Gravitational-wave constraints on the GWTC-2 events by measuring the tidal deformability and the spin-induced quadrupole moment

TL;DR

This paper reanalyzes GWTC-2 gravitational wave events to constrain the tidal deformability and spin-induced quadrupole moments, testing whether the sources are consistent with binary black holes in general relativity.

Contribution

It provides model-independent constraints on deviations from binary black holes by focusing on inspiral waveform properties, excluding merger and ringdown regimes.

Findings

All analyzed events are consistent with binary black hole waveforms.

Exotic compact object hypotheses are disfavored by Bayesian model selection.

Constraints on tidal deformability and quadrupole moments support general relativity predictions.

Abstract

Gravitational waves from compact binary coalescences provide a unique laboratory to test properties of compact objects. As alternatives to the ordinary black holes in general relativity, various exotic compact objects have been proposed. Some of them have largely different values of the tidal deformability and spin-induced quadrupole moment from those of black holes, and their binaries could be distinguished from the binary black hole by using gravitational waves emitted during their inspiral regime, excluding the highly model-dependent merger and ringdown regimes. We reanalyze gravitational waves from low-mass merger events in the GWTC-2, detected by the Advanced LIGO and Advanced Virgo. Focusing on the influence of tidal deformability and spin-induced quadrupole moment in the inspiral waveform, we provide model-independent constraints on deviations from the standard binary black hole case. We find that all events that we have analyzed are consistent with the waveform of the binary black hole in general relativity. Bayesian model selection shows that the hypothesis that the binary is composed of exotic compact objects is disfavored by all events.