Intermediate Mass Ratio Black Hole Binaries: Numerical Relativity meets Perturbation Theory

We study black-hole binaries in the intermediate-mass-ratio regime 0.01 < q < 0.1 with a new technique that makes use of nonlinear numerical trajectories and efficient perturbative evolutions to compute waveforms at large radii for the leading and nonleading modes. As a proof-of-concept, we compute waveforms for q=1/10. We discuss applications of these techniques for LIGO/VIRGO data analysis and the possibility that our technique can be extended to produce accurate waveform templates from a modest number of fully-nonlinear numerical simulations.Comment: 4 pages, 5 figures, revtex

Comparison of Post-Newtonian and Numerical Evolutions of Black-Hole Binaries

In this paper, we compare the waveforms from the post-Newtonian (PN) approach with the numerical simulations of generic black-hole binaries which have mass ratio $q\sim0.8$, arbitrarily oriented spins with magnitudes $S_1/m_1^2\sim0.6$ and $S_2/m_2^2\sim0.4$, and orbit 9 times from an initial orbital separation of $r\approx11M$ prior to merger. We observe a reasonably good agreement between the PN and numerical waveforms, with an overlap of over 98% for the first six cycles of the $(\ell=2,m=\pm2)$ mode and over 90% for the $(\ell=2,m=1)$ and $(\ell=3,m=3)$ modes.Comment: 4 pages, 2 figures, prepared for the proceedings of the 18th workshop on general relativity and gravitation, Hiroshima, Japan, Nov.17 - Nov.21, 200

New method to integrate 2+1 wave equations with Dirac's delta functions as sources

Gravitational perturbations in a Kerr black hole background can not be decomposed into simple tensor harmonics in the time domain. Here, we make the mode decomposition only in the azimuthal direction and discuss the resulting (2+1)-dimensional Klein-Gordon differential equation for scalar perturbations with a two dimensional Dirac's $\delta$-function as a source representing a point particle orbiting a much larger black hole. To make this equation amenable for numerical integrations we explicitly remove analytically the singular behavior of the source and compute a global effective source for the corresponding waveform.Comment: 4 pages, 1 figure, prepared for the proceedings of the 17th workshop on general relativity and gravitation, Nagoya, Japan, Dec.3 - Dec.7, 200

Perturbative effects of spinning black holes with applications to recoil velocities

Recently, we proposed an enhancement of the Regge-Wheeler-Zerilli formalism for first-order perturbations about a Schwarzschild background that includes first-order corrections due to the background black-hole spin. Using this formalism, we investigate gravitational wave recoil effects from a spinning black-hole binary system analytically. This allows us to better understand the origin of the large recoils observed in full numerical simulation of spinning black hole binaries.Comment: Proceedings of Theory Meets Data Analysis at Comparable and Extreme Mass Ratios (NRDA/Capra 2010), Perimeter Institute, June 2010 - 12 page