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We present a two-parameter model of the extragalactic gamma-ray background (EGB) in the 0.1-100 GeV range as measured by the Large Area Telescope (LAT) onboard the Fermi satellite. The EGB can be fully explained as the sum of three distinct…

Cosmology and Nongalactic Astrophysics · Physics 2011-05-25 Massimo Cavadini , Ruben Salvaterra , Francesco Haardt

We present the basic features and preliminary results of the interface between our spectro-photometric model GRASIL (that calculates galactic SED from the UV to the sub-mm with a detailed computation of dust extinction and thermal…

Astrophysics · Physics 2007-05-23 L. Silva , G. L. Granato , A. Bressan , C. G. Lacey , C. M. Baugh , S. Cole , C. S. Frenk

TeV gamma rays emitted by GRBs are converted into electron-positron pairs via interactions with the extragalactic infrared radiation fields. In turn the pairs produced, whose trajectories are randomized by magnetic fields, will inverse…

Astrophysics · Physics 2011-04-11 S. Casanova , B. L. Dingus , Bing Zhang

Starlight in the Universe impedes the passage of high energy (e.g. TeV) gamma rays due to positron-electron pair production. The history of this stellar radiation field depends upon observations of star formation rate which themselves can…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Malcolm Fairbairn

We consider the ensemble of very-high-energy gamma-ray sources observed at distances and energies where a significant absorption of gamma rays is expected due to pair production on the extragalactic background light (EBL). Previous studies…

High Energy Astrophysical Phenomena · Physics 2019-12-04 Alexander Korochkin , Grigory Rubtsov , Sergey Troitsky

The first measurements from the CIBER experiment of extragalactic background light (EBL) in near-infrared (NIR) band exhibit a higher intensity than those inferred through $\gamma$-ray observations. Recent theoretical-EBL intensities are…

High Energy Astrophysical Phenomena · Physics 2021-07-21 G. B. Long , W. P. Lin , P. H. T. Tam , W. S. Zhu

Energy spectra of gamma-ray blazars may contain an imprint from the cosmic infrared background radiation due to gamma-ray absorption (pair-production) by soft photons constituting the extragalactic background light (EBL). The signature of…

Astrophysics · Physics 2009-09-29 F. Krennrich , E. Dwek

I present the results of a new approach to the intensity and photon density spectrum of the intergalactic background light as a function of redshift using observational data obtained in many different wavelength bands from local to deep…

High Energy Astrophysical Phenomena · Physics 2013-02-11 Floyd W. Stecker

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

If dark matter is unstable and the mass is within GeV-TeV regime, its decays produce high-energy photons that give contribution to the extragalactic gamma-ray background (EGRB). We constrain dark matter decay by analyzing the 50-month EGRB…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Shin'ichiro Ando , Koji Ishiwata

The very high energy (VHE) $\gamma$-ray spectra of some TeV Blazars, after being corrected for absorption in the extragalactic background light (EBL), appear unusually hard, which poses challenges to conventional acceleration and emission…

High Energy Astrophysical Phenomena · Physics 2015-05-28 E. Lefa , F. M. Rieger , F. Aharonian

Observations of distant sources of high-energy (HE) gamma-rays are affected by attenuation resulting from the interaction of the gamma-rays with low energy photons from the diffuse meta-galactic radiation fields at ultraviolet (UV) to…

Cosmology and Nongalactic Astrophysics · Physics 2011-08-12 Martin Raue

Very high energy photons from cosmological gamma-ray bursts (GRBs) are expected to interact with extragalactic background light (EBL) and produce electron-positron pairs when they propagate through intergalactic medium (IGM). These…

High Energy Astrophysical Phenomena · Physics 2020-04-08 Ze-Rui Wang , Shao-Qiang Xi , Ruo-Yu Liu , Rui Xue , Xiang-Yu Wang

Deep optical and near-infrared galaxy counts are utilized to estimate the extragalactic background light (EBL) coming from normal galactic light in the universe. Although the slope of number-magnitude relation of the faintest counts is flat…

Astrophysics · Physics 2009-11-06 T. Totani , Y. Yoshii , F. Iwamuro , T. Maihara , K. Motohara

Despite the influx of unprecedented-quality data from the Fermi Gamma-Ray Space Telescope that have been collected over nine years of operation, the contribution of normal star-forming galaxies to the extragalactic gamma-ray background…

High Energy Astrophysical Phenomena · Physics 2018-12-19 I. Komis , V. Pavlidou , A. Zezas

The Extragalactic Background Light (EBL) at UV, optical and NIR wavelengths consists of the integrated light of all unresolved galaxies along the line of sight plus any contributions by intergalactic matter including hypothetical decaying…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Kalevi Mattila , Kimmo Lehtinen , Petri Vaisanen , Gerhard von Appen-Schnur , Christoph Leinert

The high redshift observations of galaxies now becoming available from the Hubble Space Telescope and from large ground based telescopes are opening fresh windows on galaxy formation. Semianalytic models of galaxy formation provide us with…

Astrophysics · Physics 2007-05-23 C. M. Baugh , C. G. Lacey , S. Cole , C. S. Frenk

Several models which have been constructed to explain the faint galaxy excess in observed number counts are used to predict the intensity of the extragalactic background light (EBL). Special attention is given to irregular and dwarf…

Astrophysics · Physics 2007-05-23 Petri Vaisanen

The optical/far-IR extragalactic background light (EBL) from both resolved and unresolved extragalactic sources is an indicator of the total luminosity of cosmic structures, as the cumulative emission from young and evolved galactic…

Astrophysics · Physics 2007-05-23 Piero Madau , Francesco Haardt , Lucia Pozzetti