When will we observe binary black holes precessing?
Abstract
After eleven gravitationalwave detections from compactbinary mergers, we are yet to observe the striking generalrelativistic phenomenon of orbital precession. Measurements of precession would provide valuable insights into the distribution of blackhole spins, and therefore into astrophysical binary formation mechanisms. Using our recent twoharmonic approximation of precessingbinary signals~\cite{Fairhurst:2019_2harm}, we introduce the ``precession signaltonoise ratio'', $\rho_p$. We demonstrate that this can be used to clearly identify whether precession was measured in an observation (by comparison with both current detections and simulated signals), and can immediately quantify the measurability of precession in a given signal, which currently requires computationally expensive parameterestimation studies. $\rho_p$ has numerous potential applications to signal searches, sourceproperty measurements, and population studies. We give one example: assuming one possible astrophysical spin distribution, we predict that precession has a one in $\sim 25$ chance of being observed in any detection.
 Publication:

arXiv eprints
 Pub Date:
 August 2019
 arXiv:
 arXiv:1908.00555
 Bibcode:
 2019arXiv190800555F
 Keywords:

 General Relativity and Quantum Cosmology
 EPrint:
 5 pages, 2 Figures