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We discuss the problem of the formation of a large-scale magnetic field in the accretion disks around black holes, taking into account the non-uniform vertical structure of the disk. The high electrical conductivity of the outer layers of…

High Energy Astrophysical Phenomena · Physics 2012-08-07 G. S. Bisnovatyi-Kogan , A. S. Klepnev , R. V. E. Lovelace

In this paper we focus on the construction of stellar outflow models emerging from a polar coronal hole-type region surrounded by a magnetosphere in the equatorial regions during phases of quiescent accretion. The models are based on…

Solar and Stellar Astrophysics · Physics 2016-02-26 P. Todorov , T. Matsakos , V. Cayatte , C. Sauty , J. J. G. Lima , K. Tsinganos

Outflows are inevitably driven from the disk if the vertical component of the black hole (BH) gravity cannot resist the radiation force. We derive the mass loss rate in the outflows by solving a dynamical equation for the vertical gas…

High Energy Astrophysical Phenomena · Physics 2022-09-21 Xinwu Cao , Wei-Min Gu

We study the radiatively driven fluid jets around a non-rotating black hole. The radiation arising from the inner compact corona and outer sub-Keplerian part of the disc accelerates the jets. We obtain the steady state, semi-analytical,…

High Energy Astrophysical Phenomena · Physics 2021-11-17 RajKishor Joshi , Indranil Chattopadhyay , Lallan Yadav

Super-Eddington accretion discs with 3 and 15 dot M_E around black holes with mass 10 M_sun are examined by two-dimensional radiation hydrodynamical calculations extending from the inner disc edge to 5*10^4 r_g and lasting up to \sim 10^6…

Astrophysics · Physics 2009-11-10 T. Okuda , V. Teresi , E. Toscano , D. Molteni

Using axisymmetric MHD simulations we investigate how the overall jet formation is affected by a variation in the disk magnetic flux profile and/or the existence of a central stellar magnetosphere. Our simulations evolve from an initial,…

Astrophysics · Physics 2015-05-13 Christian Fendt

Outflows, spanning a wide range of dynamical properties and spatial extensions, have now been associated with a variety of accreting astrophysical objects, from supermassive black holes at the core of active galaxies to young stellar…

Astrophysics of Galaxies · Physics 2020-12-02 C. Ceccobello , M. H. M. Heemskerk , Y. Cavecchi , W. H. T. Vlemmings , D. Tafoya

We investigate the differences between an outflow in a highly-resistive accretion disk corona, and the results with smaller or vanishing resistivity. For the first time, we determine conditions at the base of a two-dimensional radially…

Solar and Stellar Astrophysics · Physics 2015-06-19 Miljenko Čemeljić , Nektarios Vlahakis , Kanaris Tsinganos

We discuss recent progress in understanding the launching of outflows/jets from the disc-magnetosphere boundary of slowly and rapidly rotating magnetized stars. In most of the discussed models the interior of the disc is assumed to have a…

Solar and Stellar Astrophysics · Physics 2013-06-06 R. V. E. Lovelace , M. M. Romanova , P. Lii

Axisymmetric magnetohydrodynamic (MHD) simulations have been applied to investigate the interrelation of a central stellar magnetosphere and stellar wind with a surrounding magnetized disk outflow and how the overall formation of a large…

Astrophysics · Physics 2011-02-11 Christian Fendt

We discuss the importance of large scale strong magnetic field in the removal of angular momentum outward, as well as the possible origin of different kinds of magnetic barrier in advective, geometrically thick, sub-Keplerian accretion…

High Energy Astrophysical Phenomena · Physics 2018-02-28 Tushar Mondal , Banibrata Mukhopadhyay

We discuss the problem of the formation of a large-scale magnetic field in the accretion disks around black holes, taking into account the nonuniform vertical structure of the disk. The high electrical conductivity of the outer layers of…

High Energy Astrophysical Phenomena · Physics 2011-04-27 G. S. Bisnovatyi-Kogan , R. V. E. Lovelace

Because the magneto-rotational instability is capable of exponentially amplifying weak preexisting magnetic fields, it might be hoped that the character of the magnetic field in accretion disks is independent of the nature of the seed…

Astrophysics · Physics 2009-11-13 Kris Beckwith , John F. Hawley , Julian H. Krolik

Jets and outflows are observed around a wide variety of accreting objects and seem to be a near-ubiquitous feature of accretion disks. Large-scale magnetic fields are thought to be necessary for jet formation in many systems, but a…

Astrophysics · Physics 2009-06-23 David M. Rothstein , Richard V. E. Lovelace

Numerical simulations with self-similar initial and boundary conditions provide a link between theoretical and numerical investigations of jet dynamics. We perform axisymmetric resistive magnetohydrodynamic (MHD) simulations for a…

Astrophysics · Physics 2009-11-13 Miljenko Cemeljic , Jose Gracia , Nektarios Vlahakis , Kanaris Tsinganos

We study ejection mechanisms for two kinds of steady jets: one observed from black hole binaries in the low/hard state and the other from SS433. The specific energy of the ejected gas is required to be positive for the jets to get to…

High Energy Astrophysical Phenomena · Physics 2022-10-21 Hajime Inoue

Aims: We consider cold self-similar magnetohydrodynamic (MHD) disc wind solutions to describe jets that are launched from the circumcompanion accretion discs in post-AGB binaries. Resulting predictions are matched to observations for five…

There is a broad consensus that accretion onto supermassive black holes and consequent jet formation power the observed emission from active galactic nuclei (AGNs). However, there has been less agreement about how jets form in accretion…

High Energy Astrophysical Phenomena · Physics 2021-01-25 Shane W. Davis , Alexander Tchekhovskoy

We summarize results from a survey of radiation-dominated black hole accretion flows across a wide range of mass accretion rates, as well as two values of black hole spin and initial magnetic field geometry. These models apply an algorithm…

High Energy Astrophysical Phenomena · Physics 2025-09-16 Lizhong Zhang , James M. Stone , Patrick D. Mullen , Shane W. Davis , Yan-Fei Jiang , Christopher J. White

We present results from axisymmetric, time-dependent hydrodynamical (HD) and magnetohydrodynamical (MHD) simulations of a gaseous envelope collapsing onto a black hole (BH). We consider gas with so small angular momentum that after an…

Astrophysics · Physics 2009-11-10 Daniel Proga