When a pair of black holes spiral into each other and collide, the very fabric of space-time shakes, and gravitational waves are created. Gravitational waves carry information about their source, and will increase our understanding of relativistic systems in astrophysics. Gravitational wave observatories like LIGO and Virgo are tuned to detect the emission of these waves from the inspiral and merger of binary black holes, neutron stars, supernovae, etc…
Problem: any small vibration is detected, so templates are essential to discern the real signal. It is hard to compute the waveforms obtained from numerical simulations accurately – gravitational radiation is properly defined only at null infinity, but is estimated at a finite radius.
Cauchy-Characteristic Extraction (CCE) is the most precise and refined “extraction” method available. The CCE technique connects the strong-field “Cauchy” evolution of the space-time near the merger to the “characteristic” evolution far from the merger – at null infinity, where the waveform is extracted and detectors measure it. We present a stand-alone “characteristic” waveform extraction tool that has demonstrated accuracy and convergence of the numerical error and is used by the numerical relativity groups for the unambiguous extraction of waveforms. We prove that the numerical error of CCE satisfies the standards of the detection criteria required for Advanced LIGO data analysis. The tool provides a means for accurate calculation of waveforms generated by evolution codes based upon different analytic and numerical formulations of the Einstein equations.
Babiuc-Hamilton, M. (2012, June). Gravitational-waveform extraction by the characteristic method. Poster session presented at the 220th AAS Meeting, Anchorage, AK.