Signatures of NED on Quasi periodic Oscillations of a Magnetically Charged Black Hole

Abstract: In this work, we explore the influence of nonlinear electrodynamics (NED) on the quasi-periodic oscillations (QPOs) of a magnetic charged black hole by analyzing the motion of test particles and their epicyclic frequencies. Starting from the effective potential, angular momentum, and energy of circular orbits, we examine how the NED parameter b alters the orbital dynamics. We find that as b increases, the system transitions smoothly from the RN regime towards the Schwarzschild profile, with observable changes in the innermost stable circular orbit (ISCO) and Keplerian frequencies. We further investigate the variation in the radii of QPOs with respect to the NED parameter b by employing the RP, WD, and ER models. We also perform Markov Chain Monte Carlo (MCMC) analysis using observational QPO data from a diverse set of black hole sources spanning stellar-mass, intermediate-mass, and supermassive regimes. The MCMC results yield consistent constraints on the parameter b across all mass regimes, indicating that NED effects leave a distinguishable signature on the QPO structure of a charged black hole.