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Related papers: A new model for the extragalactic gamma-ray backgr…

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The spectral shape of the unresolved emission from different classes of gamma-ray emitters can be used to disentangle the contributions from these populations to the extragalactic gamma-ray background (EGRB). We present a calculation of the…

Astrophysics · Physics 2010-11-11 Vasiliki Pavlidou , Tonia M. Venters

We present the results of a new model calculation of the gamma-ray background produced by unresolved blazars, using the second EGRET catalogue and taking account of flaring. These results are compared to the preliminary gamma-ray background…

Astrophysics · Physics 2009-10-28 F. W. Stecker , M. H. Salamon

We use the recent measurement of the isotropic $\gamma$-ray background (IGRB) by Fermi LAT and analysis of the contribution of unresolved point $\gamma$-ray sources to IGRB to build constraints on the models of ultra-high cosmic rays…

High Energy Astrophysical Phenomena · Physics 2016-11-23 Oleg Kalashev

Using a significantly enlarged \textit{Fermi}-LAT BL Lac objects (BL Lacs) sample, we construct the gamma-ray luminosity function (GLF) of BL Lacs, by the joint use of the space density distribution and source counts distribution. We use…

High Energy Astrophysical Phenomena · Physics 2019-10-02 Yankun Qu , Houdun Zeng , Dahai Yan

The extragalactic background light (EBL) is of fundamental importance both for understanding the entire process of galaxy evolution and for gamma-ray astronomy. However, the overall spectrum of the EBL between 0.1 and 1000 microns has never…

Direct measurements of the extragalactic background light (EBL) in the near-IR to mid-IR waveband are extremely difficult due to an overwhelming foreground from the zodiacal light that outshines the faint cosmological diffuse radiation…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Matthew Orr , Frank Krennrich , Eli Dwek

The Extragalactic Background Light (EBL) is the integrated light from all the stars that have ever formed, and spans the IR-UV range. The interaction of very-high-energy (VHE: E>100 GeV) gamma-rays, emitted by sources located at…

Cosmology and Nongalactic Astrophysics · Physics 2010-01-04 Massimo Persic , Nijil Mankuzhiyil , Fabrizio Tavecchio

The extragalactic background light (EBL) in the IR to UV bands partly absorbs very high energy (VHE, $E \geq$ 100GeV) $\gamma-$ray photons travelling over cosmological distances via pair production. In this paper, to get stronger…

High Energy Astrophysical Phenomena · Physics 2023-03-01 Longhua Qin , Jiancheng Wang , Quangui Gao , Weiwei Na , Huaizhen Li , Ao Wang , Chuyuan Yang , Jianping Yang

A strict lower limit flux for the extragalactic background light from ultraviolet to the far-infrared photon energies is presented. The spectral energy distribution is derived using an established EBL model based on galaxy formation. The…

Astrophysics · Physics 2009-11-13 Tanja M. Kneiske , Herve Dole

The Fermi Large Area Telescope (LAT) Collaboration has recently released a catalog of 360 sources detected above 50 GeV (2FHL). This catalog was obtained using 80 months of data re-processed with Pass 8, the newest event-level analysis,…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-20 LAT Collaboration

Building on our previous cross-correlation analysis (Xia et al. 2011) between the isotropic gamma-ray background (IGRB) and different tracers of the large-scale structure of the universe, we update our results using 60-months of data from…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-24 Jun-Qing Xia , Alessandro Cuoco , Enzo Branchini , Matteo Viel

Motivated by the idea that the recently detected near-infrared (1.2-4 micron) excess over the contribution of known galaxies is due to redshifted light from the first cosmic stars (Salvaterra & Ferrara 2003), we have used the effect caused…

Astrophysics · Physics 2008-11-26 M. Mapelli , R. Salvaterra , A. Ferrara

Recent radio surveys have discovered a large number of low luminosity core dominated radio galaxies that are much more abundant than those at higher luminosities. These objects will be too faint in gamma-rays to be detected individually by…

Astrophysics of Galaxies · Physics 2019-07-17 Floyd W. Stecker , Chris R. Shrader , Matthew. A. Malkan

We briefly review contemporary extragalactic {\gamma}-ray propagation models. It is shown that the Extragalactic Magnetic Field (EGMF) strength and structure are poorly known. Strict lower limits on the EGMF strength in voids are of order…

High Energy Astrophysical Phenomena · Physics 2017-04-05 T. A. Dzhatdoev , E. V. Khalikov , A. P. Kircheva , A. A. Lyukshin

One way to understand the nonthermal history of the universe is by establishing the origins of the unresolved and truly diffuse extragalactic gamma rays. Dim blazars and radio/gamma galaxies certainly make an important contribution to the…

Astrophysics · Physics 2009-06-23 Charles D. Dermer

We present a revised measurement of the extra-galactic background light (EBL) at radio frequencies based on a near complete compendium of radio source counts. We present the radio-EBL at 150 MHz, 325 MHz, 610 MHz, 1.4 GHz, 3 GHz, 5 GHz, and…

The origin of the extragalactic gamma-ray background is a pressing cosmological mystery. The Fermi Gamma-Ray Space Telescope has recently measured the intensity and spectrum of this background; both are substantially different from previous…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-16 Brian D. Fields , Vasiliki Pavlidou , Tijana Prodanovic

The study of the Extragalactic Background Light (EBL) is crucial to understand many astrophysical problems (as the formation of first stars, the evolution of galaxies and the role of dust emission). At present, one of the most powerful ways…

Astrophysics · Physics 2007-05-23 M. Mapelli , R. Salvaterra , A. Ferrara

The diffuse extragalactic background light consists of the sum of the starlight emitted by galaxies through the history of the Universe, and it could also have an important contribution from the first stars, which may have formed before…

Astrophysics · Physics 2012-08-27 H. E. S. S. Collaboration , : , F. Aharonian

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