Near-ultraviolet spectroscopy of Seyfert nuclei - Reddening and Bowen fluorescence

Abstract

view Abstract Citations (23) References (35) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Near-Ultraviolet Spectroscopy of Seyfert Nuclei: Reddening and Bowen Fluorescence Malkan, Matthew A. Abstract Spectra with high signal-to-noise ratios extending down to the atmospheric ultraviolet cut-off have been obtained for 11 Seyfert nuclei with narrow emission lines. In all objects the He II lines at 3204 A and 4686 A were measured simultaneously. Their ratio gives an estimate of reddening accurate to 0.14 mag in E(B-V). The redshifts of nine of the Seyfert galaxies are sufficient to allow detection of the O III 3133 line A, produced by Bowen fluorescence of He II Ly-alpha photons. The inferred efficiency of the Bowen mechanism ranges from 15 to 50 percent. The lower values, which are considerably less than the efficiencies found in planetary nebulae, are observed in Seyfert 2 nuclei with systematically weaker emission lines from high-excitation, high-density gas. In contrast, the Seyfert 1 and high-excitation Seyfert 2 nuclei have more 'normal' Bowen efficiencies. Several possible explanations are considered. Publication: The Astrophysical Journal Pub Date: November 1986 DOI: 10.1086/164718 Bibcode: 1986ApJ...310..679M Keywords: Astronomical Spectroscopy; Fluorescence; Galactic Nuclei; Interstellar Extinction; Seyfert Galaxies; Ultraviolet Astronomy; Emission Spectra; Near Ultraviolet Radiation; Oxygen Spectra; Astrophysics; GALAXIES: NUCLEI; GALAXIES: SEYFERT; RADIATION MECHANISMS full text sources ADS | data products SIMBAD (11) NED (11)