Constraining the Konoplya-Rezzolla-Zhidenko deformation parameters III: limits from stellar-mass black holes using gravitational-wave observations

TL;DR

This paper uses gravitational-wave data from 29 binary black hole events to test the Kerr hypothesis and constrain specific deformation parameters of non-Kerr black hole spacetimes, finding results consistent with Kerr.

Contribution

It provides the first constraints on two deformation parameters ($oldsymbol{ extdelta_1}$ and $oldsymbol{ extdelta_2}$) using gravitational-wave observations, improving upon previous X-ray based limits.

Findings

All events are consistent with the Kerr hypothesis.

Stronger constraints on $oldsymbol{ extdelta_1}$ and $oldsymbol{ extdelta_2}$ than previous X-ray studies.

Cannot constrain other deformation parameters ($oldsymbol{ extdelta_3}$ to $oldsymbol{ extdelta_6}$).

Abstract

Gravitational-wave observations of binary black holes provide a suitable arena to test the fundamental nature of gravity in the strong-field regime. Using the data of the inspiral of 29 events detected by the LIGO-Virgo observatories, we perform a theory-agnostic test of the Kerr hypothesis. We compute the leading-order deviation to the gravitational waves emitted in the frequency domain and provide constraints on two deformation parameters ($\delta_1$ and $\delta_2$) belonging to a general class of axisymmetric non-Kerr black hole spacetimes proposed by Konoplya, Rezzolla & Zhidenko. Our study shows that all the analyzed events are consistent with the Kerr hypothesis. The LIGO-Virgo data provide stronger constraints on $\delta_1$ and $\delta_2$ than those obtained in our previous studies with X-ray data (Papers I and II), while, on the other hand, they cannot constrain the other deformation parameters of the Konoplya-Rezzolla-Zhidenko metric ($\delta_3$, $\delta_4$, $\delta_5$, and $\delta_6$).