Numerical Simulations of OUtflows in Quasars: The Microphysics of BAL Winds

This work builds upon a project now supported by NASA ATP (NAG5-12020, Tlu?Hydrodynamics of Photoionized Flows: probing conditions in starbllrst galaxies and star-forming regions). We (Will Henney, Jane Arthur, and Robin Williams) are extending Cloudy to do MHD with time dependent ionization and advective effects. The emphasis is on the low-velocity flows (1)< 100 km/s) near an irradiated molecular cloud for application to the starburst phenomenon. A first account of this work is published in Ferland et a!. (2002). The aspects of the current problem dealing with MHD motions and their effects on the ionization and thermal structure are supported by this award. The flows that are the focus of the starburst project are usually somewhat close to D-critical, or at about the speed of sound (~10 kml s). Those simulations have never encountered flow velocities :;>102kml s. Radiative transfer also is relatively unimportant - the regions are dusty so lines don't migrate far from their origin, and the velocities are so small that continuum overlap is not an issue. The BAL outflows present a nearly unique problem - only supernovae display similar velocities. The support requested here will go entirely into the development of the multi-grid approach to dealing with overlap and the large outflow velocities. The amount of code development that is needed can be performed by a knowledgeable worker in 6 - 9 months. This will leave sufficient time to apply our methods to the BAL problem itself.