The Bowen Fluorescence Mechanism in Planetary Nebulae and Seyfert Galaxy Nuclei

Abstract

The efficiency of the Bowen fluorescence mechanism in models of planetary nebulae and Seyfert galaxy nuclei has been calculated by solving the equation of transfer for He II Ly -o( and the Bowen lines using the Feautrier method. The calculated efficiencies, which do not show significant differences between planetary nebulae and Seyfert galaxies, range from about 40% to 50% for realistic models. These values are somewhat higher than recent empirical determinations of Bowen conversion in planetary nebulae. Certain discrepancies between theoretical and observed line ratios are noted, however, which make the comparison with observation ambiguous. The efficiencies are shown to be rather insensitive to changes in various parameters. It is also noted that observations do not necessarily show that the Bowen lines are systematically weaker in Seyfert galaxy nuclei than in planetary nebulae.