Accurate effective-one-body waveforms of inspiralling and coalescing black-hole binaries

The effective-one-body (EOB) formalism contains several flexibility parameters, notably a₅, v₏₎₋₄, and aₑₑ. We show here how to jointly constrain the values of these parameters by simultaneously best-fitting the EOB waveform to two, independent, numerical relativity (NR) simulations of inspiralling and/or coalescing binary black-hole systems: published Caltech-Cornell inspiral data (considered for gravitational wave frequencies M0. 1) on one side, and newly computed coalescence data on the other side. The resulting, approximately unique, ``best-fit'' EOB waveform is then shown to exhibit excellent agreement with NR coalescence data for several mass ratios. The dephasing between this best-fit EOB waveform and published Caltech-Cornell inspiral data is found to vary between -0. 0014 and +0. 0008 radians over a time span of 2464M up to gravitational wave frequency M=0. 1, and between +0. 0013 and -0. 0185 over a time span of 96M after M=0. 1 up to M=0. 1565. The dephasings between EOB and the new coalescence data are found to be smaller than: (i) 0. 025 radians over a time span of 730M (11 cycles) up to merger, in the equal-mass case, and (ii) 0. 05 radians over a time span of about 950M (17 cycles) up to merger in the 2: 1 mass-ratio case. These new results corroborate the aptitude of the EOB formalism to provide accurate representations of general relativistic waveforms, which are needed by currently operating gravitational wave detectors.