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Related papers: Preheated Advection Dominated Accretion Flow

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We present self-similar solutions for advection -dominated accretion flows with thermal conduction in the presence of outflows. Possible effects of outflows on the accretion flow are parametrized and a saturated form of thermal conduction,…

Astrophysics · Physics 2009-11-13 Mohsen Shadmehri

We examine the effects of a hydrodynamical wind on advection dominated accretion flows with thermal conduction in the presence of a toroidal magnetic field under a self-similar treatment. The disk gas is assumed to be isothermal. For a…

Astrophysics of Galaxies · Physics 2010-12-16 S. Abbassi , J. Ghanbari , M. Ghasemnezhad

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

Astrophysics · Physics 2011-08-31 S. Abbassi , J. Ghanbari , S. Najjar

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

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

Observations of X-ray luminous elliptical galaxies suggest that the accretion rate onto the central supermassive black hole can reach a substantial fraction of the Bondi rate. However, classical accretion theory applicable to such hot…

High Energy Astrophysical Phenomena · Physics 2026-02-02 Cheng-Liang Jiao , Liying Zhu , Er-gang Zhao , Xiang-dong Shi

We find a new two-temperature hot branch of equilibrium solutions for stationary accretion disks around black holes. In units of Eddington accretion rate defined as $10L_{\rm Edd}/c^2$, the accretion rates to which these solutions…

Astrophysics · Physics 2015-06-24 Feng Yuan

The hot accretion flow is usually optically thin in the radial direction, therefore the photons produced at one radius can travel for a long distance without being absorbed. These photons thus can heat or cool electrons at other radii via…

Astrophysics · Physics 2009-06-23 Feng Yuan , Fuguo Xie , Jeremiah P. Ostriker

We perform as the first time hydrodynamic simulations to study the properties of hot accretion flow (HAF) around a neutron star (NS). The energy carried by the HAF will eventually be radiated out at the surface of the NS. The emitted…

High Energy Astrophysical Phenomena · Physics 2019-05-01 De-Fu Bu , Er-Lin Qiao , Xiao-Hong Yang

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

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

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

In this Letter we investigate the properties of advection-dominated accretion flows (ADAFs) fed by the evaporation of a Shakura-Sunyaev accretion disk (SSD). In our picture the ADAF fills the central cavity evacuated by the SSD and extends…

Astrophysics · Physics 2009-10-31 R. Turolla , C. P. Dullemond

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

We report here on a calculation of thermalization time-scale of the two temperature advection dominated accretion flow (ADAF) model. It is established that time required to equalize the electron and ion temperatures via electron-ion…

Astrophysics · Physics 2009-10-31 David Tsiklauri

Observations and numerical simulations have shown that outflows generally exist in the accretion process. We revisit the thermal equilibrium solutions of black hole accretion flows by including the role of outflows. Our study focuses on the…

High Energy Astrophysical Phenomena · Physics 2022-05-18 Wen-Biao Wu , Wei-Min Gu , Mouyuan Sun

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

Two-temperature advection dominated accretion flow (ADAF) or hot ion tori (HIT) models help explain low luminosity stellar and galactic accreting sources and may complement observational support for black holes in nature. But low radiative…

Astrophysics · Physics 2007-05-23 Eric G. Blackman

A summary is given of the high-lights during the Reykjavik Midsummer Symposium on Non-Linear Phenomena in Accretion Discs around Black Holes. Such high-lights include the recent advances on understanding: 1) the accretion disc solution…

Astrophysics · Physics 2007-05-23 Roland Svensson

We present global solutions of optically thin, two-temperature black hole accretion disks incorporating magnetic fields. We assume that the {\pi}{\phi}-component of the Maxwell stress is proportional to the total pressure, and prescribe the…

High Energy Astrophysical Phenomena · Physics 2015-05-30 Hiroshi Oda , Mami Machida , Kenji E. Nakamura , Ryoji Matsumoto , Ramesh Narayan