Quasinormal ringing of Kerr black holes. II. Excitation by particles falling radially with arbitrary energy

Understand

The analytical understanding of quasinormal mode ringing requires an accurate knowledge of the Green's function describing the response of the black hole to external perturbations.

• We carry out a comprehensive study of quasinormal mode excitation for Kerr black holes.
• Relying on the formalism developed by Mano, Suzuki and Takasugi, we improve and extend previous calculations of the quasinormal mode residues in the complex frequency plane ("excitation factors" B_q).
• Using these results we compute the "excitation coefficients" C_q (essentially the mode amplitudes) in the special case where the source of the perturbations is a particle falling into the black hole along the symmetry axis.