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Abstract

The detection of gravitational waves and the extraction of physical
information from them requires the prediction of accurate waveforms to be used
in template banks. For that purpose, the accuracy of effective-one-body (EOB)
waveforms has been improved over the last years by calibrating them to
numerical-relativity (NR) waveforms. So far, the calibration has employed a
handful of NR waveforms with a total length of ~30 cycles, the length being
limited by the computational cost of NR simulations. Here we address the
outstanding problem of the stability of the EOB calibration with respect to the
length of NR waveforms. Performing calibration studies against NR waveforms of
nonspinning black-hole binaries with mass ratios 1, 1.5, 5, and 8, and with a
total length of ~60 cycles, we find that EOB waveforms calibrated against
either 30 or 60 cycles will be indistinguishable by the advanced detectors LIGO
and Virgo when the signal-to-noise ratio (SNR) is below 110. When extrapolating
to a very large number of cycles, using very conservative assumptions, we can
conclude that state-of-the-art nonspinning EOB waveforms of any length are
sufficiently accurate for parameter estimation with advanced detectors when the
SNR is below 20, the mass ratio is below 5 and total mass is above 20 Msun. The
results are not conclusive for the entire parameter space because of current NR
errors.