Line Emission from Stellar Winds in Active Galactic Nuclei

Abstract

This dissertation presents synthetic spectra and response functions of the red giant stellar line emission model of active galactic nuclei. Our results agree with the fundamental line emission characteristics of active galactic nuclei within the model uncertainties if the following additional assumptions are made: 1) the mean stellar mass loss rates decrease with distance from the black hole, and 2) the mean ionization parameters are lower than those postulated in Kazanas (1989). For models with enhanced mass loss, the zero-intensity-full-widths of the line profiles are proportional to the black hole mass to the power of 1/3. This scaling relation suggests that the black hole masses of NLS1s (narrow-line Seyfert 1s) are relatively low. Models with enhanced mass loss also predict minimum line/continuum delays that are proportional to the zero-intensity-full-widths of the profiles. Because of their high column densities, these models yield triangle-shaped response functions, which are not generally observed. On the other hand, models without enhanced mass loss yield line-continuum delays that are proportional to the square root of the continuum luminosity, which is constant with empirical results. Models with high enough intercloud (interstellar) medium densities and a BLR-occulting accretion disk have line shifts. The broadest line emission and absorption profile components of lines similar to C IV, N V, and O VI are redshifted. Conversely, the narrowest emission and absorption profile components are blueshifted in such models. These results appear to agree with observations (e.g., Done & Krolik 1996).