Modeling the Spectral Signatures of Accretion Disk Winds: A New Monte Carlo Approach

Bipolar outflows are present in many disk-accreting astrophysical systems. Indisk-accreting cataclysmic variables (CVs), these outflows are responsible formost of the strong features in the ultraviolet spectra of these systems.However, there have been few attempts to model these features quantitatively.Here, we describe a new, hybrid Monte Carlo/Sobolev code, which allows us tosynthesize the complete spectrum of a disk-dominated, mass-losing CV. The line profiles we calculate for C IV resemble those calculated by previousworkers when an identical geometry is assumed. However, our synthetic spectraexhibit not only the well-known resonance lines of O VI, N V, Si IV and C IV,but, with an appropriate choice of mass-loss rate and wind geometry, also manylines originating from excited lower states. Many of these lines have alreadybeen seen in the far ultraviolet spectra of CVs obtained with HUT, FUSE, andHST. In order to illustrate the degree to which we are currently able toreproduce observed spectra, we finally present a preliminary fit to the HopkinsUltraviolet Telescope spectrum of the dwarf nova Z Cam in outburst.Comment: 41 pages, 9 figures, to be published in Ap