Emission-line regions of quasars

Conference · Sun Jan 01 04:00:00 EST 1984 · Ann. N.Y. Acad. Sci.; (United States)

OSTI ID:5887376

Kwan, J

The emission spectra of quasars prominently consist of broad permitted and semiforbidden lines of full width at half-maximum. It has been suggested that the emission lines are produced by photoionization of surrounding gas by the strong central continuum. The power-law UV continuum not only provides a convenient energy source for the line emission, but also creates the wide range of observed high and low ionization species. Theoretical photoionization models have produced the observed line intensities. Two conditions make the photoionization models of the quasar emission-line clouds different from standard nebular calculations: the strong X-ray luminosity of the quasar, and the relatively high density of the quasar emission-line cloud. Among the proposed kinematic models of the broad line gas are the outflow of matter being accelerated by radiation pressure or by a hot wind, as well as ballistic outflow of matter, matter in circular orbits, and matter in parabolic orbits. 41 references.

• Research Organization: Massachusetts Univ., Amherst
• OSTI ID: 5887376
• Report Number(s): CONF-821227-
• Conference Information: Journal Name: Ann. N.Y. Acad. Sci.; (United States) Journal Volume: 422
• Country of Publication: United States
• Language: English

Related Subjects

640103* -- Astrophysics & Cosmology-- Quasi-Stellar
Radio
& X-Ray Sources-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BALMER LINES
COSMIC GASES
COSMIC RADIO SOURCES
ELECTROMAGNETIC RADIATION
EMISSION SPECTRA
ENERGY-LEVEL TRANSITIONS
FLUIDS
FORBIDDEN TRANSITIONS
GALAXY NUCLEI
GASES
IONIZATION
IONIZING RADIATIONS
PHOTOIONIZATION
QUASARS
RADIATIONS
SPECTRA
ULTRAVIOLET RADIATION
X RADIATION