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Related papers: A generalized solution for advection-dominated acc…

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The standard Advection-Dominated Accretion Flow (ADAF) is studied using a set of self-similar analytical solutions in the spherical coordinates. Our new solutions are useful for studying ADAFs without dealing with the usual mathematical…

High Energy Astrophysical Phenomena · Physics 2015-06-19 Mohsen Shadmehri

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

The thickness of a slim disk is determined by the balance between the radiation force and the vertical component of the gravity of the black hole (BH). It was found that vertical gravity increases with the disk height, and it will decrease…

High Energy Astrophysical Phenomena · Physics 2019-12-04 Junjie Feng , Xinwu Cao , Wei-Min Gu , Ren-Yi Ma

We summarize results from a survey of radiation-dominated black hole accretion flows across a wide range of mass accretion rates, as well as two values of black hole spin and initial magnetic field geometry. These models apply an algorithm…

High Energy Astrophysical Phenomena · Physics 2025-09-16 Lizhong Zhang , James M. Stone , Patrick D. Mullen , Shane W. Davis , Yan-Fei Jiang , Christopher J. White

We propose a model of the accretion flow onto a black hole consisting of the accretion disk with an accreting two-temperature corona. The model is based on assumptions about the radiative and conductive energy exchange between the two…

Astrophysics · Physics 2009-10-31 B. Czerny , A. Rozanska , A. Janiuk , P. T. Zycki

We investigate accretion disc models for the X-ray emission of Seyfert-1 galaxies and the hard state of black-hole X-ray binaries. We concentrate on two hot accretion disc models: advection-dominated accretion flow (ADAF) and recently found…

Astrophysics · Physics 2009-11-10 Feng Yuan , Andrzej A. Zdziarski

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

We examine a new family of global analytic solutions for optically thick accretion disks, which includes the supercritical accretion regime. We found that the ratio of the advection cooling rate, $Q_{\rm adv}$, to the viscous heating rate,…

Astrophysics · Physics 2016-08-30 K. Watarai

Based on a unified description of various accretion flows, we find a long-ignored solution - the effectively optically thin accretion flow, occurring at accretion rates around Eddington value. As a consequence of radiation-pressure…

High Energy Astrophysical Phenomena · Physics 2025-07-01 Mingjun Liu , B. F. Liu , Yilong Wang , Huaqing Cheng , Weimin Yuan

We analyze the broadband photometric light curves of Seyfert 1 galaxies from the Sergeev et al. (2005) sample and find that a) perturbations propagating across the continuum emitting region are a general phenomenon securely detected in most…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Doron Chelouche

The recent {\em Chandra} observation of the radio source at the center of our Galaxy, Sgr A$^*$, puts new constraints on its theoretical models. The spectrum is very soft, and the source is rapidly variable. We consider different models to…

Astrophysics · Physics 2009-11-07 Feng Yuan , Sera Markoff , Heino Falcke

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

To what extent can the one-dimensional slim disk model reproduce the multi-dimensional results of global radiation-hydrodynamic simulations of super-Eddington accretion? With this question in mind, we perform systematic simulation study of…

High Energy Astrophysical Phenomena · Physics 2018-11-07 Takaaki Kitaki , Shin Mineshige , Ken Ohsuga , Tomohisa Kawashima

We construct a numerical model of steady-state, general relativistic (GR) super-Eddington accretion flows in an optically thick, advection-dominated regime, motivated by tidal disruption events wherein super-Eddington accretion assumes a…

High Energy Astrophysical Phenomena · Physics 2023-08-04 T. Mageshwaran , Kimitake Hayasaki

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

It was found that the advection-dominated accretion flow (ADAF)+thin disk model calculations can reproduce the observed spectral energy distributions (SED) of the two low luminosity AGN, provided they are accreting at ~0.01-0.03 Eddington…

Astrophysics · Physics 2009-11-13 Ya-Di Xu , Xinwu Cao

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 that describe advection-dominated accretion flows around black holes. The solutions are obtained by numerically solving a set of coupled ordinary differential equations corresponding to a steady axisymmetric…

Astrophysics · Physics 2009-10-28 Ramesh Narayan , Shoji Kato , Fumio Honma

Photon trapping is believed to be an important mechanism in super-Eddington accretion, which greatly reduces the radiative efficiency as photons are swallowed by the central black hole before they can escape from the accretion flow. This…

High Energy Astrophysical Phenomena · Physics 2023-08-17 Cheng-Liang Jiao

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