Resonant bound orbits and kludge waveforms in rotating Konoplya-Zhidenko black hole spacetime

Abstract

We investigate timelike bound motion, resonant periodic orbits, and their gravitational-wave signatures in the rotating Konoplya-Zhidenko (KZ) black hole spacetime. Using the separability of the Hamilton-Jacobi equation, we parameterize eccentric and inclined bound orbits by $(p,e,z_1)$, derive the corresponding constants of motion $(E,L_z,Q)$, and use the orbital frequencies to identify resonant configurations. We study a range of resonances, including radial-polar resonances of inclined orbits and radial-azimuthal resonances of equatorial eccentric orbits. We further construct physically scaled quadrupole-kludge waveforms for representative equatorial resonant orbits and analyze their frequency-domain characteristics. Our results show that the KZ deformation shifts the resonance locations and modifies both the orbital trajectories and the resulting gravitational-wave signals. The corresponding characteristic strain lies predominantly in the millihertz band, placing these signals in the frequency range relevant to space-based gravitational wave detectors.