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Magnetic fields are a dynamically important agent for regulating structure formation in the interstellar medium. The study of the relative orientation between the local magnetic field and gas (column-) density gradient has become a powerful…

Astrophysics of Galaxies · Physics 2020-10-14 Bastian Körtgen , Juan D. Soler

(abridged) Photometry and long-slit spectroscopy are presented for a sample of 6 galaxies with a low surface brightness stellar disc and a bulge. The stellar and ionised-gas kinematics were measured along the major and minor axis in half of…

Magnetic fields are an elemental part of the interstellar medium in galaxies. However, their impact on gas dynamics and star formation in galaxies remains controversial. We use a suite of global magnetohydrodynamical simulations of isolated…

Astrophysics of Galaxies · Physics 2019-09-25 Bastian Körtgen , Robi Banerjee , Ralph E. Pudritz , Wolfram Schmidt

Magnetic fields are an important ingredient of the interstellar medium (ISM). Besides their importance for star formation, they govern the transport of cosmic rays, relevant to the launch and regulation of galactic outflows and winds, which…

Galaxies are observed to obey a strict set of dynamical scaling relations. We review these relations for rotationally supported disk galaxies spanning many decades in mass, surface brightness, and gas content. The behavior of these widely…

Astrophysics of Galaxies · Physics 2020-05-20 Stacy McGaugh , Federico Lelli , Pengfei Li , Jim Schombert

Using a high-resolution simulation of a dwarf galaxy, we quantify the energetic importance of magnetic fields within the different phases of its interstellar medium (ISM) on parsec scales. We show that, whilst overall the magnetic field is…

Astrophysics of Galaxies · Physics 2025-12-05 Ryan McGuiness , Rowan J. Smith , David Whitworth

The turbulent dynamics of nearby and extragalactic gas structures can be studied with the column density power spectrum, which is often described by a broken power-law.In an extragalactic context, the breaks in the power spectra have been…

Astrophysics of Galaxies · Physics 2021-06-09 Bastian Körtgen , Nickolas Pingel , Nicholas Killerby-Smith

The diffuse ionized gas (DIG) is an important component of the interstellar medium that can provide insights into the different physical processes affecting the gas in galaxies. We utilise optical IFU observations of 71 gas-stripped and…

We studied roles of the magnetic field on the gas dynamics in the Galactic bulge by a three-dimensional global magnetohydrodynamical simulation data, particularly focusing on vertical flows that are ubiquitously excited by magnetic…

Astrophysics of Galaxies · Physics 2018-03-28 Kensuke Kakiuchi , Takeru K. Suzuki , Yasuo Fukui , Kazufumi Torii , Rei Enokiya , Mami Machida , Ryoji Matsumoto

Aims: The aim of this work is to verify whether turbulent magnetic reconnection can provide the additional energy input required to explain the up to now only poorly understood ionization mechanism of the diffuse ionized gas (DIG) in…

Astrophysics of Galaxies · Physics 2015-06-05 T. L. Hoffmann , S. Lieb , A. W. A. Pauldrach , H. Lesch , P. J. N. Hultzsch , G. T. Birk

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

Magnetic fields pervade the entire Universe and affect the formation and evolution of astrophysical systems from cosmological to planetary scales. The generation and dynamical amplification of extragalactic magnetic fields through cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-27 F. Rincon , F. Califano , A. A. Schekochihin , F. Valentini

We consider a recently discovered class of instabilities, driven by cosmic ray streaming, in a variety of environments. We show that although these instabilities have been discussed primarily in the context of supernova driven interstellar…

Astrophysics of Galaxies · Physics 2014-11-20 Ellen G. Zweibel , John E. Everett

The role of magnetic helicity in astrophysical large-scale dynamos is reviewed and compared with cases where there is no energy supply and an initial magnetic field can only decay. In both cases magnetic energy tends to get redistributed to…

Solar and Stellar Astrophysics · Physics 2009-11-13 Axel Brandenburg

Small-scale turbulent dynamo is responsible for the amplification of magnetic fields on scales smaller than the driving scale of turbulence in diverse astrophysical media. Most earlier dynamo theories concern the kinematic regime and…

Astrophysics of Galaxies · Physics 2021-06-25 Siyao Xu , Alex Lazarian

Observations in polarized emission reveal the existence of large-scale coherent magnetic fields in a wide range of spiral galaxies. Radio-polarization data show that these fields are strongly inclined towards the radial direction, with…

Astrophysics · Physics 2009-11-13 Oliver Gressel , Udo Ziegler , Detlef Elstner , Günther Rüdiger

Stellar feedback is an essential step in the baryon cycle of galaxies, but it remains unconstrained beyond Cosmic Noon. We study the ionized gas kinematics, dynamical mass and gas-flow properties of a sample of 16 sub-$L^{\star}$…

Noncircular motions have been observed across various spatial scales in disk galaxies, yet the physical properties of the gas involved in these motions remain poorly constrained. Using data from 19 galaxies from the PHANGS-MUSE sample, we…

The study of dynamo action in astrophysical objects classically involves two timescales: the slow diffusive one and the fast advective one. We investigate the possibility of field amplification on an intermediate timescale associated with…

Classical Physics · Physics 2009-11-13 Emmanuel Dormy , David Gerard-Varet

Dwarf galaxies are ideal laboratories to test dark matter models and alternative theories because their dynamical mass (from observed kinematics) largely outweighs their baryonic mass (from gas and stars). In most star-forming dwarfs, cold…

Astrophysics of Galaxies · Physics 2022-01-31 Federico Lelli