Quasars are a frustratingly unsolved problem in astrophysics. For almost 40 years quasars and AGN have presented an ever proliferating list of diverse and confusing phenomenology from optical to X-ray wavelengths: Broad emission lines, narrow absorption lines, broad absorption lines, `warm' soft X-ray absorbers, fluorescent X-ray Fe-K emission, and Compton scattering 'humps'. Progress has been slow, with each of these phenomena treated more or less in isolation. The result has been that quasars have been increasingly sidelined in astrophysics despite their prominence in the sky. The problem, I believe, is not that we do not know enough physics, but rather that we do not have the right geometry. I have proposed a simple geometric and kinematic model that allows all of these diverse phenomena to be understood as part of a single structure. Once in place, this structure suggests a natural physical interpretation, and constrains models. With minor extensions the model also suggests explanations for the Baldwin effect (and its relatives), the "ionization" cones in AGN, and the lack of high luminosity obscured AGN. The need for a "molecular torus" in AGN is also much weaker - if this model is correct. The model can be easily tested and has passed several initial tests since publication, but many important consequences remain to be investigated.
Friday, 06 Sep 2002
11:00am
Array Operations Center Auditorium
Local Host: Jim Ulvestad