Perturbative calculation of quasi-normal modes of AdS Schwarzschild   black holes
  We calculate analytically quasi-normal modes of AdS Schwarzschild black holes including first-order corrections. We consider massive scalar, gravitational and electromagnetic perturbations. Our results are in good agreement with numerical calculations. In the case of electromagnetic perturbations, ours is the first calculation to provide an analytic expression for quasi-normal frequencies, because the effective potential vanishes at zeroth order. We show that the first-order correction is logarithmic. 
Suphot Musiri, Scott Ness, George Siopsis