Searching for Gravitational Waves from the Inspiral of Precessing Binary Systems: Astrophysical Expectations and Detection Efficiency of "Spiky'' Templates

TL;DR

This paper investigates how precession effects in inspiraling black hole-neutron star binaries affect gravitational wave detection, showing that neglecting precession can lead to a 20-30% loss in detection efficiency, and assesses the robustness of waveform models.

Contribution

It evaluates the impact of precession on gravitational wave detection efficiency and demonstrates that approximate waveform techniques are sufficient for reliable sensitivity estimates.

Findings

Detection loss due to precession is within 20-30%.

Approximate waveform models agree well with full 2PN integrations.

Large tilt angles are astrophysically unlikely, reducing detection loss.

Abstract

Relativistic spin-orbit and spin-spin couplings has been shown to modify the gravitational waveforms expected from inspiraling binaries with a black hole and a neutron star. As a result inspiral signals may be missed due to significant losses in signal-to-noise ratio, if precession effects are ignored in gravitational-wave searches. We examine the sensitivity of the anticipated loss of signal-to-noise ratio on two factors: the accuracy of the precessing waveforms adopted as the true signals and the expected distributions of spin-orbit tilt angles, given the current understanding of their physical origin. We find that the results obtained using signals generated by approximate techniques are in good agreement with the ones obtained by integrating the 2PN equations. This shows that a complete account of all high-order post-Newtonian effects is usually not necessary for the determination of detection efficiencies. Based on our current astrophysical expectations, large tilt angles are not favored and as a result the decrease in detection rate varies rather slowly with respect to the black hole spin magnitude and is within 20--30% of the maximum possible values.