München 2009 – scientific programme
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GR: Fachverband Gravitation und Relativitätstheorie
GR 9: Numerische Relativitätstheorie I
GR 9.1: Talk
Thursday, March 12, 2009, 11:45–12:05, A214
Using curvature invariants for wave extraction in numerical relativity — •Oliver Elbracht1 and Andrea Nerozzi2 — 1Institut für Theoretische Physik und Astrophysik, Julius-Maximilians-Universität, Am Hubland, 97074 Würzburg, Germany — 2Institut für Angewandte Mathematik, Friedrich-Schiller-Universität, Ernst-Abbe-Platz 2, 07743 Jena, Germany
We present a new expression for the Weyl scalar Ψ4 that can be used in numerical relativity to extract the space-time gravitational wave content. The formula relies upon the identification of transverse tetrads, namely the ones in which Ψ1=Ψ3=0. It is well known that tetrads with this property always exist in a general Petrov type I space-time. A sub-class of these tetrads naturally converges to the Kinnersley tetrad in the limit of Petrov type D space-time. However, the transverse condition fixes only four of the six parameters coming from the Lorentz group of transformations applied to tetrads. Here we fix the tetrad completely, in particular by giving the expression for the spin-boost transformation that was still unclear. The value of Ψ4 in this optimal tetrad is given as a simple function of the two curvature invariants I and J.