EVOLUTION OF DISTORTED ROTATING BLACK-HOLES .1. METHODS AND TESTS

We have developed a new numerical code to study the evolution of disto rted, rotating black holes. We discuss the numerical methods and gauge conditions we developed to evolve such spacetimes. The code has been put through a series of tests and we report on (a) results of comparis ons with codes designed to evolve nonrotating holes, (b) the evolution of Kerr spacetimes for which analytic properties are known, and (c) t he evolution of distorted rotating holes. The code accurately reproduc es results of the previous NCSA nonrotating code and passes convergenc e tests. New features of the evolution of rotating black holes not see n in nonrotating holes are identified. With this code we can evolve ro tating black holes up to about t = 100M, depending on the resolution a nd angular momentum. We also describe a new family of black hole initi al data sets which represent rotating holes with a wide range of disto rtion parameters, and distorted nonrotating black holes with odd-parit y radiation. Finally, we study the limiting slices for a maximally sli ced rotating black hole and find good agreement with theoretical predi ctions.