Moving black holes in 3D

We model a radiating, moving black hole in terms of a worldtube–null-cone boundary value problem. We evolve this data in the region interior to the worldtube, but exterior to a trapped surface by means of a characteristic evolution based upon a family of ingoing null hypersurfaces. Data on the worldtube is induced from a Schwarzschild spacetime, but the worldtube is allowed to move relative to the static Schwarzschild trajectories. When the worldtube is stationary ~static or rotating in place!, a distorted black hole inside it evolves to equilibrium with the Schwarzschild boundary. A boost of the worldtube with respect to the Schwarzschild black hole does not affect these results. The code also stably tracks an unlimited number of orbits, when the worldtube wobbles periodically. The work establishes that characteristic evolution can evolve a spacetime with a distorted black hole moving on a 3-dimensional grid with the controlled accuracy and long term stability necessary to investigate new facets of black hole physics. @S0556-2821~98!00310-5#