The Electromagnetic Signature of Black Hole Ring‐Down

We investigate generation of electromagnetic radiation by gravitational wavesinteracting with a strong magnetic field in the vicinity of a vibratingSchwarzschild black hole. Such an effect may play an important role ingamma-ray bursts and supernovae, their afterglows in particular. It may alsoprovide an electromagnetic counterpart to gravity waves in many situations ofinterest, enabling easier extraction and verification of gravity wave waveformsfrom gravity wave detection. We set up the Einstein-Maxwell equations for thecase of odd parity gravity waves impinging on a static magnetic field as acovariant and gauge-invariant system of differential equations which can beintegrated as an initial value problem, or analysed in the frequency domain. Wenumerically investigate both of these cases. We find that the black holeringdown process can produce substantial amounts of electromagnetic radiationfrom a dipolar magnetic field in the vicinity of the photon sphere.Comment: 21 pages, 4 figures; AASTeX; v3 to match version to appear in Ap