Astronomy and Astrophysics – Astrophysics
Scientific paper
May 1990
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1990apj...354..446w&link_type=abstract
Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 354, May 10, 1990, p. 446-467.
Astronomy and Astrophysics
Astrophysics
82
Active Galactic Nuclei, Emission Spectra, Line Spectra, Seyfert Galaxies, Ultraviolet Spectra, Visible Spectrum, Astronomical Photometry, Balmer Series, Doppler Effect, Hydrogen, Lyman Alpha Radiation
Scientific paper
The results of an extensive coordinated UV and optical spectroscopic study of the Seyfert 1 galaxy NGC 5548 are presented. The very broad component has a blueshift of 2000 km/s, possibly indicating obscuration in the innermost parts of an accretion disk. Unlike Ly-alpha, the very broad C IV 1549 A does not continue to increase with the UV continuum at large flux levels. For the broad component, the ratio semiforbidden C III 1909 A/C IV 1549 A is independent of the continuum luminosity, suggesting a large ionization parameter. The Balmer decrement in the broad component is smaller when the continuum is brighter. Ly-alpha and H-gamma increase more than H-alpha and H-beta with increasing UV flux. The He II lines are very broad and change by a factor of up to four. They seem to react quickly to UV continuum changes, and there is no need to invoke accretion events to explain their variability.
Barr Paul
Barylak Michael
Gilmozzi Robert
Heck Andre
Maoz Dan
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