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The propagation of very-high-energy gamma-rays (VHEGRs) in the extragalactic space offers the opportunity to study astrophysical phenomena not reproducible in laboratories. In particular, the deviation from predictions of the observed…

High Energy Astrophysical Phenomena · Physics 2024-05-27 Luis Enrique Espinosa Castro , Simone Rossoni , Günter Sigl

We present the newest statistical and numerical analysis of the matter and cosmic microwave background power spectrum with effects of the primordial magnetic field (PMF) included. New limits to the PMF strength and power spectral index are…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-06 Dai G. Yamazaki , Kiyotomo Ichiki , Toshitaka Kajino , Grant. J. Mathews

The main aim of this paper is to provide cosmological constraints on the Multi Scalar Field Dark Matter model (MSFDM), in which we assume the dark matter is made up of different ultra-light scalar fields. As a first approximation, we…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-05 L. O. Téllez-Tovar , Tonatiuh Matos , J. Alberto Vázquez

A new estimation of the isotropic diffuse gamma-ray background (IGRB) observed by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope (Fermi) has been presented for 50 months of data, in the energy range 100 MeV-820…

High Energy Astrophysical Phenomena · Physics 2017-05-17 Mattia Di Mauro , Fiorenza Donato

Relativistic pair beams produced in the intergalactic medium (IGM) by TeV gamma rays from blazars are expected to generate a detectable GeV-scale electromagnetic cascade, yet this cascade is absent in the observed spectra of hard-spectrum…

High Energy Astrophysical Phenomena · Physics 2024-12-03 Mahmoud Alawashra , Ievgen Vovk , Martin Pohl

Structure formation in the intergalactic medium (IGM) produces large-scale, collisionless shock waves, where electrons can accelerate to highly relativistic energies. Such electrons can Compton scatter cosmic microwave background photons up…

Astrophysics · Physics 2009-11-07 Uri Keshet , Eli Waxman , Abraham Loeb , Volker Springel , Lars Hernquist

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

We construct a map of deflections of ultra-high energy cosmic rays by extragalactic magnetic fields using a magneto-hydrodynamical simulation of cosmic structure formation that realistically reproduces the positions of known galaxy clusters…

Astrophysics · Physics 2009-11-10 Klaus Dolag , Dario Grasso , Volker Springel , Igor Tkachev

The origin of astrophysical magnetic fields observed in galaxies and clusters of galaxies is still unclear. One possibility is that primordial magnetic fields generated in the early Universe provide seeds that grow through compression and…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 C. Fedeli , L. Moscardini

The universe is filled with a diffuse and isotropic extragalactic background of gamma-ray radiation, containing roughly equal energy flux per decade in photon energy between 3 MeV-100 GeV. The origin of this background is one of the…

Astrophysics · Physics 2011-05-05 Abraham Loeb , Eli Waxman

(Abridged) We present a new model of the blazar gamma-ray luminosity function (GLF) and the spectrum of the extragalactic gamma-ray background (EGRB), which is consistent with the observed distributions of EGRET blazars. The unified…

Astrophysics · Physics 2011-01-27 Yoshiyuki Inoue , Tomonori Totani

We conduct a series of magnetohydrodynamical (MHD) simulations of magnetized interstellar medium (ISM) disturbed by exploding stars. Each star deposits a randomly oriented, dipolar magnetic field into ISM. The simulations are performed in a…

Astrophysics · Physics 2011-11-10 K. Kowalik , M. Hanasz

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

The origin of interstellar and intergalactic magnetic fields remains largely unknown. One possibility is that they are related to the primordial magnetic fields (PMFs) produced by, for instance, the phase transitions of the early Universe.…

High Energy Astrophysical Phenomena · Physics 2024-03-05 Yao-Yu Li , Chi Zhang , Ziwei Wang , Ming-Yang Cui , Yue-Lin Sming Tsai , Qiang Yuan , Yi-Zhong Fan

In this work we consider an extended electromagnetic theory in which the scalar state which is usually eliminated by means of the Lorenz condition is allowed to propagate. This state has been shown to generate a small cosmological constant…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-01 Jose Beltran Jimenez , Antonio L. Maroto

Data from (non-) attenuation of gamma rays from active galactic nuclei (AGN) and gamma ray bursts (GRBs) give upper limits on the extragalactic background light (EBL) from the UV to the mid-IR that are only a little above the lower limits…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Joel R. Primack , Alberto Dominguez , Rudy C. Gilmore , Rachel S. Somerville

We constrain a stochastic background of primordial magnetic fields (PMF) by its contribution to the cosmic microwave background (CMB) anisotropy angular power spectrum with the combination of WMAP 7 year and South Pole Telescope (SPT) data.…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-23 Daniela Paoletti , Fabio Finelli

A generation of magnetic fields from cosmological density perturbations is investigated. In the primordial plasma before cosmological recombination, all of the materials except dark matter in the universe exist in the form of photons,…

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

The effects of magnetic fields on Big Bang Nucleosynthesis(BBN) have been calculated, and the impact on the abundances of the light elements have been investigated numerically. An upper limit on the strength of primordial magnetic fields…

Astrophysics · Physics 2009-12-30 Baolian Cheng , David N. Schramm , James W. Truran