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Stars and gaseous planets are magnetised objects but the influence of magnetic fields on their tidal responses and dissipation rates has not been well explored. We present the first exploratory nonlinear magnetohydrodynamic (MHD)…

Solar and Stellar Astrophysics · Physics 2024-11-26 Aurélie Astoul , Adrian J. Barker

We study the effect of primordial magnetic fields (PMFs) on the anisotropies of the cosmic microwave background (CMB). We assume the spectrum of PMFs is described by log-normal distribution which has a characteristic scale, rather than…

Cosmology and Nongalactic Astrophysics · Physics 2011-12-30 Dai G. Yamazaki , Kiyotomo Ichiki , Keitaro Takahashi

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

Large scale strong magnetic fields in galaxies are generally thought to have been generated by a mean field dynamo. In order to have generated the fields observed, the dynamo would have had to have operated for a sufficiently long period of…

Astrophysics · Physics 2007-05-23 A. Kandus , R. Opher , S. R. M. Barros

White dwarf atmospheres are subjected to gravitational potentials around $10^5$ times larger than occur on Earth. They provide a unique environment in which to search for any possible variation in fundamental physics in the presence of…

The origin of cosmic magnetic fields is an unsolved problem and magnetogenesis could have occurred in the early Universe. We study the evolution of such primordial magnetic fields across the cosmological recombination epoch via 3D…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-25 Pranjal Trivedi , Johannes Reppin , Jens Chluba , Robi Banerjee

The origin and maintenance of coherent magnetic fields in the Universe is reviewed with an emphasis on the possible challenges that arise in their theoretical understanding. We begin with the interesting possibility that magnetic fields…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-12 Kandaswamy Subramanian

The existence of primordial magnetic fields can induce matter perturbations with additional power at small scales as compared to the usual $\Lambda$CDM model. We study its implication within the context of two-point shear correlation…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Kanhaiya L. Pandey , Shiv K. Sethi

Little is known about the incidence of magnetic fields among the coolest white dwarfs. Their spectra usually do not exhibit any absorption lines as the bound-bound opacities of hydrogen and helium are vanishingly small. Probing these stars…

Solar and Stellar Astrophysics · Physics 2015-06-24 Mark Hollands , Boris Gaensicke , Detlev Koester

Magnetic fields constitute an energetic component of the interstellar medium in galaxies and hence can affect the formation of galactic structures. Sensitive resolved radio continuum observations together with statistical studies in galaxy…

Astrophysics of Galaxies · Physics 2018-11-20 Fatemeh S. Tabatabaei

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

We derive an upper limit of $B_0<3.4\times 10^{-9}(\Omega_0h_{50}^2)^{1/2}$ Gauss on the present strength of any primordial homogeneous magnetic field. The microwave background anisotropy created by cosmological magnetic fields is…

Astrophysics · Physics 2016-08-30 John D. Barrow , Pedro G. Ferreira , Joseph Silk

Violent gravitational interactions can change the morphologies of galaxies and, by means of merging, transform them into elliptical galaxies. We aim to investigate how they affect the evolution of galactic magnetic fields. We selected 16…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-23 Robert T. Drzazga , Krzysztof T. Chyzy , Wojciech Jurusik , Krzysztof Wiorkiewicz

We calculate the effect that a primordial homogeneous magnetic field, $\B_0$, will have on the different CMB power spectra due to Faraday rotation. Concentrating on the $TB$, $EB$ and $BB$ correlations, we forecast the ability for future…

Astrophysics · Physics 2008-11-26 Jostein R. Kristiansen , Pedro G. Ferreira

Simulations are presented of the photoionisation of three dense gas clouds threaded by magnetic fields, showing the dynamical effects of different initial magnetic field orientations and strengths. For moderate magnetic field strengths the…

Astrophysics of Galaxies · Physics 2013-01-08 Jonathan Mackey , Andrew J. Lim

We propose a novel mechanism to generate primordial magnetic fields (PMFs) strong enough to explain the observed cosmic magnetic fields. We employ a scalar field charged under U(1) gauge symmetry with a non-trivial VEV to provide an…

High Energy Physics - Phenomenology · Physics 2025-11-26 Alexander Ganz , Chunshan Lin , Mian Zhu

In star formation, magnetic fields act as a cosmic angular momentum extractor that increases mass accretion rates onto protostars and in the process, creates spectacular outflows. However, recently it has been argued that this magnetic…

Solar and Stellar Astrophysics · Physics 2014-11-20 Dennis F. Duffin , Ralph E. Pudritz

We have measured the surface magnetic flux on four accreting young brown dwarfs and one non-accreting young very low-mass star utilizing high resolution spectra of absorption lines of the FeH molecule. A magnetic field of 1-2 kG had been…

Solar and Stellar Astrophysics · Physics 2011-02-11 Ansgar Reiners , Gibor Basri , Ulrich R. Christensen

The galactic magnetic field is commonly supposed to be due to a dynamo acting on some large scale seed field. A major difficulty with this idea is that estimates of reasonable seed field strengths tend to be quite low, on the order of…

Astrophysics · Physics 2007-05-23 Ethan T. Vishniac

We point out that the lower bound on the primordial magnetic field required to seed the galactic dynamo is significantly relaxed in an open universe or in a universe with a positive cosmological constant. It is shown that, for reasonable…

Astrophysics · Physics 2008-11-26 Anne-Christine Davis , Matthew Lilley , Ola Tornkvist