We present a new method for finding principal null directions (PNDs). Because our method assumes as an input the intrinsic metric and extrinsic curvature of a space-like hypersurface, we expect it will be useful to numerical relativists. We illustrate our method by finding the PNDs of the Kastor - Traschen spacetimes, which contain arbitrarily many Q=M black holes in a de Sitter background.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)