New black hole mergers in the LIGO-Virgo O3 data from a gravitational wave search including higher-order harmonics

Understand

Nearly all of the previous gravitational wave (GW) searches in the LIGO-Virgo data included GW waveforms with only the dominant quadrupole harmonic, i.e., omitting higher-order harmonics which are predicted by general relativity.

• We improved the IAS pipeline by efficiently introducing higher harmonics in the GW templates using the techniques in Wadekar et al.
• [1, 2].
• Using the IAS-HM pipeline on the public LIGO-Virgo data from the O3 run, we find 11 new candidate BBH mergers with $0.52\leq p_\mathrm{astro}\leq 0.88$ (we use the detection threshold as the astrophysical probability, $p_\mathrm{astro}$, being over 0.5, following the approach of other pipelines).