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We propose a primordial-origin model for the composite configurations of global magnetic fields in spiral galaxies. We show that uniform tilted magnetic field wound up into a rotating disk galaxy can evolve into composite magnetic…

Astrophysics of Galaxies · Physics 2015-05-19 Yoshiaki Sofue , Mami Machida , Takahiro Kudoh

In this paper we develop a framework for studying unstratified, magnetised eccentric discs and compute uniformly precessing eccentric modes in a cylindrical annulus which provide convenient initial conditions for numerical simulations. The…

High Energy Astrophysical Phenomena · Physics 2023-09-18 Elliot M. Lynch , Janosz W. Dewberry

Galaxy mergers are expected to play a central role for the evolution of galaxies, and may have a strong impact on their magnetic fields. We present the first grid-based 3D magneto-hydrodynamical simulations investigating the evolution of…

Astrophysics of Galaxies · Physics 2016-09-28 Kai Rodenbeck , Dominik R. G. Schleicher

Interstellar magnetic fields are strong: up to 25 muG in spiral arms and 40 muG in nuclear regions. In the spiral galaxy NGC 6946 the average magnetic energy density exceeds that of the thermal gas. Magnetic fields control the evolution of…

Astrophysics · Physics 2017-01-25 Rainer Beck

A review of galactic magnetic fields is given with emphasis on simple analytical solutions of relevant equations and detailed comparison with observations. It is shown that mean-field dynamo theory, in its simplest form, is in a remarkably…

Astrophysics · Physics 2007-05-23 Anvar Shukurov

We present a model for the seeding and evolution of magnetic fields in protogalaxies. Supernova (SN) explosions during the assembly of a protogalaxy provide magnetic seed fields, which are subsequently amplified by compression, shear flows…

Astrophysics of Galaxies · Physics 2015-06-16 Alexander M. Beck , Klaus Dolag , Harald Lesch , Philipp P. Kronberg

Magnetic fields have been observed in massive Ap/Bp stars and presumably are also present in the radiative zone of solar-like stars. Yet, to date there is no clear understanding of the dynamics of the magnetic field in stably stratified…

Solar and Stellar Astrophysics · Physics 2023-03-27 G. Monteiro , G. Guerrero , F. Del Sordo , A. Bonanno , P. K. Smolarkiewicz

We present three-dimensional global numerical simulations of the cosmic-ray (CR) driven dynamo in barred galaxies. We study the evolution of the interstellar medium of the barred galaxy in the presence of non-axisymmetric component of the…

Astrophysics of Galaxies · Physics 2011-06-02 K. Kulpa-Dybeł , K. Otmianowska-Mazur , B. Kulesza-Żydzik , G. Kowal , M. Hanasz , D. Wóltański , K. Kowalik

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

The question of the origin and evolution of magnetic fields in stars possessing a radiative envelope, like the A-type stars, is still regarded as a challenge for stellar physics. Those zones are likely to be differentially rotating, which…

Solar and Stellar Astrophysics · Physics 2015-06-23 Laurène Jouve , Thomas Gastine , François Lignières

We use high-resolution MHD simulations of isolated disk galaxies to investigate the co-evolution of magnetic fields with a self-regulated, star-forming interstellar medium (ISM). The simulations are conducted using the Ramses AMR code on…

Astrophysics of Galaxies · Physics 2024-06-05 Hector Robinson , James Wadsley

We study the evolution of galactic magnetic fields using 3D smoothed particle magnetohydrodynamics (SPMHD) simulations of galaxies with an imposed spiral potential. We consider the appearance of reversals of the field, and amplification of…

Astrophysics of Galaxies · Physics 2016-09-07 C. L. Dobbs , D. J. Price , A. R. Pettitt , M. R. Bate , T. Tricco

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

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

A framework is introduced for coupling the evolution of galactic magnetic fields sustained by the mean-field dynamo with the formation and evolution of galaxies in cold dark matter cosmology. Estimates of the steady-state strength of the…

Astrophysics of Galaxies · Physics 2015-05-20 Luiz Felippe S. Rodrigues , Anvar Shukurov , Andrew Fletcher , Carlton Baugh

Magnetic fields are ubiquitous in the universe and an important component of the interstellar medium. It is crucial to accurately model and understand their properties in different environments and across all mass ranges of galaxies to…

Astrophysics of Galaxies · Physics 2025-12-22 Maria Werhahn , Rüdiger Pakmor , Rebekka Bieri , Freeke van de Voort , Rosie Y. Talbot , Volker Springel

Radio observations show that magnetic fields are present in dwarf irregular galaxies (dIrr) and its strength is comparable to that found in spiral galaxies. Slow rotation, weak shear and shallow gravitational potential are the main features…

Astrophysics of Galaxies · Physics 2015-05-27 H. Siejkowski , M. Soida , K. Otmianowska-Mazur , M. Hanasz , D. J. Bomans

Recent developments in computer hardware and software enable researchers to simulate the self-gravitating evolution of galaxies at a resolution comparable to the actual number of stars. Here we present the results of a series of such…

Astrophysics of Galaxies · Physics 2018-04-04 Michiko S. Fujii , Jeroen Bédorf , Junichi Baba , Simon Portegies Zwart

We perform three-dimensional numerical simulations of stellar winds of early-M dwarf stars. Our simulations incorporate observationally reconstructed large-scale surface magnetic maps, suggesting that the complexity of the magnetic field…

Solar and Stellar Astrophysics · Physics 2015-06-18 A. A. Vidotto , M. Jardine , J. Morin , J. F. Donati , M. Opher , T. I. Gombosi

Magnetic fields permeate the Universe on all scales and play a key role during star formation. We study the evolution of magnetic fields around a massive metal-free (Population III) star at $z \sim 15$ during the growth of its HII region…

Astrophysics of Galaxies · Physics 2016-08-03 Daegene Koh , John H. Wise