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Session 25 - Seyfert Galaxies.
Oral session, Wednesday, January 07
I will present synthetic spectra and response functions of the red giant stellar line emission model of active galactic nuclei (e.g., Kazanas 1989). Our results agree with the fundamental line emission characteristics of AGNs within the model uncertainties provided the following new 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). In addition, I will also discuss several interesting features of stellar wind models. For instance, provided the density of the intercloud (interstellar) medium is high enough, the stellar winds are comet-shaped, with the shock fronts having higher densities than the tails. As a result, the densities in the inverse Stromgren regions of the outbound clouds are lower than those of the inbound clouds. For models in which an accretion disk occults the BLR, this results in line emission and absorption (BAL) shifts even though the cloud phase space distribution function is independent of the velocity vector direction. More specifically, for our models (in which the mean ionization parameter falls with distance from the black hole), the broadest line emission/absorption is red-shifted and the narrowest emission and absorption is blue-shifted for lines similar to C IV, N V, and O VI. On the other hand, Lya has a weaker dependence upon the ionization parameter. Therefore, it has smaller shifts, as is observed. These results are fully consistent with the observation that the C IV red wing responds faster than the blue wing in NGC 5548 (e.g., Done Krolik 1996).
Program listing for Wednesday