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Fast and slow magnetosonic shock formation is presented for stationary and axisymmetric magnetohydrodynamical (MHD) accretion flows onto a black hole. The shocked black hole accretion solution must pass through magnetosonic points at some…

Astrophysics · Physics 2009-11-13 M. Takahashi , J. Goto , K. Fukumura , D. Rilett , S. Tsuruta

It is commonly believed that the optical/UV and X-ray emissions in luminous AGN are produced in an accretion disk and an embedded hot corona respectively. The inverse Compton scattering of disk photons by hot electrons in the corona can…

High Energy Astrophysical Phenomena · Physics 2015-05-05 B. F. Liu , R. E. Taam , E. Qiao , W. Yuan

We theoretically investigate the magnetic flux transport in geometrically thick accretion discs which may form around black holes. We utilize a two-dimensional (2D) kinematic mean-field model for poloidal field transport which is governed…

High Energy Astrophysical Phenomena · Physics 2023-10-02 Ryoya Yamamoto , Shinsuke Takasao

Previous MHD simulations have shown that wind must exist in black hole hot accretion flows. In this paper, we continue our study by investigating the detailed properties of wind, such as mass flux and poloidal speed, and the mechanism of…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Feng Yuan , Zhaoming Gan , Ramesh Narayan , Aleksander Sadowski , Defu Bu , Xue-Ning Bai

We investigate how magnetically driven outflows are powered by a rotating, weakly magnetized accretion flow onto a supermassive black hole using axisymmetric magnetohydrodynamic simulations. Our proposed model focuses on the accretion…

Astrophysics of Galaxies · Physics 2022-02-16 Shinsuke Takasao , Yuri Shuto , Keiichi Wada

The existence of outflow in accretion flows is confirmed by observations and magnetohydrodynamics (MHD) simulations. In this paper, we study outflows of accretion flows in the presence of resistivity and toroidal magnetic field. The…

High Energy Astrophysical Phenomena · Physics 2012-05-11 Kazem Faghei , Azam Mollatayefeh

Combined influence of rotation of a black hole and ambient magnetic fields creates conditions for powerful astrophysical processes of accretion and outflow of matter which are observed in many systems across the range of masses; from…

High Energy Astrophysical Phenomena · Physics 2023-07-26 Ondrej Kopacek , Vladimir Karas

We perform non-hydrodynamical 2.5D simulations to study the dynamics of material above accretion disk based on the disk radiation pressure acting on dust. We assume a super-accreting underlying disk with the accretion rate of 10 times the…

Astrophysics of Galaxies · Physics 2022-09-21 Mohammad-Hassan Naddaf , Bożena Czerny , Michal Zajaček

We present a detailed three dimensional magnetohydrodynamic (MHD) simulation describing the inner region of a disk accreting onto a black hole. To avoid the technical complications of general relativity, the dynamics are treated in…

Astrophysics · Physics 2009-10-31 John F. Hawley , Julian H. Krolik

We perform two-dimensional hydrodynamic simulations to study the non-rotating gas flow in the region from 1-1000 parsec. This region connects the galaxy scale and the accretion disk scale. The gas is irradiated by the photons generated by…

High Energy Astrophysical Phenomena · Physics 2020-07-01 De-Fu Bu , Xiao-Hong Yang , Bocheng Zhu

An accretion scenario in which the material captured by a black hole from its environment is assumed to be magnetized (\beta ~ 1) is discussed. We show that the accretion picture in this case is strongly affected by the magnetic field of…

High Energy Astrophysical Phenomena · Physics 2012-11-20 N. R. Ikhsanov , L. A. Pustil'nik , N. G. Beskrovnaya

We perform GR-MHD simulations of outflow launching from thin accretion disks. As in the non-relativistic case, resistivity is essential for the mass loading of the disk wind. We implemented resistivity in the ideal GR-MHD code HARM3D,…

High Energy Astrophysical Phenomena · Physics 2019-09-04 Christos Vourellis , Christian Fendt , Qian Qian , Scott Noble

We run three long-timescale general-relativistic magnetohydrodynamic simulations of radiatively inefficient accretion flows onto non-rotating black holes. Our aim is to achieve steady-state behavior out to large radii and understand the…

High Energy Astrophysical Phenomena · Physics 2020-03-11 Christopher J. White , Eliot Quataert , Charles F. Gammie

Black hole (BH) accretion flows and jets are qualitatively affected by the presence of ordered magnetic fields. We study fully three-dimensional global general relativistic magnetohydrodynamic (MHD) simulations of radially extended and…

High Energy Astrophysical Phenomena · Physics 2015-06-03 Jonathan C. McKinney , Alexander Tchekhovskoy , Roger D. Blandford

We investigate numerical convergence in simulations of magnetically arrested disks around spinning black holes. Using the general-relativistic magnetohydrodynamics code Athena++, we study the same system at four resolutions (up to an…

High Energy Astrophysical Phenomena · Physics 2019-06-25 Christopher J. White , James M. Stone , Eliot Quataert

A toy model of a disk undergoing steady state accretion onto a black hole is presented. The disk is in a hydrostatic equilibrium for all radii r > r_{in}, with the inner disk radius located between the marginally stable and marginally bound…

Astrophysics · Physics 2007-05-23 Bohdan Paczynski

Accretion flows onto underluminous black holes, such as Sagittarius A* at the center of our galaxy, are dilute (mildly collisional to highly collisionless), optically thin, and radiatively inefficient. Therefore, the accretion properties of…

High Energy Astrophysical Phenomena · Physics 2015-05-28 Tanim Islam

Astrophysical accretion is arguably the most prevalent physical process in the Universe; it occurs during the birth and death of individual stars and plays a pivotal role in the evolution of entire galaxies. Accretion onto a black hole, in…

High Energy Astrophysical Phenomena · Physics 2009-12-09 Peter B. Dobbie , Zdenka Kuncic , Geoffrey V. Bicknell , Raquel Salmeron

We extend the work by Appl and Camenzind (1988) for special relativistic magnetohydrodynamic (MHD) jets, to fully general relativistic studies of the standing shock formation for accreting MHD plasma in a rotating, stationary and…

Astrophysics · Physics 2009-11-07 Masaaki Takahashi , Darrell Rilett , Keigo Fukumura , Sachiko Tsuruta

By performing two-dimensional axisymmetric general relativistic radiation magnetohydrodynamics simulations with spin parameter $a^*$ varying from -0.9 to 0.9, we investigate the dependence on the black hole spin of the energy flow from…

High Energy Astrophysical Phenomena · Physics 2022-08-17 Aoto Utsumi , Ken Ohsuga , Hiroyuki R. Takahashi , Yuta Asahina
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