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The origin of the substantial magnetic fields that are found in galaxies and on even larger scales, such as in clusters of galaxies, is yet unclear. If the second-order couplings between photons and electrons are considered, then…

Here, we analyze the primordial magnetic field transition between a radiative and a matter-dominated universe. The gravitational structure formation affects its evolution and energy spectrum. The structure excitation can trigger magnetic…

Astrophysics · Physics 2009-11-10 Grazyna Siemieniec-Ozieblo

Cosmological magnetic fields in open Friedmann universes can experience superadiabatic amplification within the realm of conventional electromagnetism. This is possible mathematically, despite the conformal invariance of Maxwell's…

General Relativity and Quantum Cosmology · Physics 2015-06-05 J. D. Barrow , C. G. Tsagas , K. Yamamoto

Magnetic fields appear wherever plasma and currents can be found. As such, they thread through all scales in Nature. It is natural, therefore, to suppose that magnetic fields might have been formed within the high temperature environments…

Cosmology and Nongalactic Astrophysics · Physics 2012-08-16 Dai G. Yamazaki , Toshitaka Kajino , Grant J. Mathew , Kiyotomo Ichiki

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

The evolution of the magnetic field is investigated for isolated as well as binary neutron stars. The overall nature of the field evolution is seen to be similar for an initial crustal field and an expelled flux. The major uncertainties of…

Astrophysics · Physics 2007-05-23 Sushan Konar , Dipankar Bhattacharya

Observations are inconsistent with a homogeneous and isotropic universe with ordinary matter and gravity. The universe is far from exact homogeneity and isotropy at late times, and the effect of the non-linear structures has to be…

Astrophysics · Physics 2012-05-01 Syksy Rasanen

In growing neutrino models, the neutrino mass increases in time and stops the dynamical evolution of a dark energy scalar field, thus explaining the 'why now' problem. A new attractive force, mediated by the 'cosmon' scalar field, makes non…

Cosmology and Nongalactic Astrophysics · Physics 2009-05-07 Christof Wetterich , Valeria Pettorino

In this thesis, we aim to investigate the mechanisms underlying the genesis of magnetic fields in the Universe and explore their potential in addressing the matter-antimatter asymmetry. We construct consistent models that generate the…

General Relativity and Quantum Cosmology · Physics 2024-03-21 Ashu Kushwaha

We examine the growth of structure in three different cosmological models with interacting dark matter and vacuum energy. We consider the case of geodesic dark matter with zero sound speed, where the relativistic growing mode in…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-20 Humberto A Borges , David Wands

To investigate the role of magnetic fields in the evolution of the interstellar medium, formation and evolution of molecular clouds, and ultimately the formation of stars, their three-dimensional (3D) magnetic fields must be probed.…

Astrophysics of Galaxies · Physics 2022-09-27 Mehrnoosh Tahani

We examine the evolution of magnetic fields in an expanding fluid composed of matter and radiation with particular interest in the evolution of cosmic magnetic fields. We derive the propagation velocities and damping rates for relativistic…

Astrophysics · Physics 2009-10-28 K. Jedamzik , V. Katalinic , A. Olinto

Magnetic fields appear to be ubiquitous in astrophysical environments. Their existence in the intracluster medium is established through observations of synchrotron emission and Faraday rotation. On the other hand, the nature of magnetic…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Dongsu Ryu , Dominik R. G. Schleicher , Rudolf A. Treumann , Christos G. Tsagas , Lawrence M. Widrow

I review a class of nonlocally modified gravity models which were proposed to explain the current phase of cosmic acceleration without dark energy. Among the topics considered are deriving causal and conserved field equations, adjusting the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 R. P. Woodard

The creation of large scale magnetic fields is studied in an inflationary universe where electrodynamics is assumed to be nonlinear. After inflation ends electrodynamics becomes linear and thus the description of reheating and the…

Astrophysics · Physics 2008-11-26 Kerstin E. Kunze

The origin of large scale cosmological magnetic fields remains a mystery, despite the continuous efforts devoted to that problem. We present a new model of magnetic field generation, based on local charge separation provided by an…

Astrophysics · Physics 2009-04-16 Mathieu Langer , Jean-Loup Puget , Nabila Aghanim

The observed galactic magnetic fields may have a primordial origin. I briefly review the observations, their interpretation in terms of the dynamo theory, and the current limits on cosmological magnetic fields. Several possible mechanisms…

Astrophysics · Physics 2007-05-23 Kari Enqvist

We carry out 3D and 2D PIC-simulations of the expansion of a magnetized plasma that initially uniformly fills a half-space and contains a semi-cylindrical region of heated electrons elongated along the surface of the plasma boundary. This…

We investigate the evolution of the magnetic field of isolated pulsars and of neutron stars in different kinds of binary systems, assuming the field to be originally confined to the crust. Our results for the field evolution in isolated…

Astrophysics · Physics 2009-10-30 Sushan Konar , Dipankar Bhattacharya

In this paper we show that noncommutativity in spatial coordinates can generate magnetic field in the early Universe on a horizon scale. The strength of such a magnetic field depends on the number density of massive charged particles…

High Energy Physics - Phenomenology · Physics 2009-10-07 Anupam Mazumdar , Mohammad M. Sheikh-Jabbari