X-ray spectra of PG quasars. II - the X-ray-ultraviolet excess of PG 1211 + 143

Journal Article · Sun Mar 01 04:00:00 EST 1987 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/165098· OSTI ID:6320126

Bechtold, J; Czerny, B; Elvis, M; Fabbiano, G; Green, R F

Observations of the quasar PG 1211 + 143 are presented and its continuum is modelled in terms of an accretion disk and an underlying power law. The X-ray spectrum in the Einstein imaging proportional counter band is well described by a power law with the very steep spectral index 2.2 + or - 0.4. The overall continuum spectral energy distribution can be described as a power law with alpha roughly 1.2 from the infrared to about 1 keV, with the optical, ultraviolet, and soft X-rays forming a large excess above this power law. If the soft X-ray excess is attributed to emission from a physically thin, optically thick accretion disk, then the implied accretion rate is super-Eddington, from which it is concluded that the application of this simple model is not valid. The observed broad-line ratios in PG 1211 + 143 imply broad-line cloud densities that are somewhat higher than those usually derived for quasars. 82 references.

• Research Organization: Steward Observatory, Tucson, AC; Harvard-Smithsonian Center for Astrophysics, Cambridge, MA; Kitt Peak National Observatory, Tucson, AZ
• OSTI ID: 6320126
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 314; 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
ACCRETION DISKS
COSMIC RADIO SOURCES
ELECTROMAGNETIC RADIATION
ENERGY SPECTRA
IONIZING RADIATIONS
MATHEMATICAL MODELS
QUASARS
RADIATIONS
SOFT X RADIATION
SPECTRA
SPECTROSCOPY
X RADIATION
X-RAY SPECTRA