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Related papers: Fast dynamos in weakly ionized gases

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Comparisons of the kinematics of Mg II absorbing gas and the stellar rotation curves in 0.5 < z < 1.0 spiral galaxies suggests that, at least in some cases, the extended gaseous envelopes may be dynamically coupled to the stellar matter. A…

Astrophysics · Physics 2016-01-27 Chris Churchill , Chuck Steidel

Dynamo action refers to energy exchange processes through which magnetic fields are generated at the expense of kinetic energy of the plasma flows. Dynamos can generate magnetic fields across scales larger or smaller than the flows…

We present the results of ionized gas turbulent motions study in several nearby dwarf galaxies using a scanning Fabry-Perot interferometer with the 6-m telescope of the SAO RAS. Combining the `intensity-velocity dispersion' diagrams…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Alexei Moiseev , Tatiana Lozinskaya

We present spatially-resolved measurements of the ionized gas masses and mass outflow rates for six low-redshift ($z \leq$ 0.02) active galaxies. In this study, we expand our sample to galaxies with more complex gas kinematics modeled as…

Arguably the main challenge of galactic magnetism studies is to explain how the interstellar medium of galaxies reaches energetic equipartition despite the extremely weak cosmic primordial magnetic fields that are originally predicted to…

Astrophysics of Galaxies · Physics 2018-06-20 Sergio Martin-Alvarez , Julien Devriendt , Adrianne Slyz , Romain Teyssier

Large-scale intergalactic magnetic fields may contain a mixture of galactic and cosmogenic contributions, that can be probed via observations of $\gamma$-ray "echo" - a delayed emission from electromagnetic cascades initiated by the highest…

High Energy Astrophysical Phenomena · Physics 2026-02-10 Ievgen Vovk

We review recent results on the nonlinear development of thermal instability in the context of the turbulent atomic interstellar medium (ISM). First, we pre- sent a brief summary of the linear theory, remarking that, in the atomic ISM, the…

Stellar feedback plays a fundamental role in shaping the evolution of galaxies. Here we explore the use of ionised gas kinematics in young, bipolar H II regions as a probe of early feedback in these star-forming environments. We have…

Convectively driven dynamos with rotation generating magnetic fields on scales large compared with the scale of the turbulent eddies are being reviewed. It is argued that such fields can be understood as the result of an alpha effect.…

Solar and Stellar Astrophysics · Physics 2011-08-19 A. Brandenburg , P. J. Käpylä , M. J. Korpi

The origin and evolution of magnetic fields in the Universe is still an open question. Their observations in galaxies suggest strong magnetic fields already at high redshift as well as at present time. However, neither primordial magnetic…

Astrophysics of Galaxies · Physics 2017-04-21 Michael Rieder , Romain Teyssier

Cosmic voids are magnetized at the level of at least $10^{-17}$ G on Mpc scales, as implied by blazar observations. We show that an electrically conducting plasma is present in the voids, and that, because of the plasma, \emph{diffusion}…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-21 Oindrila Ghosh , Axel Brandenburg , Chiara Caprini , Andrii Neronov , Franco Vazza

We introduce a potentially powerful method for constraining or discovering a thin dark matter disk in the Milky Way. The method relies on the relationship between the midplane densities and scale heights of interstellar gas being determined…

Astrophysics of Galaxies · Physics 2016-09-30 Eric David Kramer , Lisa Randall

The interstellar medium in star-forming galaxies is a multiphase gas in which turbulent support is at least as important as thermal pressure. Sustaining this configuration requires continuous radiative cooling, such that the overall average…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Evan Scannapieco , William J. Gray , Liubin Pan

A typical galactic disc has a finite thickness and in addition to stars it also contains a finite amount of interstellar gas. Here, we investigate the physical impact of the finite thickness of a galactic disc on the disc stability against…

Astrophysics of Galaxies · Physics 2022-03-14 Soumavo Ghosh , Chanda J. Jog

The origin of large-scale magnetic fields, detected in some low-mass (dwarf and irregular) galaxies via polarised synchrotron emission and Faraday rotation, remained unexplained for a long time. We suggest that mean-field dynamo can be…

Astrophysics of Galaxies · Physics 2019-10-16 Prasanta Bera , Anvar Shukurov , Kandaswamy Subramanian

Magnetic fields connect an array of planetary processes, from atmospheric escape to interior convection. Despite their importance, exoplanet magnetic fields are largely unconstrained by both theory and observation. In this Letter, we…

Earth and Planetary Astrophysics · Physics 2024-06-25 Arjun B. Savel , Hayley Beltz , Thaddeus D. Komacek , Shang-Min Tsai , Eliza M. -R. Kempton

Understanding the in situ amplification of large scale magnetic fields in turbulent astrophysical rotators has been a core subject of dynamo theory. When turbulent velocities are helical, large scale dynamos that substantially amplify…

Fluid Dynamics · Physics 2012-06-22 Jonathan Pietarila Graham , Eric G. Blackman , Pablo D. Mininni , Annick Pouquet

The role of magnetic fields in the multi-phase interstellar medium (ISM) is explored using magnetohydrodynamic (MHD) simulations that include energy injection by supernova (SN) explosions and allow for dynamo action. Apart from providing…

Astrophysics of Galaxies · Physics 2018-10-03 A. Shukurov , C. C. Evirgen , A. Fletcher , P. J. Bushby , F. A. Gent

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