English
Related papers

Related papers: Extragalactic Very-High-Energy gamma-ray backgroun…

200 papers

In this work, we use two different methods to determine the opacity of the TeV gamma-rays caused by the extragalactic background light (EBL) via e-e+ production due to photon-photon interaction. The first method, Model-Dependent Approach,…

High Energy Astrophysical Phenomena · Physics 2020-04-07 K. K. Singh , P. J. Meintjes

High-energy photons from cosmological emitters suffer attenuation due to pair production interactions with the extragalactic background light (EBL). The collective emission of any high-energy emitting cosmological population will exhibit an…

High Energy Astrophysical Phenomena · Physics 2014-11-20 Tonia M. Venters , Vasiliki Pavlidou , Luis C. Reyes

The attenuation produced by extragalactic background light (EBL) in $\gamma$-ray spectra of blazars has been used to constrain the Hubble constant ($H_0$) and matter density ($\Omega_{\rm m}$) of the Universe. We propose to estimate $H_0$…

High Energy Astrophysical Phenomena · Physics 2019-09-11 Houdun Zeng , Dahai Yan

In addition to its relevant astrophysical and cosmological significance, the Extragalactic Background Light (EBL) is a fundamental source of opacity for cosmic high energy photons, as well as a limitation for the propagation of high-energy…

High Energy Astrophysical Phenomena · Physics 2017-07-05 Alberto Franceschini , Giulia Rodighiero

VHE (Very High Energy, E>100 GeV) radiation emitted at cosmological distances will pair produce on low-energy diffuse extragalactic background radiation before ever reaching us. This prevents us from directly seeing most of the VHE emission…

Astrophysics · Physics 2009-10-28 P. S. Coppi , F. A. Aharonian

Context. Measurements of the Extragalactic Background Light (EBL) are a fundamental source of information on the collective emission of cosmic sources. Aims. At infrared wavelengths, however, these measurements are precluded by the…

High Energy Astrophysical Phenomena · Physics 2019-08-28 A. Franceschini , L. Foffano , E. Prandini , F. Tavecchio

Several classes of astrophysical sources contribute to the approximately isotropic gamma-ray background measured by the Fermi Gamma-Ray Space Telescope. In this paper, we use Fermi's catalog of gamma-ray sources (along with corresponding…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Ilias Cholis , Dan Hooper , Samuel D. McDermott

Motivated by the discovery of the ultra-strong emission line starburst galaxies (EELGs) known as "green pea galaxies", we consider here their contribution to the intergalactic flux of ionizing UV at high redshifts. Most galaxies that have…

Astrophysics of Galaxies · Physics 2021-08-19 Matthew A. Malkan , Sean T. Scully , Floyd W. Stecker

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…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Alberto Domínguez

The origin of the extragalactic gamma-ray background radiation at 1-10 MeV is still unknown. Although the cosmic X-ray background (CXB) up to a few hundreds keV can be accounted for by the sum of Active Galactic Nuclei (AGNs), current…

Astrophysics · Physics 2009-11-13 Yoshiyuki Inoue , Tomonori Totani , Yoshihiro Ueda

The intrinsic BL Lac spectra above few hundreds GeV can be very different from the observed ones due to the absorption effects by the diffuse Extragalactic Background Light (EBL), at present poorly known. With the recent results, there are…

Astrophysics · Physics 2009-11-10 L. Costamante , F. Aharonian , D. Horns , G. Ghisellini

We re-derive the possible dependence of the redshift with very high energy (VHE) $\gamma$-ray photon index. The results suggest that the universe to VHE $\gamma$-rays is becoming more transparent than usually expected. We introduce the…

High Energy Astrophysical Phenomena · Physics 2023-08-02 L. J. Dong , Y. G. Zheng , S. J. Kang

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…

Ground-based observatories have been collecting 0.2 - 20 TeV gamma rays from blazars for about twenty years. These gamma rays can experience absorption along the line of sight due to interactions with the extragalactic background light…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-14 Jonathan Biteau , David A. Williams

The extragalactic background light (EBL) is the cumulative radiation outside the Milky Way. The determination of its corresponding primary emitting sources as well as its total energy level across the entire electromagnetic spectrum has…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-27 Qi-Ning Hsu , L. L. Cowie , Chian-Chou Chen , A. J. Barger

The light emitted by all galaxies over the history of the Universe produces the extragalactic background light (EBL) at ultraviolet, optical, and infrared wavelengths. The EBL is a source of opacity for $\gamma$ rays via photon-photon…

High Energy Astrophysical Phenomena · Physics 2018-12-05 LAT Collaboration , M. Ajello , K. Helgason , V. Paliya , J. Finke , A. Dominguez , A. Desai

Combining the results of targeted observations, H.E.S.S. has accumulated a large amount of extra-galactic exposure at TeV energies. Due to its large field of view a considerable part of the sky (0.6 sr) has been observed with high…

Astrophysics · Physics 2019-08-14 T. Herr , W. Hofmann

The development of techniques whereby gamma rays of energy 100 GeV and above can be studied from the ground, using indirect, but sensitive, techniques has opened up a new area of high energy photon astronomy. The most exciting result that…

Astrophysics · Physics 2009-11-10 D. Horan , T. C. Weekes

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

It has been suggested that unresolved radio galaxies and radio quasars (sometimes referred to as misaligned active galactic nuclei) could be responsible for a significant fraction of the observed diffuse gamma-ray background. In this study,…

High Energy Astrophysical Phenomena · Physics 2016-08-17 Dan Hooper , Tim Linden , Alejandro Lopez