Non-Kerr constraints using binary black hole inspirals considering phase modifications up to 4 PN order

Debtroy Das; Swarnim Shashank; Cosimo Bambi

doi:10.1140/epjc/s10052-024-13623-7

2024 Impact factor 4.8

Particles and Fields

Open Access

Eur. Phys. J. C (2024) 84: 1237
https://doi.org/10.1140/epjc/s10052-024-13623-7

Regular Article

Non-Kerr constraints using binary black hole inspirals considering phase modifications up to 4 PN order

Debtroy Das¹, Swarnim Shashank¹ and Cosimo Bambi¹^,2^a

¹ Center for Astronomy and Astrophysics, Center for Field Theory and Particle Physics, and Department of Physics, Fudan University, 200438, Shanghai, China
² School of Natural Sciences and Humanities, New Uzbekistan University, 100007, Tashkent, Uzbekistan

^a bambi@fudan.edu.cn

Received: 24 August 2024
Accepted: 17 November 2024
Published online: 29 November 2024

Abstract

The gravitational field around an astrophysical black hole (BH) is thought to be described by the Kerr spacetime, which is a solution of the Einstein equation. Signatures of binary black hole (BBH) coalescence in gravitational waves (GW) follow the Kerr spacetime as the theoretical foundation. Hence, any possible deviations from the Kerr spacetime around BHs serve as a test of the nature of gravity in the strong-field regime and of the predictions of General Relativity. In our study, we perform a theory-agnostic test of the Kerr hypothesis using BBH inspirals from the third Gravitational-wave Transient Catalog (GWTC-3). Considering the Johannsen metric, we compute the leading-order deviation to the emitted GW in the frequency domain. Our results provide constraints on two deformation parameters ( $α_{13}$ $\alpha _{13}$ and $ϵ_{3}$ $\epsilon _3$ ) and demonstrate the degeneracy between these two non-Kerr parameters.

Supplementary Information The online version contains supplementary material available at https://doi.org/10.1140/epjc/s10052-024-13623-7.

© The Author(s) 2024

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