Late-time behavior of stellar collapse and explosions. II. Nonlinear evolution

We compare the predictions of linearized theory for the radiation produced in the collapse of a spherically symmetric scalar field with a full numerical integration of the Einstein equations. We find power-law tails and quasinormal ringing remarkably similar to predictions of linearized theory even in cases where nonlinearities are crucial. We also show that power-law tails develop even when the collapsing scalar field fails to produce a black hole.