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We present predictions for the UV-to-mm extragalactic background light (EBL) from a recent version of the GALFORM semi-analytical model of galaxy formation which invokes a top-heavy stellar initial mass function (IMF) for galaxies…

Astrophysics of Galaxies · Physics 2019-06-19 William. I. Cowley , Cedric G. Lacey , Carlton M. Baugh , Shaun Cole , Carlos S. Frenk , Claudia del P. Lagos

The recent HEGRA observations of the blazar Mkn 501 show strong curvature in the very high energy gamma-ray spectrum. Applying the gamma-ray opacity derived from an empirically based model of the intergalactic infrared background radiation…

We present new synthesis models of the extragalactic background light (EBL) from far infra-red (FIR) to TeV gamma-rays, with an emphasis on the extreme ultraviolet (UV) background which is responsible for the observed ionization and thermal…

Astrophysics of Galaxies · Physics 2019-02-20 Vikram Khaire , Raghunathan Srianand

We present two models for the cosmological UV background light, and calculate the opacity of GeV gamma--rays out to redshift 9. The contributors to the background include 2 possible quasar emissivities, and output from star--forming…

Astrophysics · Physics 2009-11-13 Rudy C. Gilmore , Piero Madau , Joel R. Primack , Rachel S. Somerville

The diffuse meta-galactic radiation field at ultraviolet to infrared wavelengths - commonly labeled extragalactic background light (EBL) - contains the integrated emission history of the universe. Difficult to access via direct…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-02 Martin Raue , Daniel Mazin

We present models of the extragalactic background light (EBL) based on several scenarios of galaxy formation and evolution. We have treated galaxy formation with the Press-Schecter approximation for both cold dark matter (CDM) and cold+hot…

Astrophysics · Physics 2008-02-03 Donn MacMinn , Joel R. Primack

We present models of the extragalactic background light (EBL) based on several scenarios of galaxy formation and evolution. We have treated galaxy formation with the Press-Schecter approximation for both cold dark matter (CDM) and cold+hot…

Astrophysics · Physics 2009-12-10 D. MacMinn , J. R. Primack

The Fermi gamma-ray space telescope has revolutionized our understanding of the cosmic gamma-ray background radiation in the GeV band. However, investigation on the cosmic TeV gamma-ray background radiation still remains sparse. Here, we…

High Energy Astrophysical Phenomena · Physics 2016-03-09 Yoshiyuki Inoue , Yasuyuki T. Tanaka

Recently, a spatially extended excess of gamma rays collected by the Fermi-LAT from the inner region of the Milky Way has been detected by different groups and with increasingly sophisticated techniques. Yet, any final conclusion about the…

High Energy Astrophysical Phenomena · Physics 2015-02-11 Francesca Calore , Ilias Cholis , Christoph Weniger

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

Using the cosmic ray (CR) data available in the energy interval $(10 - 2 \times 10^{7})$ GeV/particle, we have calculated the profile of the primary $\gamma$-ray spectrum produced by the interaction of these CR with thermal nuclei of the…

Astrophysics · Physics 2009-10-30 G. A. Medina Tanco , E. M. de Gouveia Dal Pino

The Extragalactic Background Light (EBL) can be probed via the absorption imprint it leaves in the spectra of gamma-ray sources ($\gamma\gamma \rightarrow e^-e^+$). We recently developed a dedicated technique to reconstruct the EBL, and its…

High Energy Astrophysical Phenomena · Physics 2019-04-03 Abhishek Desai , Kári Helgason , Marco Ajello , Vaidehi Paliya , Alberto Domínguez , Justin Finke , Dieter H. Hartmann

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

In developing a deeper understanding of the Circumgalactic Medium, one feature that is poorly understood is the nature of the ultraviolet background (UVB) and its impact on observed column densities. A wide array of UVB models have been…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-30 Elias Taira , Claire Kopenhafer , Brian W. O'Shea

The extragalactic background light (EBL), the cumulative radiation from all extragalactic sources, traces galaxy formation and cosmic evolution. High-energy $\gamma$ rays attenuated via pair production with EBL photons are a powerful probe…

High Energy Astrophysical Phenomena · Physics 2026-04-13 J. Baxter , A. Dominguez , J. D. Finke , A. Desai , M. Ajello , A. Banerjee , Dieter Hartmann , Vaidehi S. Paliya

The intensity of the extragalactic background (EBL), the accumulated optical and infrared emissions since the first stars, is the subject of a decades-long tension in the optical band. These photons form a target field that attenuates the…

High Energy Astrophysical Phenomena · Physics 2024-10-10 Lucas Gréaux , Jonathan Biteau , Mireia Nievas Rosillo

The observed spectra of blazars, their intrinsic emission, and the underlying populations of radiating particles are intimately related. The use of these sources as probes of the extragalactic infrared background, a prospect propelled by…

Astrophysics · Physics 2009-11-13 Floyd W. Stecker , Matthew G. Baring , Errol J. Summerlin

To characterise the cosmological evolution of the sources contributing to the infrared extragalactic background, we have developped a phenomenological model that constrains in a simple way the galaxy luminosity function evolution with the…

Astrophysics · Physics 2016-08-30 G. Lagache , H. Dole , J. -L. Puget

A new semi-analytic modelling of galaxy evolution in the IR/submm is hereafter outlined. This type of approach successfully reproduces the optical properties of galaxies. We illustrate a simple extension to the IR/submm wavelength range by…

Astrophysics · Physics 2007-05-23 B. Guiderdoni , E. Hivon , F. R. Bouchet

We provide our estimates of the intensity of the gamma-ray emission with an energy near 0.1 TeV generated in inrergalactic space in the interactions of cosmic rays with background emissions. We assume that the cosmic ray sources are…

High Energy Astrophysical Phenomena · Physics 2017-08-30 A. V. Uryson