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We present an analytic solution for accretion of a gaseous medium with adiabatic equation of state onto a charged dilaton black hole which moves at a constant velocity. We determine the four-velocity of accreted flow and find that it…

General Relativity and Quantum Cosmology · Physics 2022-06-07 Rong-Jia Yang , Yinan Jia , Lei Jiao

By taking into account photon absorption, we investigate the vertical structure of accretion flows with comparable radiation and gas pressures. We consider two separate energy equations for matter and radiation in the diffusion limit. In…

High Energy Astrophysical Phenomena · Physics 2019-08-10 Maryam Samadi , Shahram Abbassi , Wei-Min Gu

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

Global solutions of optically thick advective accretion disks around black holes are constructed. The solutions are obtained by solving numerically a set of ordinary differential equations corresponding to a steady axisymmetric…

Context: Accretion onto galactic and supermassive black holes occurs in different modes, which are documented in hard and soft spectral states, commonly attributed to an advection-dominated flow (ADAF) inside a truncated disk and standard…

Astrophysics · Physics 2009-11-11 F. Meyer , B. F. Liu , E. Meyer-Hofmeister

In our recent paper, we have obtained a model solution to the problem of radiation-inefficient accretion flows (RIAFs) in a global magnetic field (so called, resistive RIAF model), which is asymptotically exact in outer regions of such…

High Energy Astrophysical Phenomena · Physics 2015-06-11 Osamu Kaburaki

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

A supermassive black hole in the nucleus of an elliptical galaxy at the centre of a cool-core group or cluster of galaxies is immersed in hot gas. Bondi accretion should occur at a rate determined by the properties of the gas at the Bondi…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Ramesh Narayan , Andrew C. Fabian

We investigate the global structure of the advection dominated accretion flow around a Schwarzschild black hole where the accretion disc is threaded by toroidal magnetic fields. We consider synchrotron radiative process as an effective…

High Energy Astrophysical Phenomena · Physics 2017-11-29 Biplob Sarkar , Santabrata Das , Samir Mandal

Observations of the hot gas, which is surrounding Sgr A* and a few other nearby galactic nuclei, imply that mean free paths of electron and proton are comparable to gas capture radius. So, hot accretion flows likely proceed under week…

High Energy Astrophysical Phenomena · Physics 2015-05-13 J. Ghanbari , S. Abbassi , M. Ghasemnezhad

Outflows and convective motions in accretion flows have been intensively discussed recently in the context of advection-dominated accretion flow (ADAF) based on two-dimensional (2D) and three-dimensional (3D) hydrodynamical simulations. We,…

Astrophysics · Physics 2007-05-23 Mami Machida , Ryoji Matsumoto , and Shin Mineshige

The global structure of optically thin hot accretion disks with radial advection included has been investigated. We solve the full energy conservation equation explicitly and construct the radial structure of the disk. It is found that…

Astrophysics · Physics 2016-08-30 Xingming Chen

Using mean field MHD, we discuss the energetics of optically thin, two temperature, advection-dominated accretion flows (ADAFs). If the magnetic field is tangled and roughly isotropic, flux freezing is insufficient to maintain the field in…

Astrophysics · Physics 2009-10-31 Eliot Quataert , Ramesh Narayan

We present self-similar solutions for advection-dominated accretion flows with radial viscous force in the presence of outflows from the accretion flow or infall. The axisymmetric flow is treated in variables integrated over polar sections…

Astrophysics · Physics 2009-10-31 Thomas Beckert

We show that, unlike the results presented previously in the literature, the transition from an outer Shakura-Sunyaev disk (SSD) to an advection-dominated accretion flow (ADAF) is possible for large values of the viscosity parameter $\alpha…

Astrophysics · Physics 2007-05-23 Wei-Min Gu , Ju-Fu Lu

Astronomers have discovered many potential black holes in X-ray binaries and galactic nuclei. These black holes are usually identified by the fact that they are too massive to be neutron stars. Until recently, however, there was no…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Kristen Menou , Eliot Quataert , Ramesh Narayan

Astronomers have discovered many potential black holes in X-ray binaries and galactic nuclei. These black holes are usually identified by the fact that they are too massive to be neutron stars. Until recently, however, there was no…

Astrophysics · Physics 2007-05-23 K. Menou , E. Quataert , R. Narayan

Viscous rotating accretion flows around black holes become advection-dominated when the accretion rate $\dot M$ is sufficiently low. Most of the accretion energy in such flows is stored within the gas and advected radially inward. The…

Astrophysics · Physics 2011-05-23 Ramesh Narayan , Insu Yi , Rohan Mahadevan

We investigate the relativistic, viscous, advective, neutrino-dominated accretion flows (NDAFs) around rotating stellar mass black holes, incorporating neutrino cooling. By adopting an effective potential to describe the spacetime geometry…

High Energy Astrophysical Phenomena · Physics 2025-01-14 Amit Kumar , Sayan Chakrabarti , Santabrata Das

Using two-dimensional simulations of non-radiative viscous rotating black hole accretion flows, we show that the flows with alpha~0.1-0.3 self-organize to form stationary unipolar or bipolar outflows accompanied by global meridional…

Astrophysics · Physics 2009-10-31 Igor V. Igumenshchev
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