Speaker: Sarp Akcay (University Coll., Dublin)
Title: Precession in Stellar-mass Compact Binary Inspirals
Abstract: I first discuss how precessing waveform approximants are generated for LIGO-Virgo parameter estimation. I then introduce a new such approximant called TEOBResumSP that my collaborators and I have been developing. TEOBResumSP is an efficient hybrid scheme for generating precessing gravitational waveforms that combines post-Newtonian precession equations with effective-one-body aligned-spin dynamics. The approach Euler-rotates aligned-spin TEOBResumS waveforms from a precessing frame to an inertial frame via Wigner's D matrices. The scheme is compared to current state-of-the-art precessing approximants NRSurd74q and SEOBNRv4PHM in terms of frequency-domain matches of the $\el=2$ gravitational-wave strain for approximately 1300 compact binary inspirals with the initial gravitational-wave frequencies between 20 and 50 Hz and the precessing spin parameter $\chi_p$ ranging up to one. The matches are better than 0.965 for 85% of the NRSurd74q comparisons and 75% of the SEOBNRv4PHM set. The largest disagreements occur for large mass ratios and for large spin components along the orbital plane quantified in terms of a new parameter, $\Sperp$, that I introduce. The disagreements stem from Euler-rotating non-precessing waveforms with constant spins, which can be replaced by time-varying z-components of spins. TEOBResumSP provides a robust alternative precessing approximant to be employed in the parameter estimation of generic-spin compact binaries.
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