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The origin of extragalactic magnetic fields is still poorly understood. Based on a dedicated suite of cosmological magneto-hydrodynamical simulations with the ENZO code we have performed a survey of different models that may have caused…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-22 F. Vazza , M. Brüggen , C. Gheller , S. Hackstein , D. Wittor , P. M. Hinz

Very high energy (VHE, energy $E \gtrsim 100$\,GeV) \gamma-rays from cosmological sources are attenuated due to the interaction with photons of the extragalactic background light (EBL) in the ultraviolet to infrared wavelength band. The…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-05 Manuel Meyer , Martin Raue , Daniel Mazin , Dieter Horns

Magnetic fields are an important component of the interstellar medium (ISM) of galaxies. The thermal gas in the ISM has a multiphase structure, broadly divided into ionised, atomic, and molecular phases. The connection between the…

Astrophysics of Galaxies · Physics 2025-04-01 Amit Seta , N. M. McClure-Griffiths

The intracluster medium (ICM) is the low-density diffuse magnetized plasma in galaxy clusters, which reaches virial temperatures of up to 10^8 K. Under these conditions, the plasma is weakly collisional and therefore has an anisotropic…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-11 Y. Rappaz , J. Schober

Various experiments indicate the existence of a second knee around energy E=3.10^{17} eV in the cosmic ray spectrum. This feature could be the signature of the end of the galactic component and of the emergence of the extragalactic one,…

Astrophysics · Physics 2008-12-18 Kumiko Kotera , Martin Lemoine

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

We investigate the possibility of measuring intergalactic magnetic fields using the dispersion measures and rotation measures of fast radio bursts. With Bayesian methods, we produce probability density functions for values of these…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-31 Stefan Hackstein , Marcus Brüggen , Franco Vazza , Bryan Gaensler , Volker Heesen

Even though magnetic fields play an important role in galaxy evolution, the redshift evolution of galactic-scale magnetic fields is not well constrained observationally. In this paper we aim to provide an observational constraint on the…

Astrophysics of Galaxies · Physics 2025-07-18 Timea Orsolya Kovacs , Sui Ann Mao , Aritra Basu , Yik Ki Ma , B. M. Gaensler

There are at present more then 30 theories about the origin of cosmic magnetic fields at galactic and intergalactic scales. Most of them rely on concepts of elementary particle physics, like phase transitions in the early Universe, string…

Astrophysics · Physics 2007-05-23 E. Battaner , H. Lesch

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

Weak magnetic fields must have existed in the early Universe, as they were sourced by the cross product of electron density and temperature gradients through the Biermann-battery mechanism. In this paper we calculate the magnetic fields…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-15 Nanoom Lee , Yacine Ali-Haimoud

We present estimates of magnetic field strengths in the interstellar media of starburst galaxies derived from measurements of Zeeman splitting associated with OH megamasers. The results for eight galaxies with Zeeman detections suggest that…

Astrophysics of Galaxies · Physics 2015-06-17 James McBride , Eliot Quataert , Carl Heiles , Amber Bauermeister

We present a search for spatial extension in high-latitude ($|b|>5^\circ$) sources in recent Fermi point source catalogs. The result is the Fermi High-Latitude Extended Sources Catalog, which provides source extensions (or upper limits…

High Energy Astrophysical Phenomena · Physics 2018-09-13 LAT Collaboration , Jonathan Biteau

We present semi-analytical models of galactic outflows in high redshift galaxies driven by both hot thermal gas and non-thermal cosmic rays. Thermal pressure alone may not sustain a large scale outflow in low mass galaxies (i.e $M\sim…

Astrophysics of Galaxies · Physics 2018-02-21 Saumyadip Samui , Kandaswamy Subramanian , Raghunathan Srianand

Ultra-high energy cosmic rays interacting with the radiation fields in the universe cause electromagnetic cascades resulting in a flux of extragalactic gamma rays, detectable to some 100 GeV. Recent precise measurements of the extragalactic…

High Energy Astrophysical Phenomena · Physics 2015-06-19 A. D. Erlykin , A. W. Wolfendale

We present numerical simulations for energy spectra and angular distributions of nucleons above 10^{19} eV injected by the radio-galaxy Centaurus A at a distance 3.4 Mpc and propagating in extra-galactic magnetic fields in the sub-micro…

Astrophysics · Physics 2009-11-06 C. Isola , M. Lemoine , G. Sigl

We study diffuse gamma-ray emission at intermediate Galactic latitudes measured by the Fermi Large Area Telescope with the aim of searching for a signal from dark matter annihilation or decay. In the absence of a robust dark matter signal,…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Gabrijela Zaharijas , Jan Conrad , Alessandro Cuoco , Zhaoyu Yang

Intergalactic space is believed to contain non-zero magnetic fields (the Intergalactic Magnetic Field: IGMF) which at scales of Mpc would have intensities below $10^{-9}$ G. Very high energy (VHE $>$100 GeV) gamma rays coming from blazars…

High Energy Astrophysical Phenomena · Physics 2018-12-19 M. Fernández Alonso , A. D. Supanitsky , A. C. Rovero

We review the possible mechanisms for the generation of cosmological magnetic fields, discuss their evolution in an expanding Universe filled with the cosmic plasma and provide a critical review of the literature on the subject. We put…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 R. Durrer , A. Neronov

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
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