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Various types of magnetic fields occur in stars: small scale fields, large scale fields, and internal toroidal fields. While the latter may be ubiquitous in stars due to differential rotation, small scale fields (spots) may be associated…

Solar and Stellar Astrophysics · Physics 2015-06-18 N. Langer

Magnetic diffusion plays a vital role in star formation. We trace its influence from interstellar cloud scales down to star-disk scales. On both scales, we find that magnetic diffusion can be significantly enhanced by the buildup of strong…

Solar and Stellar Astrophysics · Physics 2013-08-19 Shantanu Basu , Wolf B. Dapp

(abridged) The interpretation of Faraday rotation measure maps of AGNs within galaxy clusters has revealed regions, $\sim 50-100$ kpc, that are populated with large, $\sim 30 \mu$ G magnetic fields. The magnetic energy of these coherent…

Astrophysics · Physics 2009-10-31 S. A. Colgate , H. Li , V. Pariev

About 10% of hot stars host a fossil magnetic field on the pre-main sequence and main sequence. However, the first magnetic evolved hot stars have been discovered only recently. An observing program has been set up to find more such…

Solar and Stellar Astrophysics · Physics 2018-11-14 C. Neiner , A. Martin , G. Wade , M. Oksala

M dwarfs are the most numerous stars in our Galaxy with masses between approximately 0.5 and 0.1 solar mass. Many of them show surface activity qualitatively similar to our Sun and generate flares, high X-ray fluxes, and large-scale…

Solar and Stellar Astrophysics · Physics 2018-01-29 D. Shulyak A. Reiners , A. Engeln , L. Malo , R. Yadav , J. Morin , O. Kochukhov

Chemically peculiar Ap and Bp stars host strong large-scale magnetic fields in the range of $200$~G up to $30$~kG, which are often considered to be the origin of fossil magnetic fields. We assess the evolution of such fossil fields during…

Solar and Stellar Astrophysics · Physics 2023-06-30 Dominik R. G. Schleicher , Juan Pablo Hidalgo , Daniele Galli

We study the generation of strong large scale magnetic fields in compact stars containing degenerate quark matter with unbroken chiral symmetry. The magnetic field growth is owing to the magnetic field instability driven by the electroweak…

High Energy Physics - Phenomenology · Physics 2017-03-27 Maxim Dvornikov

Stellar magnetic dynamos are driven by rotation, rapidly rotating stars produce stronger magnetic fields than slowly rotating stars do. The Zeeman effect is the most important indicator of magnetic fields, but Zeeman broadening must be…

Solar and Stellar Astrophysics · Physics 2015-06-17 Ansgar Reiners

We explore the effects of magnetic energy dissipation on the formation of the first stars. For this purpose, we follow the evolution of primordial chemistry in the presence of magnetic fields in the post-recombination universe until the…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-28 Dominik R. G. Schleicher , Daniele Galli , Simon C. O. Glover , Robi Banerjee , Francesco Palla , Raffaella Schneider , Ralf S. Klessen

Magnetic fields are often invoked as playing a primary role in star formation and in the formation of high-mass stars. We investigate the effect of magnetic fields on the formation of high-mass cores using the 3-dimensional smoothed…

Astrophysics of Galaxies · Physics 2025-04-04 Katerina Sophia Klos , Ian A. Bonnell , Rowan J. Smith

The role of magnetic fields in the early stages of star formation is not well constrained. In order to discriminate between different star formation models, we analyze 3D magnetohydrodynamic simulations of low-mass cores and explore the…

Astrophysics of Galaxies · Physics 2017-01-18 Joyce W. Y. Lee , Charles L. H. Hull , Stella S. R. Offner

Observations have shown the existence of narrow, very long, straight jets emitted by some newly forming stars (1). It is highly likely that stars forming in the plane of a spiral galaxy do so in the presence of an almost uniform magnetic…

Astrophysics · Physics 2009-10-30 Howard D. Greyber

Magnetic fields play an important role at all stages of stellar evolution. In Sun-like stars, they are generated in the outer convective layers. Studying the large-scale magnetic fields of these stars enlightens our understanding of the…

Solar and Stellar Astrophysics · Physics 2015-06-17 R. Fares

Although, from a theoretical point of view, magnetic fields are believed to have a significant role during the early stages of star formation, especially during the main accretion phase, the magnetic field strength and topology is poorly…

The origin of intergalactic magnetic fields is still a mystery and several scenarios have been proposed so far: among them, primordial phase transitions, structure formation shocks and galactic outflows. In this work we investigate how…

Astrophysics · Physics 2009-11-11 Serena Bertone , Corina Vogt , Torsten Ensslin

The origin of supermassive black holes (with $\gtrsim\!10^9\,M_{\odot}$) in the early universe (redshift $z \sim 7$) remains poorly understood. Gravitational collapse of a massive primordial gas cloud is a promising initial process, but…

Astrophysics of Galaxies · Physics 2021-08-18 Shingo Hirano , Masahiro N. Machida , Shantanu Basu

Rotation and magnetism are increasingly recognized as important phenomena in stellar evolution. Surface magnetic fields from a few to $20{,}000\,$G have been observed and models have suggested that magnetohydrodynamic transport of angular…

Solar and Stellar Astrophysics · Physics 2018-04-04 Leo G. Quentin , Christopher A. Tout

Strong, globally-organized magnetic fields are found for a small fraction of O, B, and A stars. At the same time, many theoretical and indirect observational studies suggested ubiquitous presence of weak localized magnetic fields at the…

Solar and Stellar Astrophysics · Physics 2015-06-15 O. Kochukhov , N. Sudnik

We develop an analytical model to follow the cosmological evolution of magnetic fields in disk galaxies. Our assumption is that fields are amplified from a small seed field via magnetohydrodynamical (MHD) turbulence. We further assume that…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Stanislav Shabala , James M. G. Mead , Paul Alexander

For several decades we have been cognizant of the presence of magnetic fields in early-type stars, but our understanding of their magnetic properties has recently (over the last decade) expanded due to the new generation of high-resolution…

Solar and Stellar Astrophysics · Physics 2015-06-16 Jason H. Grunhut , Coralie Neiner