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We present a model of the global magnetic field in the barred galaxy NGC 1365 based jointly on the large-scale velocity field of interstellar gas fitted to HI and CO observations of this galaxy and on mean-field dynamo theory. The aim of…

Astrophysics · Physics 2009-11-13 D. Moss , A. P. Snodin , P. Englmaier , A. Shukurov , R. Beck , D. D. Sokoloff

Irregular galaxies are usually smaller and less massive than their spiral, S0, and elliptical counterparts. Radio observations indicate that a magnetic field is present in irregular galaxies whose value is similar to that in spiral…

Astrophysics of Galaxies · Physics 2014-11-20 H. Siejkowski , M. Soida , K. Otmianowska-Mazur , M. Hanasz , D. J. Bomans

We present an effectively global analytical asymptotic galactic dynamo solution for the regular magnetic field of an axisymmetric thin disc in the saturated state. This solution is constructed by combining two well-known types of local…

Astrophysics of Galaxies · Physics 2016-09-02 Luke Chamandy

The mean-field dynamo model is employed to study the non-linear dynamo regimes in a fully convective star of mass 0.3$M_{\odot}$ rotating with period of 10 days. For the intermediate value of the parameter of the turbulent magnetic Prandl…

Solar and Stellar Astrophysics · Physics 2017-02-01 V. V. Pipin

We study the global consequences in the halos of spiral galaxies of the steady, axially symmetric, mean field dynamo. We use the classical theory but add the possibility of using the velocity field components as parameters in addition to…

Astrophysics of Galaxies · Physics 2017-06-21 R. N. Henriksen

Understanding the numerical dependencies that act on the galactic dynamo is a crucial step in determining what resolution and what conditions are required to properly capture the magnetic fields observed in galaxies. Here, we present an…

Astrophysics of Galaxies · Physics 2023-05-03 Robert Wissing , Sijing Shen

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

We investigate the cosmic ray driven dynamo in the interstellar medium of irregular galaxy. The observations (Chyzy et al. 2000, 2003) show that the magnetic field in irregular galaxies is present and its value reaches the same level as in…

High Energy Astrophysical Phenomena · Physics 2009-11-13 Hubert Siejkowski , Marian Soida , Katarzyna Otmianowska-Mazur , Michał Hanasz , Dominik Bomans

This paper presents scale invariant/self-similar galactic magnetic dynamo models based on the classic equations, and compares them qualitatively to recently observed magnetic fields in edge-on spiral galaxies. We classify the axially…

Astrophysics of Galaxies · Physics 2021-11-03 R. H. Henriksen , Judith Irwin

After a short introduction on how we get information of the magnetic fields from radio observations I discuss the results concerning the magnetic field structure in galaxies: Large-scale regular magnetic field pattern of spiral structure…

Astrophysics · Physics 2007-05-23 M. Krause

Numerical dynamo models always employ parameter values that differ by orders of magnitude from the values expected in natural objects. However, such models have been successful in qualitatively reproducing properties of planetary and…

Solar and Stellar Astrophysics · Physics 2015-06-15 Rakesh K. Yadav , Thomas Gastine , Ulrich R. Christensen , Lúcia D. V. Duarte

Magnetic fields have been included in cosmological simulations of galaxy formation only recently, due to advances in numerical techniques and a better understanding of the galaxy formation physics. In this paper, we develop a new subgrid…

Astrophysics of Galaxies · Physics 2022-05-13 Yuankang Liu , Michael Kretschmer , Romain Teyssier

We study the generation and maintenance of large-scale magnetic fields in barred galaxies. We take a velocity field (with strong noncircular components) from a published gas dynamical simulation of Athanassoula (1992), and use this as input…

Astrophysics · Physics 2009-11-06 D. Moss , A. Shukurov , D. Sokoloff , R. Beck , A. Fletcher

We present kinematic simulations of a galactic dynamo model based on the large scale differential rotation and the small scale helical fluctuations due to supernova explosions. We report for the first time direct numerical simulations of…

Astrophysics of Galaxies · Physics 2009-11-13 Christophe Gissinger , Sebastien Fromang , Emmanuel Dormy

Our purpose is to place firm observational constraints on the three most widely used theoretical models for the spatial configuration of the large-scale interstellar magnetic field in the Galactic disk, namely, the ring, the axisymmetric…

Astrophysics · Physics 2009-11-13 H. Men , K. Ferriere , J. L. Han

We analyzed ionized gas motion and disk orientation parameters for 15 spiral galaxies. Their velocity fields were measured with the H-alpha emission line by using the Fabry-Perot interferometer at the 6m telescope of SAO RAS. Special…

We built a family of non-axisymmetric potential models for normal non-barred or weakly-barred spiral galaxies as defined in the simplest classification of galaxies: the Hubble sequence. For this purpose a three-dimensional self-gravitating…

Astrophysics of Galaxies · Physics 2015-06-16 A. Pérez-Villegas , B. Pichardo , E. Moreno

Magnetic fields in galaxies are believed to be the result of dynamo amplification of initially weak seed fields, reaching equipartition strength inside the interstellar medium. The small-scale dynamo appears to be a viable mechanism to…

Astrophysics of Galaxies · Physics 2017-08-16 Michael Rieder , Romain Teyssier

An update is given on the current status of solar and stellar dynamos. At present, it is still unclear why stellar cycle frequencies increase with rotation frequency in such a way that their ratio increases with stellar activity. The…

Solar and Stellar Astrophysics · Physics 2015-06-15 Axel Brandenburg

Using direct simulations of hydromagnetic turbulence driven by random polarized waves it is shown that dynamo action is possible over a wide range of magnetic Prandtl numbers from 10^-3 to 1. Triply periodic boundary conditions are being…

Astrophysics · Physics 2010-01-15 Axel Brandenburg