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We have studied the effects of thermal conduction on the structure of viscous and resistive advection-dominated accretion flows (ADAFs). The importance of thermal conduction on hot accretion flow is confirmed by observations of hot gas that…

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

We study the effects of optically thin radiative cooling on the structure of radiatively inefficient accretion flows (RIAFs). The flow structure is geometrically thick, and independent of the gas density and cooling, if the cooling time is…

High Energy Astrophysical Phenomena · Physics 2015-06-15 Upasana Das , Prateek Sharma

Nonlinear time-dependent calculations are being carried out in order to study the evolution of vertically-integrated models of non-selfgravitating, transonic accretion discs around black holes. In this paper we present results from a new…

Astrophysics · Physics 2009-10-30 Ewa Szuszkiewicz , John C. Miller

In dwarf nov{\ae} and low-mass X-ray binaries, the tidal potential excites spiral waves in the accretion disc. Spiral wave driven accretion may be important in quiescent discs, where the angular momentum transport mechanism has yet to be…

High Energy Astrophysical Phenomena · Physics 2023-08-30 M. Van den Bossche , G. Lesur , G. Dubus

The standard thin disk model predicts that when the accretion rate is over a small fraction of the Eddington rate, which corresponds to $L \ga 0.06 L_{Edd}$, the inner region of the disk is radiation-pressure-dominated and thermally…

High Energy Astrophysical Phenomena · Physics 2015-05-27 Sheng-Ming Zheng , Feng Yuan , Wei-Min Gu , Ju-Fu Lu

The boundary layers of weakly-magnetized white dwarfs (WDs) accreting at rates <=10^16 g/s are radially extended, hot, optically-thin, and they advect some of their internally-dissipated energy (Narayan & Popham 1993). Motivated by this, I…

Astrophysics · Physics 2007-05-23 Kristen Menou

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

The composition of forming planets is strongly affected by the protoplanetary disc's thermal structure. This thermal structure is predominantly set by dust radiative transfer and viscous (accretional) heating and can be impacted by gaps -…

Earth and Planetary Astrophysics · Physics 2023-09-18 Madelyn Broome , Oliver Shorttle , Mihkel Kama , Richard A. Booth

Accretion disc 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 disc. One of the most important new invention of this theory was a…

Astrophysics · Physics 2016-01-27 G. S. Bisnovatyi-Kogan

Transitional protostellar disks have inner cavities heavily depleted in dust and gas, yet most show signs of ongoing accretion, often at rates comparable to full disks. We show that recent constraints on the gas surface density in a few…

Earth and Planetary Astrophysics · Physics 2017-01-25 Lile Wang , Jeremy J. Goodman

In this paper we explore numerically the evolution of a warped accretion disc. Here, we focus here on the regime where the warp evolves diffusively. By comparing the numerical results to a simple diffusion model, we are able to determine…

Astrophysics · Physics 2009-11-13 Giuseppe Lodato , J. E. Pringle

The outburst cycles of black hole X-ray transients are now generally understood as caused by a thermal instability in the accretion disk, the same mechanism as in dwarf novae outbursts. During quiescence the accretion occurs via a cool disk…

Astrophysics · Physics 2009-11-06 Emmi Meyer-Hofmeister , Friedrich Meyer

Modelling the flow in a thin accretion disc like a dynamical system, we analyse the nature of the critical points of the steady solutions of the flow. For the simple inviscid disc there are two critical points, with the outer one being a…

Astrophysics · Physics 2007-05-23 Arnab K. Ray , J. K. Bhattacharjee

We investigate the role of radiative driving of shock ejected bipolar outflows from advective accretion discs in a self consistent manner. Radiations from the inner disc affects the subsonic part of the jet while those from the pre-shock…

High Energy Astrophysical Phenomena · Physics 2015-06-17 Rajiv Kumar , Indranil Chattopadhyay , Samir Mandal

We consider time-dependent models for rotating accretion flows onto black holes, where a transition takes place from an outer cooling-dominated disc to a radiatively inefficient flow in the inner region. In order to allow for a transition…

Astrophysics · Physics 2009-11-07 J. Gracia , J. Peitz , Ch. Keller , M. Camenzind

It is believed that the spectral state transitions of the outbursts in X-ray binaries (XRBs) are triggered by the rise of the mass accretion rate due to underlying disc instabilities. Recent observations found that characteristics of disc…

High Energy Astrophysical Phenomena · Physics 2025-01-07 Indu K. Dihingia , Yosuke Mizuno , Christian M. Fromm , Ziri Younsi

We consider the behavior of matter in the accretion column that emerges under accretion in binary systems near the surface of a white dwarf. The plasma heated in a standing shock wave near the white dwarf surface efficiently radiates in the…

High Energy Astrophysical Phenomena · Physics 2013-12-18 Andrey Semena , Mikhail Revnivtsev

We calculate the effect of illumination of dwarf nova accretion discs by radiation from a hot, central, white dwarf. We show that only for very hot white dwarfs (Teff ~ 40 000$ K) the inner region of quiescent dwarf nova discs are partially…

Astrophysics · Physics 2009-10-30 J. -M. Hameury , J. -P. Lasota , G. Dubus

Radiation pressure dominated accretion discs may have turbulent velocities that exceed the electron thermal velocities. Bulk Comptonization by the turbulence may therefore dominate over thermal Comptonization in determining the emergent…

High Energy Astrophysical Phenomena · Physics 2018-04-05 Jason Kaufman

The relations among the relative changes of surface density, temperature, disk height and vertical integrated pressure in three kinds of thermally unstable accretion disks were quantitatively investigated by assuming local perturbations.…

Astrophysics · Physics 2009-10-30 Xue-Bing Wu