Hybrid post-Newtonian effective-one-body scheme for spin-precessing compact-binary waveforms up to merger

We introduce TEOBResumSP: an efficient yet accurate hybrid scheme for generating gravitational waveforms from spin-precessing compact binaries. The precessing waveforms are generated via the established technique of Euler rotating aligned-spin (nonprecessing) waveforms from a precessing frame to an inertial frame. We employ the effective-one-body approximant TEOBResumS to generate the aligned-spin waveforms. We obtain the Euler angles by solving the post-Newtonian precession equations expanded to (next−to) 4 leading (second post-Newtonian) order. Current version of TEOBResumSP produces precessing waveforms through the inspiral phase up to the onset of the merger. We compare TEOBResumSP to current state-of-the-art precessing approximants NRSur7dq4, SEOBNRv4PHM, and IMRPhenomPv3HM in terms of frequency-domain matches of the ℓ=2 gravitational-wave strain for 200 cases of precessing compact binary inspirals with orbital inclinations up to 90 degrees, mass ratios up to four, and the effective precession parameter χp up to 0.75. We further provide an extended comparison with SEOBNRv4PHM involving 1030 more inspirals with χp ranging up to one and mass ratios up to 10. We find that 91% of the TEOBResumSP-NRSur7dq4 matches, 85% of the TEOBResumSP SEOBNRv4PHM matches, and 77% of the TEOBResumSP-IMRPhenomPv3HM matches are greater than 0.965. Most of the significant disagreements occur for large mass ratios and χp≳0.6. We identify the mismatch of the non-precessing (2,1) mode as one of the leading causes of disagreements. We also introduce a new parameter, χ⊥, max, to measure the strength of precession and hint that the strain mismatch between the above waveform approximants shows an exponential dependence on χ⊥,max though this requires further study. Our results indicate that TEOBResumSP is on its way to becoming a robust precessing approximant to be employed in the parameter estimation of generic-spin compact binaries.