Profiles and Polarization Properties of Emission Lines from Relativistic   Disks
  We examined the profiles and polarization properties of emission lines originating from the extremely relativistic region of Kepler disks.   Because the emission region is more localized to the inner part, e.g., a few times the black hole radius, the profiles, and polarization properties are remarkably modified. The black hole spin significantly affects the properties through the inner edge. This observation, in spite of the technical difficulties, provides an important diagnostic of the relativistic region. 
Jun Ogura, Nobuyori Ohuo and Yasufumi Kojima