2002/06/30 by Olaf Dreyer, B. Krishnan, Badri Krishnan +3 · 14 citations
Mathematics · Physics and Astronomy · #Angular momentum #Apparent horizon #Astrophysical Phenomena and Observations #Black Holes and Theoretical Physics #Black hole (networking) #Classical mechanics #Computer science #Delta #Event horizon #General relativity #Geometry #Horizon #Mathematical physics #Mathematics #Mechanics #Numerical relativity #Physics #Pulsars and Gravitational Waves Research #Symmetry (geometry) #Vector field #gr-qc
paper · pdf · doi:10.1103/physrevd.67.024018
published as Phys.Rev.D67:024018,2003 · 14 pages, revtex4, 7 figures. Final PRD version
openalex publication_date 2003/01/17 · arxiv created 2004/01/11 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present a coordinate-independent method for extracting the mass (M_\ensuremathΔ) and angular momentum (J_\ensuremathΔ) of a black hole in numerical simulations. This method, based on the isolated horizon framework, is applicable both at late times when the black hole has reached equilibrium, and at early times when the black holes are widely separated. Assuming that the spatial hypersurfaces used in a given numerical simulation are such that apparent horizons exist and have been located on these hypersurfaces, we show how J_\ensuremathΔ and M_\ensuremathΔ can be determined in terms of only those quantities which are intrinsic to the apparent horizon. We also present a numerical method for finding the rotational symmetry vector field (required to calculate J_\ensuremathΔ) on the horizon.