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Related papers: Thin accretion disc with a corona in a central mag…

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I review our current theoretical understanding of the different possible rotating modes of accretion onto a black hole. I discuss both thick adiabatic flows and radiatively efficient thin disc solutions. I present a new self-consistent…

Astrophysics · Physics 2007-05-23 A. Merloni

X-ray observations of the tidal disruption event (TDE) candidate AT 2019avd show drastic variabilities in flux and spectral shape over hundreds of days, providing clues on the accretion disc-corona evolution. We utilize a disc-corona model,…

High Energy Astrophysical Phenomena · Physics 2026-03-27 Haichao Xu , Xinwu Cao , Yanan Wang , Andrzej A. Zdziarski

We use three-dimensional magnetohydrodynamical (MHD) simulations to study the formation of a corona above an initially weakly magnetized, isothermal accretion disk. We also describe a modification to time-explicit numerical algorithms for…

Astrophysics · Physics 2009-10-31 K. A. Miller , J. M. Stone

We study vertical structure of radiation pressure dominated disc with a hot corona. We include all the relevant processes like bound--free opacity and convection. We show that the presence of the corona modifies considerably the density and…

Astrophysics · Physics 2015-06-24 A. Różańska , B. Czerny , P. T. Życki , G. Pojmański

We formulate a general, steady-state model for the torque on a magnetized star from a surrounding accretion disc. For the first time, we include the opening of dipolar magnetic field lines due to the differential rotation between the star…

Astrophysics · Physics 2009-11-10 Sean Matt , Ralph E. Pudritz

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 apply a model of magnetically dominated coronae above standard accretion discs to the low/hard state of galactic black holes. When the disc-corona coupling is accounted for self-consistently assuming that magneto-rotational instability…

Astrophysics · Physics 2007-05-23 A. Merloni

We investigate the evolution of a thin viscous disc surrounding magnetic star, including the spindown of the star by the magnetic torques it exerts on the disc. The transition from an accreting to a non-accreting state, and the change of…

High Energy Astrophysical Phenomena · Physics 2015-05-27 Caroline D'Angelo , Henk Spruit

The spectral energy distributions of galactic black holes in the low/hard state and of low-luminosity AGN possess many common features, the most prominent being: compact, flat (or inverted) spectrum radio cores with high brightness…

Astrophysics · Physics 2009-09-17 A. Merloni , A. C. Fabian

We present a model for a corona above a geometrically thin standard disk around a black hole. This corona is fed by matter from the thin disk which evaporates from the cool layers underneath. An equilibrium establishes between the cool…

Astrophysics · Physics 2007-05-23 Friedrich Meyer , Bifang Liu , Emmi Meyer-Hofmeister

We propose a model of magnetic connection (MC) of a black hole with its surrounding accretion disc based on large-scale magnetic field. The MC gives rise to transport of energy and angular momentum between the black hole and the disc, and…

High Energy Astrophysical Phenomena · Physics 2009-11-13 Zhao-Ming Gan , Ding-Xiong Wang , Wei-Hua Lei

The structure of accretion curtain flows arising from magnetically disrupted discs is considered. It is shown that a sub-Alfvenic, magnetically channelled flow is consistent with matching the magnetic field across the curtain base. It is…

Solar and Stellar Astrophysics · Physics 2015-05-30 C. G. Campbell

We present a detailed calculation of the mechanism by which the Accretion-Ejection Instability can extract accretion energy and angular momentum from a magnetized disk, and redirect them to its corona. In a disk threaded by a poloidal…

Astrophysics · Physics 2009-11-07 Peggy Varniere , Michel Tagger

I show in this paper that two types of magnetic torques can appear in the interaction between an accretion disc and a magnetic accretor. There is the well-known torque resulting from the difference in angular velocity between the accretion…

Astrophysics · Physics 2009-10-30 Ulf Torkelsson

The vertical structure of optically thick accretion disks is investigated in the two-zone approximation. The disk is divided into an underlying disk and a corona, where the latter is defined as the upper surface layers for which the…

Astrophysics · Physics 2009-11-07 Ranjeev Misra , R. E. Taam

To estimate the feasibility of dense-matter phase transition, we studied the evolution of the central density as well as the baryon chemical potential of accreting neutron stars. We compared the thin-disk accretion with and without the…

High Energy Astrophysical Phenomena · Physics 2011-12-13 M. Bejger , J. L. Zdunik , P. Haensel , M. Fortin

The problem of interaction of the rotating magnetic field, frozen to a star, with a thin well conducting accretion disk is solved exactly. It is shown that a disk pushes the magnetic field lines towards a star, compressing the stellar…

Astrophysics of Galaxies · Physics 2015-06-12 Ya. N. Istomin , P. Haensel

We present a time-dependent model of the interaction between a neutron star magnetosphere and a thin (Shakura-Sunyaev) accretion disc, where the extent of the magnetosphere is determined by balancing outward diffusion and inward advection…

Astrophysics · Physics 2008-06-04 J. T. Locsei , A. Melatos

We develop a two-flow model of accretion onto a black hole which incorporates the effect of the local magneto-rotational instability. The flow consists of an accretion disk and an accreting corona, and the local dynamo affects the…

Astrophysics · Physics 2009-11-13 A. Janiuk , B. Czerny

It is believed that the hard X-ray emission in the luminous active galactic nuclei (AGNs) is from the hot corona above the cool accretion disk. However, the formation of the corona is still debated. Liu et al. investigated the spectrum of…

High Energy Astrophysical Phenomena · Physics 2016-12-14 J. Y. Liu , ErLin Qiao , B. F. Liu