Quasinormal modes of Kerr-like black bounce spacetime

We investigate the quasinormal mode (QNM) spectrum of a Kerr-like black-bounce spacetime under massive scalar-field perturbations. Starting from the Kerr-like deformation of the Simpson--Visser black-bounce geometry, we derive the corresponding radial and angular equations and obtain the effective potential governing scalar perturbations. The QNM frequencies are computed by means of the Pöschl–Teller potential approximation and the semi-analytic WKB method (up to sixth order), and we demonstrate reasonable agreement between these two approaches. We then analyze in detail how the QNM spectrum depends on the spin parameter a, the bounce parameter p that interpolates between black-hole and wormhole geometries, and the scalar-field mass μ. Our results show that increasing the spin parameter a raises the oscillation frequency, while increasing the bounce parameter p lowers it, and in both cases the damping rate decreases. Moreover, the mass of the scalar field has a non-negligible impact on the ringdown spectrum. These features suggest that rotating black-bounce geometries may leave distinct imprints in the ringdown phase of gravitational-wave signals, and motivate future studies of echoes and parameter estimation in the context of present and upcoming detectors.