منابع مشابه
Time-dependent quasi-spherical accretion
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 one-dimensional model that neglects the latitudinal dependence of the flow. A self-similar solution is presented that has finite size, mass, angular momentum...
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Results are presented from a time–dependent, numerical investigation of spherical accretion onto black holes, within the framework of relativistic radiation hydrodynamics. We have studied the stability of self–consistent, stationary solutions of black hole accretion with respect to thermal and radiative perturbations and also the non– linear evolution of unstable, high temperature models, heate...
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We study a phenomenological model for the continuum emission of Seyfert galaxies. In this quasi-spherical accretion scenario, the central X-ray source is constituted by a hot spherical plasma region surrounded by spherically distributed cold dense clouds. The cold material is radiatively coupled with the hot thermal plasma. Assuming energy balance, we compute the hard X-ray spectral slope Γ and...
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We compare different examples of spherical accretion onto a gravitating mass. Limiting cases include the accretion of a collisionally dominated fluid and the accretion of collisionless particles. We derive expressions for the accretion rate and density profile for semi-collisional accretion which bridges the gap between these limiting cases. Particle crossing of the Hill sphere during the forma...
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Stationary spherical accretion onto black holes is certainly a well–known and extensively studied topic (for a comprehensive review see Nobili, Turolla and Zampieri , Zampieri, Miller and Turolla ). Up to now all time–dependent investigations of spherical accretion have been concerned either with the analysis of the stability of isothermal , isentropic 4 and optically thick 6 flows or with the ...
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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 1999
ISSN: 0035-8711,1365-2966
DOI: 10.1046/j.1365-8711.1999.02637.x