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The amplification of the primordial magnetic fields and the gravitational baryogenesis, a mechanism that allows to generate the baryon asymmetry in the Universe by means of the coupling between the Ricci scalar curvature and the baryon…

Cosmology and Nongalactic Astrophysics · Physics 2009-08-18 Herman J. Mosquera Cuesta , Gaetano Lambiase

Detailed physical processes of magnetic field generation from density fluctuations in the pre-recombination era are studied. Solving Maxwell equations and the generalized Ohm's law, the evolutions of the net charge density, the electric…

Astrophysics · Physics 2008-11-26 Keitaro Takahashi , Kiyotomo Ichiki , Naoshi Sugiyama

Galaxies are observed to host magnetic fields with a typical total strength of around 15microgauss. A coherent large-scale field constitutes up to a few microgauss of the total, while the rest is built from strong magnetic fluctuations over…

Astrophysics of Galaxies · Physics 2024-01-09 Maarit J. Korpi-Lagg , Mordecai-Mark Mac Low , Frederick A. Gent

(abridged) We suggest here that the large scale fields $\sim \mu$G, observed in galaxies at both high and low redshifts by Faraday Rotation Measurements (FRMs), have their origin in the electromagnetic fluctuations that naturally occurred…

Astrophysics · Physics 2008-11-26 Rafael S. de Souza , Reuven Opher

We consider the process of magnetogenesis in the context of nonsingular bounce cosmology. We show that large primordial magnetic fields can be generated during contraction without encountering strong coupling and backreaction issues. The…

General Relativity and Quantum Cosmology · Physics 2016-11-02 Peng Qian , Yi-Fu Cai , Damien A. Easson , Zong-Kuan Guo

Several mechanisms have been proposed to generate primordial magnetic fields and it is often assumed that magnetic fields are not affected by a sharp drop in ionization rate due to the cosmic recombination. We investigate the validity of…

Astrophysics · Physics 2008-04-23 Keitaro Takahashi

We revisit the method of using the photon-graviton conversion mechanism in the presence of the external magnetic field to probe small-scale primordial magnetic fields that may exist between the last scattering surface and present.…

Cosmology and Nongalactic Astrophysics · Physics 2014-01-01 Pisin Chen , Teruaki Suyama

The origin of cosmic magnetism is an issue of fundamental importance in astrophysics. We review here some of the ideas of how large scale magnetic fields in the universe, particularly in galaxies and galaxy clusters could arise. The popular…

Astrophysics · Physics 2009-06-23 Kandaswamy Subramanian

$\gamma$-ray emission of blazars infer the presence of large-scale magnetic fields in the intergalactic medium, but their origin remains a mystery. Using recent data from MAGIC, H.E.S.S. and $\textit{Fermi}$-LAT, we investigate whether the…

High Energy Physics - Phenomenology · Physics 2024-05-07 María Olalla Olea-Romacho

The true nature of primordial magnetic fields (PMFs) and their role in the formation of galaxies still remains elusive. To shed light on these unknowns, we investigate their impact by varying two sets of properties: (i) accounting for the…

Astrophysics of Galaxies · Physics 2024-10-02 Mahsa Sanati , Sergio Martin-Alvarez , Jennifer Schober , Yves Revaz , Adrianne Slyz , Julien Devriendt

Primordial magnetic fields (PMFs) may significantly influence 21-cm physics via two mechanisms: (i) magnetic heating of the intergalactic medium (IGM) through ambipolar diffusion (AD) and decaying magnetohydrodynamic turbulence (DT), (ii)…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-27 Arko Bhaumik , Debarun Paul , Supratik Pal

We study the evolution of magnetic fields in turbulent hot plasma of the early Universe accounting for the chiral magnetic effect. The magnetohydrodynamic turbulence is modeled by replacing the matter velocity in the advection term in the…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-17 Maxim Dvornikov

The origin and growth of magnetic fields in galaxies is still something of an enigma. It is generally assumed that seed fields are amplified over time through the dynamo effect, but there are few constraints on the timescale. It has…

Neutron stars, and magnetars in particular, are known to host the strongest magnetic fields in the Universe. The origin of these strong fields is a matter of controversy. In this preliminary work, via numerical simulations, we study, for…

High Energy Astrophysical Phenomena · Physics 2020-06-30 K. Franceschetti , L. Del Zanna

Cosmic strings are a type of cosmic defect formed by a symmetry-breaking phase transition in the early universe. Individual strings would have gathered to build a network, and their dynamical motion would induce scalar--, vector-- and…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-07 Kouichirou Horiguchi , Kiyotomo Ichiki , Naoshi Sugiyama

Cosmological hydrodynamical simulations of primordial star formation suggest that the gas within the first star-forming halos is turbulent. This has strong implications on the subsequent evolution, in particular on the generation of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Sharanya Sur , Dominik R. G. Schleicher , Robi Banerjee , Christoph Federrath , Ralf S. Klessen

Cosmological simulations of magnetic fields in galaxy clusters show that remarkable agreement between simulations and observations of Faraday rotation and radio haloes can be achieved assuming that seed fields of 10^{-9} G were present at…

Astrophysics · Physics 2007-05-23 Matthias Bartelmann , Klaus Dolag , Harald Lesch

We extend our recent derivation of the time evolution equations for the energy content of magnetic fields and turbulent motions for incompressible, homogeneous, and isotropic turbulence to include the case of nonvanishing helicity. These…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-14 Andrey Saveliev , Karsten Jedamzik , Guenter Sigl

Magnetic fields in nearby, star-forming galaxies reveal both large-scale patterns and small-scale structures. A large-scale field reversal may exist in the Milky Way but no such reversals have been observed so far in external galaxies. The…

Astrophysics of Galaxies · Physics 2015-05-30 David Moss , Rodion Stepanov , Tigran Arshakian , Rainer Beck , Marita Krause , Dmitri Sokoloff

A variety of observations suggest that magnetic fields are present in all galaxies and galaxy clusters. These fields are characterized by a modest strength (10^{-7}-10^{-5} G) and huge spatial scale (~Mpc). It is generally assumed that…

Astrophysics · Physics 2008-11-26 Lawrence M. Widrow