Late-time decay of scalar perturbations outside rotating black holes

We present an analytic method for calculating the late-time tails of a line ar scalar held outside a Kerr black hole. We give the asymptotic behavior a t timelike infinity (for fixed r), at future null-infinity, and along the e vent horizon (EH). In all three asymptotic regions we find a power-law deca y. We show that the power indices describing the decay of the various modes at fixed r differ from the corresponding Schwarzschild values. Also, the s calar field oscillates along the null generators of the EH (with advanced-t ime frequency proportional to the mode's magnetic number m). [S0031-9007(99 )09261-3].