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(Abridged) We constrain simulated all-sky maps in total intensity, linear polarization, and rotation measure (RM) by observations. We test a number of large-scale magnetic field configurations and take the properties of the warm…

Astrophysics · Physics 2009-11-13 X. H. Sun , W. Reich , A. Waelkens , T. Enßlin

In a recently proposed model the cosmic rays spectrum at energies above 10^{18} eV can be fitted with a minimal number of unknown parameters assuming that the extragalactic cosmic rays are only protons with a power law source spectrum…

Astrophysics · Physics 2008-11-26 Graciela Gelmini , Oleg Kalashev , Dmitry V. Semikoz

The Extragalactic Background Light (EBL) is the accumulated light emitted throughout the history of the universe, spanning the UV, optical, and IR spectral ranges. Stars and dust in galaxies are expected to be the main source of the EBL.…

High Energy Astrophysical Phenomena · Physics 2025-12-03 R. Grau , A. Moralejo

Intermediate Mass Black Holes (IMBHs; 10^1.3-5 M_sun) are thought to form as relics of Population III stars or from the runaway collapse of stars in young clusters; their number and very existence are uncertain. We ran N-body simulations of…

Astrophysics · Physics 2009-11-11 M. Mapelli , A. Ferrara , N. Rea

We investigate the generation of magnetic field by the Biermann battery in cosmological ionization fronts, using new simulations of the reionization of the universe by stars in protogalaxies. Two mechanisms are primarily responsible for…

Astrophysics · Physics 2009-10-31 Nickolay Y. Gnedin , Andrea Ferrara , Ellen G. Zweibel

The large-scale magnetic fields we observe today in galaxies and galaxy clusters could be the result of a pure quantum effect taking place during inflation, to wit, the creation of particles (photons) out from the vacuum in a curved…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-26 Leonardo Campanelli

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

Mapping the intergalactic medium (IGM) in Lyman-$\alpha$ emission would yield unprecedented tomographic information on the large-scale distribution of baryons and potentially provide new constraints on the UV background and various feedback…

Astrophysics of Galaxies · Physics 2021-06-22 Joris Witstok , Ewald Puchwein , Girish Kulkarni , Renske Smit , Martin G. Haehnelt

Star formation rates (SFR) larger than 1000 Msun/ yr are observed in extreme star bursts. This leads to the formation of star clusters with masses > 10^6 Msun in which crowding of the pre-stellar cores may lead to a change of the stellar…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Carsten Weidner , Pavel Kroupa , Jan Pflamm-Altenburg

Prompt emissions from TeV blazars pair produce off the extragalactic background light and the highly energetic resulting pair beams then cascade through inverse Compton scattering to give rise to secondary gamma-rays. Such reprocessed…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-02 Oindrila Ghosh , Sankalan Bhattacharyya

The cosmological magnetic field is one of the important physical quantities which affect strongly the cosmic microwave background (CMB) power spectrum. Recent CMB observations have been extended to higher multipoles $l\gtrsim$1000, and they…

Astrophysics · Physics 2009-11-10 D. G. Yamazaki , K. Ichiki , T. Kajino

In this work, we analyze the implications of graviton to photon conversion in the presence of large scale magnetic fields. We consider the magnetic fields associated with galaxy clusters, filaments in the large scale structure, as well as…

General Relativity and Quantum Cosmology · Physics 2009-10-29 M. S. Pshirkov , D. Baskaran

Recent FERMI observations provide a lower limit of 10^{-15} G for the magnetic field strength in the intergalactic medium (IGM). This is consistent with theoretical expectations based on the Biermann battery effect, which predicts such IGM…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-18 Dominik R. G. Schleicher , Sharanya Sur , Robi Banerjee , Ralf S. Klessen , Christoph Federrath , Tigran Arshakian , Rainer Beck , Marco Spaans

We consider the synchrotron emission from electrons out in the Galactic halo bubble region where the Fermi bubble structures reside. Utilising a simple analytical expression for the non-thermal electron distribution and a toy magnetic field…

High Energy Astrophysical Phenomena · Physics 2022-10-04 Vasundhara Shaw , Arjen van Vliet , Andrew M. Taylor

Very-high-energy gamma rays produce electron positron pairs in interactions with low-energy photons of extragalactic background light during propagation through the intergalactic medium. The electron-positron pairs generate secondary gamma…

High Energy Astrophysical Phenomena · Physics 2023-07-12 O. Kalashev , A. Korochkin , A. Neronov , D. Semikoz

Intergalactic magnetic fields in the voids of the large-scale structure can be probed via measurements of secondary gamma-ray emission from gamma-ray interactions with extragalactic background light. Lower bounds on the magnetic field in…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-20 Kyrylo Bondarenko , Alexey Boyarsky , Alexander Korochkin , Andrii Neronov , Dmitri Semikoz , Anastasia Sokolenko

The extragalactic background light (EBL) from the infrared to the ultraviolet is difficult to measure directly, but can be constrained with a variety of methods. EBL photons absorb gamma-rays from distant blazars, allowing one to use blazar…

High Energy Astrophysical Phenomena · Physics 2014-11-18 Justin D. Finke , Soebur Razzaque

The direct measurement of the extragalactic background light (EBL) is difficult at optical to infrared wavelengths because of the strong foreground radiation originating in the Solar System. Very high energy (VHE, E$>$100 GeV) gamma rays…

Astrophysics · Physics 2009-09-29 M. Schroedter

We use a set of Monte Carlo simulations to follow the cascade produced by a primary electron of energy E_in in the intergalactic medium. We choose E_in=3-10 keV as expected from the decay of one of the most popular Warm Dark Matter (WDM)…

Astrophysics · Physics 2009-11-13 M. Valdés , A. Ferrara

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
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