John Everett (CITA)
Observers are increasingly finding absorption-line features with wide ranges in velocity and ionization, and are constraining the columns, metallicities, and even acceleration of absorption systems in AGNs. I present wind models that use these observations to help constrain acceleration mechanisms for accretion-disk winds. Using observations of X-ray absorption systems, I present results for high-velocity, highly-ionized winds launched close to the central black hole, showing that pure continuum driving for such high velocity flows does not produce the observed line features. I also present semi-analytical models tying together continuum-driving, non-Sobolev line-driving, and magneto-centrifugal driving in AGN winds launched farther out from the central black hole. I'll specifically address whether MHD winds can act as "shields" to increase the efficiency of radiative acceleration, and how MHD winds are modified by radiative acceleration.