Using Polarization Spectra as a Measure of Disk Thickness in Black Hole Systems

The Standard Model of Black Hole Accretion Disks consists of a geometrically thin, optically thick disk whose inner edge truncates at the ISCO. While this model is widely used and can describe a large body of observational data, it is limited to systems with an accretion rate above a few percent and below a few tens of percent of the Eddington Limit. At lower and higher accretion rates, accretion disks are thought to be geometrically thick. I present here a phenomenological model of a toroidal accretion disk and will discuss the results of a raytracing study completed on this model for accretion rates below a few percent and above 30% of the Eddington limit. In particular, I will review the effect that this geometry has on the thermal polarization spectra, Iron line profile, and reverberation signatures of black hole systems, and whether these signatures may provide a means of estimating disk thickness within the observational bounds of the next generation X-Ray polarimetry missions, the Imaging X-Ray Polarimetry Explorer (IXPE) and XL-Calibur.