Semianalytic Models of Two-Phase Disk Winds in Active Galactic Nuclei with Combined Hydromagnetic and Radiative Driving

Abstract

(abridged) We present a semianalytic model of steady-state magnetically and radiatively driven disk outflows in Active Galactic Nuclei (AGNs) consisting of a continuous wind with embedded clouds. The continuous outflow is launched from the disk surface as a centrifugally driven wind, whereas the clouds are uplifted from the disk by the ram pressure of the continuous outflow. In addition, the continuous wind and clouds are subject to both line and continuum radiative acceleration. We describe this model in detail, outline the tests used to verify its accuracy, and compare it to other outflow models, showing possible difficulties with some past line-driven models. We then perform a comprehensive parameter study to explore the dependence of the continuous wind on the relevant physical parameters. We find that clouds have a significant impact on the geometry, density, and velocity in the continuous wind, changing the terminal velocity by up to 50%. Furthermore, line driving is the dominant acceleration mechanism for clouds; continuum driving can also become important for dusty clouds. We find that radiative acceleration can have a significant impact on the velocities in the continuous wind and note that the radiative acceleration comes largely from continuum opacities, not from line driving as in some previous models. When the continuous winds are dusty, their terminal velocities change by approximately 20% to 30% (depending on the type of dust).