Exact solution for wave scattering from black holes: Formulation

We establish an exact formulation forwave scattering of a massless field with spin and charge by a Kerr-Newman-de Sitter black hole. Our formulation is based on the exact solution of the Teukolsky equation in terms of the local Heun function, and does not require any approximation. It serves as simple exact formulae with arbitrary high precision, which realize fast calculation without restrictions on model parameters. We highlight several applications including quasinormal modes, cross section, reflection/absorption rate, and Green function.