Light capture by compact objects in gravity coupled to nonlinear electrodynamics

In this work, we investigate light capture by compact objects within a framework of gravity coupled to nonlinear electrodynamics of vacuum. Employing the effective metric approach arising in the eikonal approximation, we derive analytical expressions for the photon effective potential, the photon-sphere radius, the Lyapunov exponent, the critical impact parameter, and the geometrical capture cross section of light in the presence of a magnetic dipole field. It is shown that nonlinear electrodynamic corrections perturbatively shift the photon sphere outward, reduce the Lyapunov exponent, and enlarge the geometrical capture cross section relative to their standard Schwarzschild values. The obtained results provide a theoretical basis for future studies of photon capture in more realistic models of compact objects, including the effects of rotation, spacetime multipole moments, and more complex magnetic-field configurations.