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Related papers: Dynamics of Hot Accretion Flow with Thermal Conduc…

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Previous works have clearly shown the existence of winds from black hole hot accretion flow and investigated their detailed properties. In extremely low accretion rate systems, the collisional mean-free path of electrons is large compared…

High Energy Astrophysical Phenomena · Physics 2016-04-20 De-Fu Bu , Mao-Chun Wu , Ye-Fei Yuan

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

We study the accretion flow of a hot gas captured by the black hole gravity in the presence of a thin cold accretion disk. Such geometrical arrangement is expected in Active Galactic Nuclei (AGN) and in galactic X-ray binary systems because…

Astrophysics · Physics 2007-05-23 Sergei Nayakshin

We investigate the dependency of the inflow-wind structure of the hot accretion flow on the kinematic viscosity coefficient. In this regard, we propose a model for the kinematic viscosity coefficient to mimic the behavior of the…

High Energy Astrophysical Phenomena · Physics 2021-09-15 Fatemeh Zahra Zeraatgari , Liquan Mei , Amin Mosallanezhad

Differentially rotating, "advection-dominated" accretion flows are considered in which the heat generated by viscous dissipation is retained in the fluid. The equations of time-dependent quasi-spherical accretion are solved in a simplified…

Astrophysics · Physics 2009-10-31 G. I. Ogilvie

We explore the effects of anisotropic thermal conduction, anisotropic pressure, and magnetic field strength on the hot accretion flows around black holes by solving the axisymmetric, steady-state magnetohydrodynamic equations. The…

High Energy Astrophysical Phenomena · Physics 2022-03-09 Amin Mosallanezhad , Fatemeh Zahra Zeraatgari , Liquan Mei , De-Fu Bu

Since the collisional mean free path of charged particles in hot accretion flows can be significantly larger than the typical length-scale of the accretion flows, the gas pressure is anisotropic to magnetic field lines. For such a large…

High Energy Astrophysical Phenomena · Physics 2021-09-08 S. M. Ghoreyshi , A. R. Khesali

Non-radiating, advection-dominated, accretion flows are convectively unstable. We calculate the two-dimensional (r-theta) structure of such flows assuming that (1) convection transports angular momentum inwards, opposite to normal viscosity…

Astrophysics · Physics 2009-10-31 Eliot Quataert , Andrei Gruzinov

Advection is believed to be the dominant cooling mechanism in optically thin advection-dominated accretion flows (ADAF's). When outflow is considered, however, the first impression is that advection should be of opposite sign in the inflow…

High Energy Astrophysical Phenomena · Physics 2023-01-24 Cheng-Liang Jiao

Two significant progresses have been made in the past years on our understanding of hot accretion flows. One is that only a small fraction of accretion flow available at the outer boundary can finally falls onto the black hole while most of…

High Energy Astrophysical Phenomena · Physics 2015-06-05 Fu-Guo Xie , Feng Yuan

We investigate the dynamics of clumps that coexisted with/in advection-dominated accretion flows by considering thermal conductivity. Thermal conduction can be one of the effective factors in the energy transportation of ADAFs; hence it may…

High Energy Astrophysical Phenomena · Physics 2022-11-09 Hussein Ayad , Maryam Samadi , Shahram Abbassi

We study the thermal structure of the widely adopted two-dimensional advection dominated accretion flow (ADAF) of Narayan & Yi (1995a). The critical radius for a given mass accretion rate, outside of which the optically thin hot solutions…

Astrophysics · Physics 2009-10-31 Myeong-Gu Park , Jeremiah P. Ostriker

The effect of a possible hydrodynamical wind on the nature of hot accretion disk solutions is studied. It is found that the advection dominated branch, in the presence of a wind, maintains the self-similar solution for the disk structure…

Astrophysics · Physics 2009-11-06 Ranjeev Misra , Ronald E. Taam

Observed accretion rates onto the Milky-Way and other local spirals fall short of that required to sustain star formation for cosmological timescales. A potential avenue for this unseen accretion is an inflow in the volume-filling hot phase…

We describe hot, optically-thin solutions for one-temperature accretion disks around black holes. We include cooling by synchrotron, bremsstrahlung, and Comptonization. Our solutions are thermally and viscously stable, with gas temperatures…

Astrophysics · Physics 2016-08-30 A. A. Esin , R. Narayan , E. Ostriker , I. Yi

We consider hot, two-temperature, viscous accretion onto a rotating, unmagnetized neutron star. We assume Coulomb coupling betweenthe protons and electrons, and free-free cooling from the electrons. We show that the accretion flow has an…

Astrophysics · Physics 2009-10-31 Mikhail V. Medvedev , Ramesh Narayan

In a previous paper, we presented the global solution of a new accretion flow model, namely luminous hot accretion flows (LHAFs). In this {\em Letter}, we first show the corresponding thermal equilibrium curve of LHAFs in the mass accretion…

Astrophysics · Physics 2009-11-07 Feng Yuan

Advection-dominated, high-temperature, quasi-spherical accretion flow onto a compact object, recently considered by a number of authors, assume that the dissipation of turbulent energy of the flow heats the ions and that the dissipated…

Astrophysics · Physics 2009-10-30 G. S. Bisnovatyi-Kogan , R. V. E. Lovelace

A self-similar solution for time evolution of quasi-spherical, self-gravitating accretion flows is obtained under the assumption that the generated heat by viscosity is retained in the flow. The solutions are parameterized by the ratio of…

Astrophysics · Physics 2009-11-10 Mohsen Shadmehri

The black hole in our Galactic Center is extremely underluminous for the amount of hot gas available for accretion. Theoretical understanding of this fact rests on a likely but not entirely certain assumption that the electrons in the…

Astrophysics · Physics 2009-11-07 Sergei Nayakshin