Fitting improved accretion disk models to the multiwavelength continua of quasars and active galactic nuclei

Journal Article · Wed Nov 01 00:00:00 EST 1989 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/167986· OSTI ID:7163960

Sun, Weihsin; Malkan, M A ^[1]

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1. NASA, Goddard Space Flight Center, Greenbelt, MD (USA) California Univ., Los Angeles (USA)

Fits to the ultraviolet-optical-infrared spectra of 60 quasars and active galactic nuclei (AGNs) are investigated, using black hole accretion disk models. The disk is assumed to be geometrically thin and optically thick. The observed spectrum from a black hole accretion disk, rotating (Kerr) or nonrotating (Schwarzschild), is transformed by the geometric inclination effect, Doppler shifts, gravitational redshifts, and gravitational focusing. These effects alter the locally emitted fluxes and produce harder spectra for an observer at higher inclination angles. The relativistic corrections are much more significant in the Kerr geometry since the inner edge of the disk is much closer to the rotating black hole. A simple inverse relation between the inferred black hole mass and the assumed inclination angle was found in the Kerr case, while the inferred accretion rate (solar masses/yr) remains independent of the angle. In the Schwarzschild case, the ratio of the inferred accretion rate to the black hole mass remains roughly constant when the viewing angle changes. In both geometries, low-redshift Seyfert galaxies have relatively low accretion rates, only a few percent of their Eddington luminosities, while the most luminous quasars are accreting near their Eddington limits. 65 refs.

• OSTI ID: 7163960
• Journal Information: Astrophysical Journal; (USA), Vol. 346; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
GALAXY NUCLEI
INFRARED SPECTRA
ULTRAVIOLET SPECTRA
VISIBLE SPECTRA
QUASARS
ACCRETION DISKS
BLACK HOLES
EDDINGTON THEORY
GRAVITATION
MATHEMATICAL MODELS
RED SHIFT
RELATIVITY THEORY
SCHWARZSCHILD METRIC
SEYFERT GALAXIES
SPECTROSCOPY
X-RAY SPECTRA
COSMIC RADIO SOURCES
FIELD THEORIES
GALAXIES
GENERAL RELATIVITY THEORY
METRICS
SPECTRA
640102* - Astrophysics & Cosmology- Stars & Quasi-Stellar
Radio & X-Ray Sources
640105 - Astrophysics & Cosmology- Galaxies