Line Profiles from Different Accretion Engine Geometries
  Line profiles represent an important probe of the geometry and dynamics of the central accretion engines in AGN. Although a flat disk illuminated from above can explain the relativistic Fe K alpha line profile in some cases, current data, plausible disk physics, and future comparison to the iron and other AGN lines invite some consideration of other geometries. General features of line profiles calculated fom concave discs, warped discs, thick clumpy (inflow/outflow) discs, and disks with spiral structure, are briefly summarized. 
Eric G. Blackman (Univ. of Rochester), Sean A. Hartnoll (Cambridge)