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Related papers: Magnetic flux stabilizing thin accretion disks

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We investigate the generation of magnetic fields above black hole accretion discs due to the non-zero curl of the disc radiation field. By self consistently computing the components of the radiation flux and their curl, we show that the…

High Energy Astrophysical Phenomena · Physics 2025-05-16 Mukesh Kumar Vyas , Asaf Pe'er

We present an extension of the King et al. (2004) model for the flickering of black hole accretion discs by taking proper account for the thermal properties of the disc. First we develop a one-dimensional, vertically averaged, one-zone…

Astrophysics · Physics 2008-11-26 M. Mayer , J. E. Pringle

Radio continuum observations of barred galaxies revealed strong magnetic fields of >= 50-100 muG in the circumnuclear starbursts. Such fields are dynamically important and give rise to magnetic stress that causes inflow of gas towards the…

Astrophysics of Galaxies · Physics 2015-06-03 Rainer Beck

We study the energetics of a black hole-accretion disk system with magnetic connection: a Keplerian disk is connected to a Kerr black hole by a large-scale magnetic field going through the transition region. We assume that the magnetic…

Astrophysics · Physics 2015-06-24 Li-Xin Li

Cold steady-state disk wind theory from near Keplerian accretion disks requires a large scale magnetic field at near equipartition strength. However the minimum magnetization has never been tested. We investigate the time evolution of an…

Solar and Stellar Astrophysics · Physics 2015-03-13 Gareth C. Murphy , Jonathan Ferreira , Claudio Zanni

We study how axisymmetric magnetohydrodynamical (MHD) accretion flows depend on gamma adiabatic index in the polytropic equation of state. This work is an extension of Moscibrodzka & Proga (2008), where we investigated the gamma dependence…

High Energy Astrophysical Phenomena · Physics 2015-05-13 Monika Moscibrodzka , Daniel Proga

We investigate the stability properties of a hot, dilute and differentially rotating weakly magnetized plasma which is believed to be found in the interstellar medium of galaxies and protogalaxies and in the low-density accretion flows…

Astrophysics of Galaxies · Physics 2015-05-18 Ebru Devlen , E. Rennan Pekünlü

We explore the effects of anisotropic thermal conduction, anisotropic pressure, and magnetic field strength on the hot accretion flows around black holes by solving the axisymmetric, steady-state magnetohydrodynamic equations. The…

High Energy Astrophysical Phenomena · Physics 2022-03-09 Amin Mosallanezhad , Fatemeh Zahra Zeraatgari , Liquan Mei , De-Fu Bu

(Abridged) We report results of three dimensional MHD simulations of global accretion disks threaded with weak vertical magnetic fields. We perform the simulations in the spherical coordinates with different temperature profiles and…

Earth and Planetary Astrophysics · Physics 2015-06-17 Takeru K. Suzuki , Shu-ichiro Inutsuka

We perform axisymmetric, two-dimensional magnetohydrodynamic (MHD) simulations to investigate accretion flows around spinning AGN. To mimic the space-time geometry of spinning black holes, we consider effective Kerr potential, and the mass…

High Energy Astrophysical Phenomena · Physics 2023-10-25 Ramiz Aktar , Kuo-Chuan Pan , Toru Okuda

There is observational evidence that the X-ray continuum source that creates the broad fluorescent emission lines in some Seyfert Galaxies may be compact and located at a few gravitational radii above the black hole. We consider the…

High Energy Astrophysical Phenomena · Physics 2019-02-05 Yajie Yuan , Roger D. Blandford , Dan R. Wilkins

Recent work on the structure of magnetic fields in a turbulent medium gives predictions for the properties of the magnetic flux tubes as a function of the Mach number and scale of the turbulence, and the resistivity and viscosity of the…

Astrophysics · Physics 2010-04-23 Ethan T. Vishniac

We report results from calculations investigating stationary magnetic field configurations in accretion discs around magnetised neutron stars. Our strategy is to start with a very simple model and then progressively improve it providing…

Solar and Stellar Astrophysics · Physics 2014-11-20 L. Naso , J. C. Miller

We briefly review recent developments in black hole accretion disk theory, placing new emphasis on the vital role played by magnetohydrodynamic (MHD) stresses in transporting angular momentum. The apparent universality of accretion-related…

Astrophysics · Physics 2009-06-23 Zdenka Kuncic , Geoffrey V. Bicknell

Based on the model of the accretion-induced magnetic field decay of a neutron star (NS), millisecond pulsars (MSPs) will obtain their minimum magnetic field when the NS magnetosphere radius shrinks to the stellar surface during the binary…

High Energy Astrophysical Phenomena · Physics 2018-08-03 Y. Y. Pan , C. M. Zhang , L. M. Song , N. Wang , D. Li , Y. Y. Yang

We reconsider the problem of the formation of a large-scale magnetic field in the accretion disks around black holes. In contrast with previous work we take into account the nonuniform vertical structure of the disk. The high electrical…

Astrophysics · Physics 2009-11-13 G. S. Bisnovatyi-Kogan , R. V. E. Lovelace

We examine mass outflows from a low-angular momentum, viscous, advective, and magnetized accretion disk around a rotating black hole in presence of thermal conduction. We consider the disk is primarily threaded by the toroidal component of…

High Energy Astrophysical Phenomena · Physics 2025-09-15 Camelia Jana , Monu Singh , Suvendu Rakshit , Santabrata Das

Some of the accreting black holes exhibit much stronger variability patterns than the usual stochastic variations. Radiation pressure instability is one of the proposed mechanisms which could account for this effect. We aim to model…

High Energy Astrophysical Phenomena · Physics 2023-03-29 Marzena Śniegowska , Mikołaj Grzędzielski , Bożena Czerny , Agnieszka Janiuk

We use three dimensional magnetohydrodynamic simulations to study the structure of the boundary layer between an accretion disc and a non-rotating, unmagnetized star. Under the assumption that cooling is efficient, we obtain a narrow but…

Astrophysics · Physics 2009-11-07 Philip J. Armitage

We have succeeded in obtaining magnetized star models that have extremely strong magnetic fields in the interior of the star. In our formulation, arbitrary functions of the magnetic flux function appear in the expression for the current…

High Energy Astrophysical Phenomena · Physics 2013-04-03 Kotaro Fujisawa , Shin'ichirou Yoshida , Yoshiharu Eriguchi