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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,…

A primordial magnetic field (PMF) can affect the evolution of density field fluctuations in the early universe.In this paper we constrain the PMF amplitude $B_\lambda$ and power spectral index $n_\mathrm{B}$ by comparing calculated density…

Astrophysics · Physics 2008-12-18 Dai G. Yamazaki , Kiyotomo Ichiki , Toshitaka Kajino , Grant. J. Mathews

The presence of primordial magnetic fields increases the minimum halo mass in which star formation is possible at high redshifts. Estimates of the dynamical mass of ultra-faint dwarf galaxies (UFDs) within their half-light radius constrain…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-05 Mohammadtaher Safarzadeh , Abraham Loeb

We derive the magnitude of fluctuations in total synchrotron intensity in the Milky Way and M33, from both observations and theory under various assumption about the relation between cosmic rays and interstellar magnetic fields. Given the…

Astrophysics of Galaxies · Physics 2016-01-05 Rodion Stepanov , Anvar Shukurov , Andrew Fletcher , Rainer Beck , Laura La Porta , Fatemeh Tabatabaei

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

We study the properties of magnetic fields in the circumgalactic medium (CGM) of $z<1$ galaxies by correlating Faraday rotation measures of $\sim 1,000$ high-redshift radio sources with the foreground galaxy number density estimated from…

Astrophysics of Galaxies · Physics 2020-06-24 Ting-Wen Lan , J. Xavier Prochaska

Assuming that the hard gamma-ray emission of Cen A is a result of synchrotron radiation of ultra-relativistic electrons, we derive a lower bound on the local extragalactic magnetic field, $B> 10^{-8}$ G. This result is consistent with (and…

High Energy Physics - Phenomenology · Physics 2009-11-07 Luis A. Anchordoqui , Haim Goldberg

Understanding the role of magnetic fields in star-forming regions is of fundamental importance. In the near future, the exceptional sensitivity of SKA will offer a unique opportunity to evaluate the magnetic field strength in molecular…

High Energy Astrophysical Phenomena · Physics 2018-12-12 Marco Padovani , Daniele Galli

We describe a technique for using simulated tensor perturbations in order to place upper limits on the intensity of magnetic fields in the early universe. As an example, we apply this technique to the beginning of primordial…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-09 David Garrison

We improve on the model of the Galactic Magnetic Field (GMF) from Jansson \& Farrar (2012), which was constrained using all-sky rotation measures of extragalactic sources and polarized and unpolarized synchrotron emission data from WMAP. We…

Astrophysics of Galaxies · Physics 2017-07-14 Michael Unger , Glennys R. Farrar

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 simulate the propagation of cosmic rays at ultra-high energies, $\gtrsim 10^{18}$ eV, in models of extragalactic magnetic fields in constrained simulations of the local Universe. We use constrained initial conditions with the…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-08 Stefan Hackstein , Franco Vazza , Marcus Brüggen , Jenny G. Sorce , Stefan Gottlöber

Synchrotron emission, its polarization and its Faraday rotation at radio frequencies of 0.2-10 GHz are powerful tools to study the strength and structure of cosmic magnetic fields. The observational results are reviewed for spiral, barred…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Rainer Beck

Synchrotron radiation from cosmic rays is a key observational probe of the galactic magnetic field. Interpreting synchrotron emission data requires knowledge of the cosmic ray number density, which is often assumed to be in energy…

Astrophysics of Galaxies · Physics 2017-12-06 Amit Seta , Anvar Shukurov , Toby S. Wood , Paul J. Bushby , Andrew P. Snodin

Ultra-high energy cosmic rays can propagate diffusively in cosmic magnetic fields. When their propagation time is comparable to the age of the universe, a suppression in the flux relative to the case in the absence of magnetic fields will…

High Energy Astrophysical Phenomena · Physics 2014-12-10 Rafael Alves Batista , Guenter Sigl

High energy cosmic ray electrons and positrons, during propagation in the Galaxy, mainly lose energy through either the inverse Compton scattering (ICS) off of the interstellar radiation field (ISRF) or emitting synchrotron radiation in the…

High Energy Astrophysical Phenomena · Physics 2017-09-13 Maryam Tavakoli

Earlier Bamba et al [JCAP (2012)] have obtained cosmological magnetic fields in teleparallel torsion theories of gravity that are not compatible with galactic dynamos. This result agrees with previous ones obtained by the author which shows…

Cosmology and Nongalactic Astrophysics · Physics 2013-07-02 Luiz Carlos Garcia de Andrade

A three-dimensional (3D) MHD model is applied to simulate the evolution of a large-scale magnetic field in a barred galaxy possessing a gaseous halo extending to about 2.8 kpc above the galactic plane. As the model input we use a…

Astrophysics · Physics 2009-11-07 K. Otmianowska-Mazur , D. Elstner , M. Soida , M. Urbanik

In view of several conflicting results, we reanalyze the effects of magnetic fields on the primordial nucleosynthesis. In the case the magnetic field is homogeneous over a horizon volume, we show that the main effects of the magnetic field…

Astrophysics · Physics 2008-11-26 D. Grasso , H. R. Rubinstein

Large-scale intergalactic magnetic fields may contain a mixture of galactic and cosmogenic contributions, that can be probed via observations of $\gamma$-ray "echo" - a delayed emission from electromagnetic cascades initiated by the highest…

High Energy Astrophysical Phenomena · Physics 2026-02-10 Ievgen Vovk
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