasch , A. K. Harding , K. Hayashi , E. Hays , J. W. Hewitt , A. B. Hill , D. Horan , X. Hou , T. Jogler , G. Jóhannesson , T. Kamae , M. Kuss , D. Landriu , S. Larsson , L. Latronico , J. Li , L. Li , F. Longo , F. Loparco , M. N. Lovellette , P. Lubrano , S. Maldera , D. Malyshev , A. Manfreda , P. Martin , M. Mayer , M. N. Mazziotta , J. E. McEnery , P. F. Michelson , N. Mirabal , T. Mizuno , M. E. Monzani , A. Morselli , E. Nuss , T. Ohsugi , N. Omodei , M. Orienti , E. Orlando , J. F. Ormes , D. Paneque , M. Pesce-Rollins , F. Piron , G. Pivato , S. Rainò , R. Rando , M. Razzano , S. Razzaque , A. Reimer , O. Reimer , Q. Remy , N. Renault , M. Sánchez-Conde , M. Schaal , A. Schulz , C. Sgrò , E. J. Siskind , F. Spada , G. Spandre , P. Spinelli , A. W. Strong , D. J. Suson , H. Tajima , H. Takahashi , J. B. Thayer , D. J. Thompson , L. Tibaldo , M. Tinivella , D. F. Torres , G. Tosti , E. Troja , G. Vianello , M. Werner , K. S. Wood , M. Wood , G. Zaharijas , S. Zimmer

In this contribution we will discuss recent results concerning the intensity and the angular distribution of the gamma-ray and neutrino emissions as should be originated from the hadronic scattering of cosmic rays (CR) with the interstellar…

Astrophysics · Physics 2007-08-02 C. Evoli , D. Grasso , L. Maccione

Using the Chandra Advanced CCD Imaging Spectrometer Imaging array (ACIS-I), we have carried out a deep hard X-ray observation of the Galactic plane region at (l,b) ~ (28.5, 0.0), where no discrete X-ray source had been reported previously.…

A number of radio galaxies has been detected by Fermi/LAT in the gamma-ray domain. In some cases, like Cen A and M 87, these objects have been seen even in the TeV range by Cherenkov telescopes. Whereas the gamma-ray emission is likely to…

High Energy Astrophysical Phenomena · Physics 2013-02-20 V. Beckmann , S. de Jong , F. Mattana , D. Saez , S. Soldi

Recent results from the HESS gamma ray telescope have shown the presence of both a diffuse, extended, flux of gamma rays above ~0.4 TeV and discrete sources in and near the Galactic Centre. Here, we put forward a possible explanation in…

Astrophysics · Physics 2009-06-23 A. D. Erlykin , A. W. Wolfendale