The asymmetric, broad hydrogen emission lines of Seyfert 1 galaxies

Abstract

view Abstract Citations (64) References (4) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The asymmetric, broad hydrogen emission lines of Seyfert 1 galaxies. Capriotti, E. ; Foltz, C. ; Byard, P. Abstract Hfl emission-line profiles are calculated for various choices of parameters pertaining to a schematic Seyfert 1 galaxy model. The basic model consists of a spherical system of discrete clouds which is expanding with a velocity of between 1 0 and 1 0 km 1 A point source of ionizing radiation is assumed to be situated at the center of the expanding system. Each cloud is assumed to be spherical in shape and to be ionized only on the thin surface region which is exposed directly to the central source of ionizing radiation. A continuous opacity source such as dust is assumed to be present in the neutral part of each cloud so that, to an observer located outside the expanding system, approaching clouds would appear fainter than receding clouds. This would cause the blueward half of the resulting H line profile to be suppressed relative to the redward half. However, shadowing of receding clouds by approaching clouds would have the opposite effect. For the usually quoted value of the covering factor of roughly 10%, the former effect is much greater than the latter. A broad, asymmetric line is produced in this manner. The composite spectra produced by combining the broad, asymmetric components of Hfl for the schematic model described here with arbitrarily chosen intensities for the narrow component (AA/A 10- ) of Hfl and [0111] A4959 and A5007 have the general features of spectra observed for many Seyfert 1 galaxies and quasars. Subject heading: galaxies: Seyfert Publication: The Astrophysical Journal Pub Date: June 1979 DOI: 10.1086/157126 Bibcode: 1979ApJ...230..681C Keywords: Galactic Radiation; H Beta Line; Line Shape; Seyfert Galaxies; Spectral Line Width; Astronomical Models; Emission Spectra; Photoionization; Quasars; Astrophysics; Emission Lines:Seyfert Galaxies; H Beta:Seyfert Galaxies; Seyfert Galaxies:Models full text sources ADS | data products NED (3)