Περίληψη :
OJ 287 is one of the strongest supermassive black hole binary candidates and a cornerstone target for the Event Horizon Telescope (EHT), which extends horizon-scale studies beyond Sgr A* and M87* to probe jet launching, collimation, and magnetization mechanisms. In this talk, I will present microarcsecond-resolution VLBI results connecting OJ 287's innermost jet physics to this broader EHT effort. Additionally, RadioAstron imaging at 22 GHz achieves tens-of-microarcsecond resolution, revealing a continuous, ribbon-like jet with extreme compactness, evidence for strong Doppler boosting and complex, non-axisymmetric flow. Polarimetric measurements indicate ordered magnetic-field structure in the inner jet, directly constraining jet launching and collimation scenarios. Combined with multi-epoch, multi-frequency EHT/GMVA observations, these results reveal rapid structural evolution and position-angle changes consistent with helical jet rotation, providing new constraints on jet dynamics in a system potentially influenced by binary-driven orbital motion.
