15th Capra Meeting on Radiation Reaction in General Relativity

Fast waveform extraction from gravitational perturbations

Scott Field

University of Maryland
[SLIDES]

Numerical simulation of blackhole perturbations on a finite computational domain requires the introduction of a fictitious outer boundary. On this surface we seek to i) supply exact radiation boundary conditions and ii) extract the asymptotic waveform which would reach null infinity. We show how each task is easily handled via a time-domain convolution of the perturbations recorded at the outer boundary with a small number of damped exponentials. We briefly motivate the origin of this convolution by analogy to the ordinary 3+1 wave equation. Our technique is easy to implement (from the user's standpoint), affords high accuracy, and works for both axial (Regge-Wheeler) and polar (Zerilli) perturbations. A brief discussion of results will also be presented.