Photon Emission Near Extreme Kerr Black Holes
  Ongoing astronomical efforts extract physical properties of black holes from electromagnetic emissions in their near-vicinity. This requires finding the null geodesics which extend from the near-horizon region out to a distant observatory. In general these can only be found numerically. In this paper, for the interesting special case of extremally spinning Kerr black holes, we use an emergent near-horizon conformal symmetry to find near-superradiant geodesics analytically. 
Achilleas P. Porfyriadis, Yichen Shi and Andrew Strominger
gr-qc astro-ph.HE hep-th