Physical properties of thick supercritical accretion disks

Journal Article · Sat May 15 04:00:00 EDT 1982 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/159941· OSTI ID:5100647

Wiita, P J

Recent models of thick, super-Eddington accretion disks around black holes that were devised by Paczynski and Wiita are analyzed and expanded upon. The shape and ratio of disk luminosity to Eddington luminosity essentially depend upon the inner radius of the disk and the form of the (non-Keplerian) angular momentum distribution, while the size and actual luminosity grow linearly with the mass of the black hole. Two approaches are used to estimate the central temperatures and densities of such disks for different polytropic indices. In one, the surface temperature and density are found first with the help of a parameter describing the ratio of radiation pressure to gas pressure in the atmosphere of the disk. Then the interior parameters, including average values for the viscosity, can be found. The alternative approach fixes the form of the viscosity via a modification of the ''..cap alpha..-disk'' relations, and then proceeds to yield values of central and surface variables. Using either method, physical constraints involving mechanical equilibrium, the total mass of the disk, or the onset of nuclear fusion are found to stringently limit self-consistent models. In particular, it is difficult to build thick disks that are less massive than a nonrotating central black hole if its mass is greater than about 10/sup 7/ M/sub sun/. However, somewhat more general models for the disk structure along with consideration of rotating black holes can probably provide enough luminosity to power the most active galactic nuclei.

• Research Organization: Department of Astronomy and Astrophysics, University of Pennsylvania; and Theoretical Astrophysics Group, Tata Institute of Fundamental Research
• OSTI ID: 5100647
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 256:2; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATMOSPHERES
BLACK HOLES
GALAXY NUCLEI
MATHEMATICAL MODELS
MATHEMATICS
NUMERICAL ANALYSIS
PHYSICAL PROPERTIES
RADIATION PRESSURE
STAR ACCRETION
STAR EVOLUTION
STAR MODELS
STELLAR ATMOSPHERES
VISCOSITY