Search Talks

In this talk I will show recent results obtained by the RIT group fromsimulations of highly-spinning binaries including new data that givesnear maximal spins and high-mass ratio binaries. Simulations in bothof these regimes are numerically challenging. However asastrophysical binaries are expected to be highly-spinning and havehigh mass ratios accurate simulations in these regimes are crucialfor understanding the dynamics of realistic binaries.

The initial gold rush of exploration into new regions of parameter space has slowed significantly. While our ability to simulate larger spins and more extreme mass ratios has continued to improve, much of the recent progress in numerical relativity has centered on improvements in methodology, in condensing and interpreting an ever-growing body of numerical results, and in incorporating matter into the numerical simulations. In this review, I will summarize the recent progress in this field, focusing on novel results in the simulation of black hole binaries, with some discussion of novel applications of those results to data analysis.

Recent progress in numerical- and analytical relativity enables us to construct analytical waveform templates coherently describing the inspiral, merger and ring down of coalescing black-hole binaries. Such waveform templates not only improve the sensitivity of the searches for gravitational waves from high-mass binaries significantly, but also the accuracy of the parameter estimation. This talk summarizes the status and prospects of different approaches of the modeling of gravitational waveform from binary black holes calibrated to numerical- relativity simulations.

With several ground-based gravitational wave interferometers operating at design sensitivity the need for high-order post-Newtonian (PN) calculations of potentials waveforms etc. especially including spin effects has grown significantly over the last several years. Not only are these calculations necessary for precisely estimating the parameters of detected gravitational wave sources but they are also useful for providing more accurate models of binary evolutions in for example the effective one-body program and for computing the PN contributions to self-force effects in the extreme mass ratio limit. Since these calculations become more demanding to carry out at higher PN orders it is necessary to utilize symbolic computer algebra programs (such as Mathematica). Our aim is to automate PN calculations (of potentials power loss etc.) on the computer using the effective field theory (EFT) approach of Goldberger and Rothstein which is itself a systematic and algorithmic method for computing in the PN approximation. The EFT approach lends itself to automation through definite power counting rules that identify precisely those interactions appearing at a given PN order through Feynman rules and diagrams that provide an elegant way to side-step the need to explicitly solve the wave equation for metric perturbations (unlike in traditional methods) through working at the level of the action (a scalar) instead of equations of motion etc. We discuss our progress in automating these calculations on a computer using the EFT approach.