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Related papers: Accretion Disk Models with Self-Consistent Advecti…

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We present self-similar solutions for advection -dominated accretion flows with thermal conduction in the presence of outflows. Possible effects of outflows on the accretion flow are parametrized and a saturated form of thermal conduction,…

Astrophysics · Physics 2009-11-13 Mohsen Shadmehri

We report on a new class of solutions of black hole accretion disks that we have found through three-dimensional, global, radiative magnetohydrodynamic simulations in general relativity. It combines features of the canonical thin, slim and…

The purpose of this paper is to explore the dynamical behaviour of hot accretion flow with thermal conduction. The importance of thermal conduction on hot accretion flow is confirmed by observations of the hot gas that surrounds Sgr A$^*$…

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

General properties of advection-dominated accretion flows are discussed. Special emphasis is given to the optically thin branch of solutions, which has very high ion and electron temperatures and is thermally stable. This solution branch…

Astrophysics · Physics 2007-05-23 Ramesh Narayan

Accretion disk outbursts, and their subsequent decline, offer a unique opportunity to constrain the physics of angular momentum transport in hot accretion disks. Recent work has centered on the claim by Cannizzo et al. that the exponential…

Astrophysics · Physics 2009-10-30 Ethan T. Vishniac

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

Accretion disk theory was first developed as a theory with the local heat balance, where the whole energy produced by a viscous heating was emitted to the sides of the disk. One of the most important new invention of this theory was the…

Astrophysics · Physics 2009-11-07 G. S. Bisnovatyi-Kogan , R. V. E. Lovelace

We describe new optically thin solutions for rotating accretion flows around black holes and neutron stars. These solutions are advection dominated, so that most of the viscously dissipated energy is advected radially with the flow. We…

Astrophysics · Physics 2009-10-22 Ramesh Narayan , Insu Yi

We review models which include advective accretion disks onto compact objects and discuss the influence of the centrifugal pressure supported high density region close to the compact objects on the emitted spectra. We show that the…

Astrophysics · Physics 2007-05-23 Sandip K. Chakrabarti

Models of black hole accretion disks are reviewed, with an emphasis on the theory of hard X-ray production. The following models are considered: i) standard, ii) super-critical, iii) two-temperature, and iv) disk+corona. New developments…

Astrophysics · Physics 2007-05-23 Andrei M. Beloborodov

In order to study the outflows from accretion disks, we solve the set of hydrodynamic equations for accretion disks in the spherical coordinates ($r\theta\phi$) to obtain the explicit structure along the $\theta$ direction. Using…

High Energy Astrophysical Phenomena · Physics 2011-05-25 Cheng-Liang Jiao , Xue-Bing Wu

We solve for the structure of a hot accretion disc with unsaturated thermal Comptonisation of soft photons and with advection, generalizing the classical model of Shapiro et al. The upper limit on the accretion rate due to advection…

Astrophysics · Physics 2015-06-24 Andrzej A. Zdziarski

We present global solutions of optically thin, two-temperature black hole accretion disks incorporating magnetic fields. We assume that the {\pi}{\phi}-component of the Maxwell stress is proportional to the total pressure, and prescribe the…

High Energy Astrophysical Phenomena · Physics 2015-05-30 Hiroshi Oda , Mami Machida , Kenji E. Nakamura , Ryoji Matsumoto , Ramesh Narayan

We obtained steady solutions of optically thin, single temperature, magnetized black hole accretion disks assuming thermal bremsstrahlung cooling. Based on the results of 3D MHD simulations of accretion disks, we assumed that the magnetic…

Astrophysics · Physics 2015-06-24 H. Oda , M. Machida , K. E. Nakamura , R. Matsumoto

We construct an analytical black hole accretion disk model that incorporates both magnetic pressure and disk wind, which are found to be important from numerical simulations. A saturated magnetic pressure that relates the Alfven velocity…

High Energy Astrophysical Phenomena · Physics 2023-09-11 Jiahui Huang , Hua Feng , Wei-Min Gu , Wen-Biao Wu

We investigated accretion on to black holes in presence of viscosity and cooling, by employing an equation of state with variable adiabatic index and multi-species fluid. We obtained the expression of generalized Bernoulli parameter which…

High Energy Astrophysical Phenomena · Physics 2015-06-22 Rajiv Kumar , Indranil Chattopadhyay

The standard equilibrium for radiation-dominated accretion disks has long been known to be viscously, thermally, and convectively unstable, but the nonlinear development of these instabilities---hence the actual state of such disks---has…

Astrophysics · Physics 2009-11-06 Eric Agol , Julian Krolik , Neal Turner , James Stone

Hot accretion flows such as advection-dominated accretion flows are generally optically thin in the radial direction. Thus photons generated at some radii can cool or heat electrons at other radii via Compton scattering. Such global Compton…

High Energy Astrophysical Phenomena · Physics 2012-07-16 Fu-Guo Xie , Andrzej Niedzwiecki , Andrzej A. Zdziarski , Feng Yuan

We consider non-local effects which arise when radiation emitted at one radius of an accretion disk either heats or cools gas at other radii through Compton scattering. We discuss three situations: 1. Radiation from the inner regions of an…

Astrophysics · Physics 2016-08-30 Ann A. Esin

Cold optically thick accretion disks with hot coronae and radial advection have been investigated. Within the framework of $\alpha$-viscosity models, we assume that all the mass accretion and angular momentum transport take place in the…

Astrophysics · Physics 2009-10-28 Xingming Chen