Collision of spinning black holes in the close limit

In this paper we consider the collision of spinning holes using first order perturbation theory of black holes (Teukolsky formalism). With these results (along with ones, we published in the past) one can predict the properties of the gravitational waves radiated from the late stage inspiral of two spinning, equal mass black holes. Also we note that the energy radiated by the head-on collision of two spinning holes with spins (that are equal and opposite) aligned along the common axis is more than the case in which the spins are perpendicular to the axis of the collision.