Assessing the compact-binary merger candidates reported by the MBTA pipeline in the LIGO-Virgo O3 run: probability of astrophysical origin, classification, and associated uncertainties

Understand

We describe the method used by the Multi-Band Template Analysis (MBTA) pipeline to compute the probability of astrophysical origin, $p_{astro}$, of compact binary coalescence candidates in LIGO-Virgo data from the third observing run (O3).

• The calculation is performed as part of the offline analysis and is used to characterize candidate events, along with their source classification.
• The technical details and the implementation are described, as well as the results from the first half of the third observing run (O3a) published in GWTC-2.1.
• The performance of the method is assessed on injections of simulated gravitational-wave signals in O3a data using a parameterization of $p_{astro}$ as a function of the MBTA combined ranking statistic.