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Related papers: Analytical solution for the structure of ADAFs

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We implement a new semi-analytical approach to investigate radially self-similar solutions for the steady-state advection-dominated accretion flows (ADAFs). We employ the usual $\alpha$-prescription for the viscosity and all the components…

High Energy Astrophysical Phenomena · Physics 2018-08-08 Asiyeh Habibi , Shahram Abbassi , Mohsen Shadmehri

A model for advection-dominated accretion flows (ADAFs) in a global magnetic field is proposed. In contrast to the well known ADAF models in which the viscosity of a fluid determines both angular momentum transfer and energy dissipation in…

Astrophysics · Physics 2009-10-31 Osamu Kaburaki

We solve the set of hydrodynamic (HD) equations for optically thin Advection Dominated Accretion Flows (ADAFs) by assuming radially self-similar in spherical coordinate system $ (r, \theta, \phi) $. The disk is considered to be steady state…

High Energy Astrophysical Phenomena · Physics 2015-11-12 Fateme Zahra Zeraatgari , Shahram Abbassi

In a previous paper, we described new analytic formulae for optically-thick supercritical accretion flows (Watarai 2006, hereafter paper 1). Here we present analytic formulae for optically-thin one-temperature accretion flows including the…

Astrophysics · Physics 2015-06-24 Ken-ya Watarai

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

We review some of the properties of Advection-Dominated Accretion Flow (ADAF) models and show that they successfully describe many astrophysical systems. Despite these successful applications some fundamental problems still remain to be…

Astrophysics · Physics 2009-10-30 Jean-Pierre Lasota

In this paper, the self-similar solution of resistive advection dominated accretion flows (ADAF) in the presence of a pure azimuthal magnetic field is investigated. The mechanism of energy dissipation is assumed to be the viscosity and the…

High Energy Astrophysical Phenomena · Physics 2015-06-03 Kazem Faghei

We investigated effects on flow variables of transonic advection-dominated accretion flows (ADAFs) for different outer boundary locations (BLs) with a changing energy constant ($E$) of the flow. We used the ADAF solutions and investigated a…

High Energy Astrophysical Phenomena · Physics 2019-05-15 Rajiv Kumar , Wei-Min Gu

Observations and numerical magnetohydrodynamic (MHD) simulations indicate the existence of outflows and ordered large-scale magnetic fields in the inner region of hot accretion flows. In this paper we present the self-similar solutions for…

Astrophysics · Physics 2009-11-13 De-Fu Bu , Feng Yuan , Fu-Guo Xie

When we model black hole accretion sources such as active galactic nuclei and black hole X-ray binaries as advection-dominated accretion flows (ADAFs), it is neccesary to use the global solution to the equations rather than the simpler…

Astrophysics · Physics 2009-11-13 Feng Yuan , Renyi Ma , 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 solved analytically viscous two-dimensional (2D) fluid equations for accretion and outflows in spherical polar coordinates ($r, \theta, \phi$) and obtained explicitly flow variables in $r-$ and $\theta -$directions around black holes…

High Energy Astrophysical Phenomena · Physics 2018-07-04 Rajiv Kumar , Wei-Min Gu

We consider height-integrated equations of an advection-dominated accretion flow (ADAF), assuming that there is no mass outflow. We include convection through a mixing length formalism. We seek self-similar solutions in which the rotational…

Astrophysics · Physics 2009-10-31 Ramesh Narayan , Igor V. Igumenshchev , Marek A. Abramowicz

The present study examines self-similarity evolution of advection dominated accretion flow (ADAF) in the presence of a toroidal magnetic field. In this research, it was assumed that the angular momentum transport is due to viscous…

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

Recent work on advection-dominated accretion flows (ADAFs) is reviewed. The article concentrates on an optically thin branch of ADAFs which is present at mass accretion rates below a critical value $\sim(10^{-2}-10^{-1})$ the Eddington…

Astrophysics · Physics 2007-05-23 Ramesh Narayan

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

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

Advection-dominated accretion flows (ADAFs) are known to be convectively unstable for low values of the viscosity parameter alpha. Two-dimensional axisymmetric hydrodynamic simulations of such flows reveal a radial density profile which is…

Astrophysics · Physics 2009-10-31 Igor V. Igumenshchev , Marek A. Abramowicz , Ramesh Narayan

A model for axisymmetric magnetized accretion flow is proposed. The dominant mechanism of energy dissipation is assumed to be the magnetic diffusivity due to turbulence in the accretion flow. In analogy to the advection-dominated accretion…

Astrophysics · Physics 2009-11-07 Mohsen Shadmehri

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
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