English
Related papers

Related papers: A Model for Quasi-Spherical Magnetized Accretion F…

200 papers

The existence of outflow and magnetic field in the inner region of hot accretion flows have been confirmed by observations and numerical magnetohydrodynamic simulations (MHD). We present self-similar solutions for radiation inefficiently…

Astrophysics of Galaxies · Physics 2015-06-05 S. Abbassi , A. Mosallanezhad

Magnetically-arrested disks (MADs) appear when accretion flows are supplied with a sufficient amount of magnetic flux. In this work, we use results of magnetohydrodynamic simulations to set the configuration of the magnetic field and…

High Energy Astrophysical Phenomena · Physics 2020-01-31 Fu-Guo Xie , Andrzej A. Zdziarski

Accretion discs properties should deviate from standard theory when magnetic pressure exceeds the thermal pressure. To quantify these deviations, we present a systematic study of the dynamical properties of magnetically arrested discs…

High Energy Astrophysical Phenomena · Physics 2023-10-26 Nicolas Scepi , Mitchell C. Begelman , Jason Dexter

We report on the second phase of our study of slightly rotating accretion flows onto black holes. We consider magnetohydrodynamical (MHD) accretion flows with a spherically symmetric density distribution at the outer boundary, but with…

Astrophysics · Physics 2009-11-07 D. Proga , M. C. Begelman

We investigate the model of the disc/corona accretion flow around the black hole. The model, parameterized by the total (i.e. disk plus corona) accretion rate, $\dot m$, mass of the black hole, $M$ and the viscosity parameter, $\alpha$,…

Astrophysics · Physics 2007-05-23 A. Różańska , B. Czerny

In standard accretion discs, outward angular momentum transfer by viscous forces is compensated by the inward motion of the accreting matter. However, the vertical structure of real accretion discs leads to meridional circulation with…

High Energy Astrophysical Phenomena · Physics 2017-12-27 Pavel Abolmasov

We present the results from axisymmetric time-dependent HD calculations of gas flows which are under the influence of gravity of a black hole in quasars. We assume that the flows are non-rotating and exposed to quasar radiation. We take…

Astrophysics · Physics 2011-02-11 Daniel Proga

Observational evidence and theoretical arguments postulate that outflows may play a significant role in the advection-dominated accretion discs (ADAFs). While the azimuthal viscosity is the main focus of most previous studies in this…

High Energy Astrophysical Phenomena · Physics 2020-03-18 S. M. Ghoreyshi , M. Shadmehri

We present the global structure of magnetized advective accretion flow around the rotating black holes in presence of dissipation. By considering accretion flow to be threaded by toroidal magnetic fields and by assuming synchrotron…

High Energy Astrophysical Phenomena · Physics 2018-08-08 Santabrata Das , Biplob Sarkar

Accretion disks are three-dimensional, turbulent, often self-gravitating, magnetohydrodynamic flows, which can be modeled in detail with numerical simulations. In this paper, we present a new algorithm that is based on a spectral…

Astrophysics · Physics 2009-07-22 Chi-kwan Chan , Dimitrios Psaltis , Feryal Ozel

We present an analytic, quasi-local model for accretion discs threaded by net, vertical magnetic flux. In a simple slab geometry and ignoring stochastic mean-field dynamo effects, we calculate the large-scale field resulting from the…

High Energy Astrophysical Phenomena · Physics 2024-10-18 Mitchell C. Begelman

This paper explores the effects of large-scale magnetic fields in hot accretion flows for asymmetric configurations with respect to the equatorial plane. The solutions that we have found show that the large-scale asymmetric magnetic field…

High Energy Astrophysical Phenomena · Physics 2017-07-26 Maryam Samadi , Shahram Abbassi , Richard Lovelace

(Abridged) We present one of the first physically-motivated two-dimensional general relativistic magnetohydrodynamic (GRMHD) numerical simulations of a radiatively-cooled black-hole accretion disk. The fiducial simulation combines a…

Astrophysics · Physics 2011-02-11 P. Chris Fragile , David L. Meier

We present the effects of ordered large scale magnetic field on the structure of supercritical accretion flow in the presence of outflow. In the cylindrical coordinates ($r, \varphi,z$), We write the 1.5 dimensional, the steady state…

High Energy Astrophysical Phenomena · Physics 2017-06-21 Maryam Ghasemnezhad , Shahram Abbassi

Radiatively inefficient accretion flows onto black holes are unstable due to both an outwardly decreasing entropy (`convection') and an outwardly decreasing rotation rate (the `magnetorotational instability'; MRI). Using a linear…

Astrophysics · Physics 2009-11-07 Ramesh Narayan , Eliot Quataert , Igor V. Igumenshchev , Marek A. Abramowicz

Using a toy model of a two dimensional accretion disk, we discuss further the radial equation of the accretion flow dominated by the Poynting flux. Assuming the force-free condition is valid around the accretion disk, the relation between…

Astrophysics · Physics 2008-11-26 Hyun Kyu Lee

We explore the global structure of the accretion flow around a Schwarzschild black hole where the accretion disc is threaded by toroidal magnetic fields. The accretion flow is optically thin and advection dominated. Synchrotron radiation is…

High Energy Astrophysical Phenomena · Physics 2018-03-14 Biplob Sarkar , Santabrata Das

Advection is believed to be the dominant cooling mechanism in optically thin advection-dominated accretion flows (ADAF's). When outflow is considered, however, the first impression is that advection should be of opposite sign in the inflow…

High Energy Astrophysical Phenomena · Physics 2023-01-24 Cheng-Liang Jiao

We investigate the dynamical behaviour of a magnetized, dissipative, accretion flow around a rapidly rotating black hole. We solve the magnetohydrodynamic equations and calculate the transonic accretion solutions which may contain…

High Energy Astrophysical Phenomena · Physics 2020-04-15 Biplob Sarkar , Anjali Rao

We study low-density axisymmetric accretion flows onto black holes (BHs) with two-dimensional hydrodynamical simulations, adopting the $\alpha$-viscosity prescription. When the gas angular momentum is low enough to form a rotationally…

Astrophysics of Galaxies · Physics 2018-09-18 Kohei Inayoshi , Jeremiah P. Ostriker , Zoltan Haiman , Rolf Kuiper