Far-ultraviolet and optical spectrophotometry of X-ray selected Seyfert galaxies

Journal Article · Sun Jun 01 04:00:00 EDT 1986 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/164237· OSTI ID:5199696

Clarke, J T; Bowyer, S; Grewing, M

Five X-ray selected Seyfert galaxies were examined via near-simultaneous far-ultraviolet and optical spectrophotometry in an effort to test models for excitation of emission lines by X-ray and ultraviolet continuum photoionization. The observed Ly-alpha/H-beta ratio in the present sample averages 22, with an increase found toward the high-velocity wings of the H lines in the spectrum of at least one of the Seyfert I nuclei. It is suggested that Seyfert galaxies with the most high-velocity gas exhibit the highest Ly-alpha/H-beta ratios at all velocities in the line profiles, and that sometimes this ratio may be highest for the highest velocity material in the broad-line clouds. Since broad-lined objects are least affected by Ly-alpha trapping effects, they have Ly-alpha/H-beta ratios much closer to those predicted by early photoionization calculations. 21 references.

• Research Organization: NASA, Marshall Space Flight Center, Huntsville, AL; California Univ., Berkeley; Tuebingen Universitaet, West Germany
• OSTI ID: 5199696
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 305; ISSN ASJOA
• 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
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
ELECTROMAGNETIC RADIATION
EMISSION SPECTRA
FAR ULTRAVIOLET RADIATION
GALAXIES
GALAXY NUCLEI
LINE WIDTHS
LYMAN LINES
RADIATIONS
SEYFERT GALAXIES
SPECTRA
SPECTROPHOTOMETRY
ULTRAVIOLET RADIATION
ULTRAVIOLET SPECTRA
VISIBLE SPECTRA