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A short introduction to structure formation is given, followed by a discussion of the possible characteristics of the initial perturbations assuming a generic inflationary origin. Observational data related to large-scale structure and the…

Astrophysics · Physics 2014-10-13 Pedro Viana

Observations of $\gamma$-ray from blazars suggest the presence of magnetic fields in the intergalactic medium, which may require a primordial origin. Intense enough primordial magnetic fields can arise from theories of dynamical electroweak…

High Energy Physics - Phenomenology · Physics 2025-09-26 Martin Arteaga Tupia , Anish Ghoshal , Alessandro Strumia

Inflation has long been thought as the best way of producing primordial large-scale magnetic fields. To achieve fields strong enough to seed the galactic dynamo, most of the mechanisms operate outside conventional electromagnetic theory.…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-09 Christos G. Tsagas

We study the primordial magnetic field generated by stochastic currents produced by scalar charged particles created at the beginning of the radiation dominated epoch. We find that for the mass range 10^(-6)GeV \leq m \leq 10^2 GeV, a field…

Astrophysics · Physics 2008-11-26 Esteban A. Calzetta , Alejandra Kandus , Francisco D. Mazzitelli

High-scale string inflationary models are in well-known tension with low-energy supersymmetry. A promising solution involves models where the inflaton is the volume of the extra dimensions so that the gravitino mass relaxes from large…

High Energy Physics - Theory · Physics 2016-01-20 Michele Cicoli , Francesco Muia , Francisco Gil Pedro

We present a simplified model in which we suggest that two important galactic problems -the magnetic field configuration at large scales and the flat rotation curve- may be simultaneously explained. A highly convective disc produces a high…

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

Magnetic fields are present on all scales in the Universe. While we understand the processes which amplify the fields fairly well, we do not have a "natural" mechanism to generate the small initial seed fields. By using fully relativistic…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-18 Ellie Nalson , Adam J. Christopherson , Karim A. Malik

The magnetogenesis scenarios triggered by the early variation of the gauge coupling are critically analyzed. In the absence of sources, it is shown that the electric and magnetic power spectra can be explicitly computed by means of…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-29 Massimo Giovannini

Mechanisms of generation of magnetic fields in the early universe which could seed the present-day large scale galactic magnetic fields, are briefly reviewed. Three possible ways to create large scale magnetic fields are discussed: breaking…

High Energy Physics - Phenomenology · Physics 2016-11-23 A. D. Dolgov

The existence of magnetic fields associated with the intracluster medium in clusters of galaxies is now well established through different methods of analysis. The most detailed evidence for the presence of cluster magnetic fields comes…

Astrophysics · Physics 2009-11-11 Federica Govoni

We investigate the generation of primordial magnetic fields from stochastic currents created by the cosmological transition from inflation to reheating. We consider N charged scalar fields coupled to the electromagnetic field in a curved…

Astrophysics · Physics 2009-11-07 Esteban Calzetta , Alejandra Kandus

We explore the generation of large-scale magnetic fields from inflation in teleparallelism, in which the gravitational theory is described by the torsion scalar instead of the scalar curvature in general relativity. In particular, we…

Cosmology and Nongalactic Astrophysics · Physics 2012-11-02 Kazuharu Bamba , Chao-Qiang Geng , Ling-Wei Luo

Primordial magnetogenesis is an intriguing possibility to explain the origin of intergalactic magnetic fields (IGMFs). However, the baryon isocurvature problem has recently been pointed out, ruling out all magnetogenesis models operating…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-08 Kazuki Yanagihara , Fumio Uchida , Tomohiro Fujita , Shinji Tsujikawa

We review the literature concerning how the cosmic magnetic fields pervading nearly all galaxies actually got started. some observational evidence involves the chemical abundance of the light elements Be and B, while another one is based on…

Astrophysics · Physics 2009-11-13 Russell M. Kulsrud , Ellen G. Zweibel

Observations of stable mainly dipolar magnetic fields at the surface of ~7% of single hot stars indicate that these fields are of fossil origin, i.e. they descend from the seed field in the molecular clouds from which the stars were formed.…

Solar and Stellar Astrophysics · Physics 2015-02-03 C. Neiner , S. Mathis , E. Alecian , C. Emeriau , J. Grunhut , the BinaMIcS , MiMeS collaborations

We clarify the causal structure of an inflating magnetic monopole. The spacetime diagram shows explicitly that this model is free from ``graceful exit'' problem, while the monopole itself undergoes ``eternal inflation''. We also discuss…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Nobuyuki Sakai , Ken-ichi Nakao , Tomohiro Harada

We review our current understanding of galactic dynamo theory, paying particular attention to numerical simulations both of the mean-field equations and the original three-dimensional equations relevant to describing the magnetic field…

Astrophysics of Galaxies · Physics 2014-12-12 Axel Brandenburg

Despite their ubiquity, the origin of cosmic magnetic fields remains unknown. Various mechanisms have been proposed for their existence including primordial fields generated by inflation, or amplification and injection by compact…

Cosmology and Nongalactic Astrophysics · Physics 2019-01-23 Harley Katz , Sergio Martin-Alvarez , Julien Devriendt , Adrianne Slyz , Taysun Kimm

Spontaneous breaking of Lorentz invariance may take place in string theories, possibly endowing the photon with a mass. This leads to the breaking of the conformal symmetry of the electromagnetic action allowing for the generation within…

General Relativity and Quantum Cosmology · Physics 2007-05-23 O. Bertolami , D. F. Mota

Inflation is the leading paradigm for explaining the origin of primordial density perturbations and the observed temperature fluctuations of the cosmic microwave background. However many open questions remain, in particular whether one or…

High Energy Physics - Theory · Physics 2015-06-05 Gianmassimo Tasinato , Christian T. Byrnes , Sami Nurmi , David Wands
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