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Session 25 - Seyfert Galaxies.
Oral session, Wednesday, January 07
Georgetown,
Bulk radial motion of BLR gas can be detected by the response of line profiles to changes in the photo-ionizing continuum. Cross-correlation of time series of observations of the red and blue wings of emission lines is the most powerful way of determining the direction of motion (Gaskell, 1988, ApJ, 325, 114). Suitable series of observations are now available for many AGNs. The red-wing/ blue-wing variability of all objects rules out pure inflow and pure outflow. Detailed study of the C IV profile of NGC 5548, the AGN with the best data available, shows evidence for some net radial inflow (Korista et al. 1995, ApJS, 97, 285; Done amp; Krolik 1996, ApJ, 463, 144). We consider essentially all AGNs with suitable data and show that, after appropriate allowance for the errors in the cross-correlation method, profile variations of the C IV line are consistent with a slight, but significant net inflow in all cases. We discuss the effect of possible He II contamination of the red wing of C IV.
