New results on quasars emission-line redshift differences

New optical spectra of radio and optically selected quasars covering a wide range in luminosity have revealed several effects associated with the redshift differences between their strong emission lines. The range of the difference between the Mg II 2800 and C IV 1549 lines exceeds 4000 km/s in a sample of high-luminosity, optically selected objects, which is significantly larger than previously detected values of this difference (600 km/s). The results obtained are found to be consistent with the model of Kallman and Krolik (1986) in which the opacity source responsible for the redshift differences is electron scattering and the nature of the implied radial motion is infall. The results also suggest a stratified ionization structure of the quasar broad-line region, consistent with the results for the broad-line regions of centain Seyfert galaxies based on emission-line variability. 21 refs