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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 consider stationary, axisymmetric hydrodynamic accretion flows in Kerr geometry. As a plausible means of efficiently separating a small population of nonthermal particles from the bulk accretion flows, we investigate the formation of…

Astrophysics · Physics 2009-11-13 Keigo Fukumura , Demosthenes Kazanas

In this third study of the 'Resolving supermAssive Black hole Binaries In galacTic hydrodynamical Simulations' (RABBITS) series we develop and implement a geometrically thin relativistic accretion disc model, which self-consistently evolves…

Recent numerical simulations of radiatively inefficient accretion flows onto compact objects have shown that convection is a general feature in such flows. Dissipation of rotational and gravitational energies in the accretion flows results…

Astrophysics · Physics 2009-11-06 Igor V. Igumenshchev , Marek A. Abramowicz

There is a very popular two-zone accretion disk model that the inner part of the non-advective Keplerian disk (Shakura-Sunyaev disk) can produce hot advection-dominated accretion flow, which can generate high energy power-law radiation and…

High Energy Astrophysical Phenomena · Physics 2022-10-04 Rajiv Kumar , Ye-Fei Yuan

Hydrodynamics and magnetohydrodynamic simulations of hot accretion flow have indicated that there is an inward decreasing of mass accretion rate with decreasing radius. Consequently, we have a flatter density profile ($\rho \propto r^{-p}$…

High Energy Astrophysical Phenomena · Physics 2017-06-12 Maryam Ghasemnezhad

In recent past, the progresses in accretion studies onto relativistically gravitating central objects like a Schwarzschild singularity reveal that the accretion flow must be transonic. For such cases, the radial inward speed gradient can be…

General Relativity and Quantum Cosmology · Physics 2020-03-18 Parthajit Roy , Ritabrata Biswas

We consider an accretion flow model originally proposed by Bisnovatyi-Kogan & Ruzmaikin (1974), which has been confirmed in recent 3D MHD simulations. In the model, the accreting gas drags in a strong poloidal magnetic field to the center…

Astrophysics · Physics 2015-06-24 Ramesh Narayan , Igor V. Igumenshchev , Marek A. Abramowicz

One of the greatest issues in modelling black hole fuelling is our lack of understanding of the processes by which gas loses angular momentum and falls from galactic scales down to the nuclear region where an accretion disc forms,…

Astrophysics of Galaxies · Physics 2013-12-24 Juan Manuel Carmona-Loaiza , Monica Colpi , Massimo Dotti , Riccardo Valdarnini

This paper investigates the dynamical behavior of steady spherical accretion onto a static, magnetically charged black hole embedded in a perfect fluid dark matter (PFDM) background. Using the shadow observations of M87* from the Event…

High Energy Astrophysical Phenomena · Physics 2026-03-11 Taiyang Zhang , Zhongyuan Qin , Qian Feng , Zheng-Wen Long

We characterize the nature of thin, axisymmetric, inviscid, accretion flows of cold adiabatic gas with zero specific energy in the vicinity of a black hole by the specific angular momentum. Using two-dimensional hydrodynamic simulations in…

Astrophysics · Physics 2009-10-28 Dongsu Ryu , Sandip K. Chakrabarti , Diego Molteni

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

This work presents a detailed analysis of the overall flow structure and unique features of the inner region of the tilted disk simulations described in Fragile et al. (2007). The primary new feature identified in the main disk body is a…

Astrophysics · Physics 2009-11-13 P. Chris Fragile , Omer M. Blaes

The hydrodynamic behaviour of perfect fluid orbiting around black holes in spherically symmetric spacetime for various alternative gravity theories has been investigated. For this purpose we have assumed an uniform distribution for the…

General Relativity and Quantum Cosmology · Physics 2015-03-11 Sumanta Chakraborty

We numerically construct slim, global, vertically integrated models of optically thin, transonic accretion discs around black holes, assuming a regularity condition at the sonic radius and boundary conditions at the outer radius of the disc…

Astrophysics · Physics 2009-10-30 I. V. Igumenshchev , M. A. Abramowicz , I. D. Novikov

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

We use global three dimensional radiation magneto-hydrodynamical simulations to study accretion disks onto a $5\times 10^8M_{\odot}$ black hole with accretion rates varying from $\sim 250L_{Edd}/c^2$ to $1500 L_{Edd}/c^2$. We form the disks…

High Energy Astrophysical Phenomena · Physics 2019-09-11 Yan-Fei Jiang , James Stone , Shane W. Davis

We study a truncated accretion disk using a well-resolved, semi-global magnetohydrodynamic simulation that is evolved for many dynamical times (6096 inner disk orbits). The spectral properties of hard state black hole binary systems and…

High Energy Astrophysical Phenomena · Physics 2018-04-25 J. Drew Hogg , Christopher S. Reynolds

We study the long-term evolution of the global structure of axisymmetric accretion flows onto a black hole (BH) at rates substantially higher than the Eddington value ($\dot{M}_{\rm Edd}$), performing two-dimensional hydrodynamical…

High Energy Astrophysical Phenomena · Physics 2022-09-01 Haojie Hu , Kohei Inayoshi , Zoltán Haiman , Eliot Quataert , Rolf Kuiper

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