Quasi-Normal Oscillations of a Black Hole with Deficit Angle for Electromagnetic Perturbations

We consider an electromagnetic perturbation in the external space-time of a black hole with deficit angle, and describe the perturbation equation. Approximate analytic formulas for the quasi-normal frequencies have been provided, which may play a significant role in the continuing search for gravitational radiation and black hole. These frequencies can be distinguished from the ordinary quasi-normal frequencies of Schwarzschild black hole.