Thick accretion disks around black holes and the UV/soft X-ray excess in quasars

Journal Article · Fri Apr 01 00:00:00 EST 1988 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/166175· OSTI ID:7222681

Madau, P

The dependence on viewing angle of the observed disk spectrum of geometrically and optically thick accretion disks around supermassive black holes in quasars is investigated. A model of radiation-supported thick disks is analyzed, and the emitted spectrum is computed as a function of the inclination angle. The radiation field along the rotation axis is greatly enhanced by the multiple scattering of photons off the walls of the inner, very hot and luminous, funnel-shaped region. It is found that the funnel dominates the emission from tori which are viewed more pole-on, i.e., at small viewing angles from the symmetry axis of the torus. This gives rise to a UV/soft X-ray thermal component. Tori viewed nearly edge-on, i.e., at large viewing angles from the symmetry axis, appear less luminous and cooler, possibly accounting for the optical/UV bump. 54 references.

• Research Organization: Scuola Internazionale Superiore di Studi Avanzati, Trieste (Italy)
• OSTI ID: 7222681
• Journal Information: Astrophys. J.; (United States), Vol. 327
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BLACK HOLES
ACCRETION DISKS
QUASARS
SOFT X RADIATION
ULTRAVIOLET RADIATION
ANGULAR MOMENTUM
SEYFERT GALAXIES
SUPERMASSIVE STARS
COSMIC RADIO SOURCES
ELECTROMAGNETIC RADIATION
GALAXIES
IONIZING RADIATIONS
RADIATIONS
STARS
X RADIATION
640102* - Astrophysics & Cosmology- Stars & Quasi-Stellar
Radio & X-Ray Sources