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Session 98 - AGN-Absorption/Emission.
Display session, Thursday, January 16
One of the defining features of active galactic nuclei (AGN) is the presence of broad emission lines in their optical and ultraviolet spectra. The line wings extend to velocities \ge 10^4 km s^-1, suggesting that the lines form in gas very close to the central black hole that powers the AGN. We have proposed that the line emission takes place in a line-driven wind emerging from the accretion disk that feeds the black hole. Here we present photoionization models of the wind/disk. Besides providing us with line ratios, the models allow us to calculate line profiles, and the radii at which various lines emit. The anisotropic optical depths in the wind ensure that the line profiles are single peaked, in spite of the fact that the emitting gas orbits the black hole on essentially circular orbits. We compare the results to observations of high luminosity quasars.
Program listing for Thursday