J. Finke & M. Böttcher
in proc. of ``HEDLA 2006''
Astrophysics & Space Science, 297, 325 (2007)
The nature of Ultraluminous X-ray Sources - X-ray sources which exceed the Eddington luminosity for a ~ 10 solar-mass black hole - remains a mystery. One possible explanation is an inhomogeneous accretion disk around a solar-mass black hole where photon transport through radiation-pressure dominated ``photon bubbles'' can lead to super-Eddington accretion. While previous studies of this model have focused primarily on its radiation-hydrodynamics aspects, here we explore some observational implications of such a model with a Monte-Carlo - Fokker-Planck radiation transport code.