2026/07/24 by Abdelmalek Bouzenada, Orhan Donmez, Imran Shakir +3
paper · doi:10.1142/s0219887826503068
In this paper, we conduct a comprehensive analysis of test particle dynamics measurements in the spacetime of slowly rotating disformal Kerr black hole (BH) models. Also, the characteristics of circular motion near these BHs are systematically investigated, and the corresponding effective potential is computed to assess the stability of particle orbits under various disformal parameter regimes. Linear perturbations around stable circular trajectories are introduced to derive the harmonic oscillation frequencies, which are subsequently expressed in terms of measurements by distant static observers. Also, the impact of the disformal deformation on orbital stability, radial and vertical epicyclic frequencies, and potential astrophysical observables is rigorously quantified. In this context, our analysis demonstrates that even minor departures from the standard Kerr geometry induce measurable modifications in orbital parameters and characteristic frequencies, establishing a theoretical framework for observational tests of disformal BH spacetimes. Also, these results show the effects of modified gravity on relativistic particle motion and offer guidance for designing observational strategies capable of constraining deviations from general relativity in the strong-field regime.