Gravitational-wave propagation on Kerr spacetime: A spin wave optics approach

Abstract:

Gravitational-wave observations offer new opportunities to study wave propagation in the strong gravitational fields of black holes. Near a rotating black hole, this propagation involves both wave effects and interactions between the spin-2 nature of gravitational waves and the background curvature. After a brief introduction to the Teukolsky formalism, I will discuss gravitational waves from a localized source lensed by a Kerr black hole, focusing on helicity-dependent features in the amplification spectrum. I will also discuss possible connections with resonant excitation of quasinormal modes.

References:

[1] K. Kubota, S. Arai, H. Motohashi, and S. Mukohyama, Phys. Rev. D 110, 124011 (2024), [arXiv:2408.03289].

[2] H. Motohashi, Phys. Rev. Lett. 134, 141401 (2025), [arXiv:2407.15191].



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