Optical images of boson stars with nonlinear electrodynamics

Based on the theoretical framework combining Einstein's nonlinear electrodynamics with minimal coupling to a free complex scalar field, this study conducts a systematic study of the observational optical characteristics and redshift effects of boson stars. In this study, the celestial sphere model and thin accretion disk serve as exclusive background illumination sources, with particular focus on how variations in the initial scalar field configuration, magnetic field strength, and free parameters influence the observational signatures of boson stars. By numerically solving the coupled system of equations governing the scalar field and gravitational field, this study obtains numerical solutions for both the scalar field configuration and metric components. These solutions are subsequently processed through numerical fitting techniques to derive analytical functional representations of the metric components. The results indicate that the first derivative of the effective potential of a boson star increases with the radial coordinate r and tends to zero at infinity. By employing both the celestial sphere model and thin-disk accretion model, this study has successfully generated the optical observational images of the boson star. All simulated images exhibit a distinct bright ring structure, whose diameter, thickness, and luminosity show strong dependence on the initial scalar field configuration, magnetic field strength, and free parameters. Interestingly, the existence of photon rings is also dependent on these parameters. These findings demonstrate that black holes and boson stars can be distinguished based on their optical observational signatures.