Understanding the Physics of μas Structures in Active Galactic Nuclei

Abstract: Active Galactic Nuclei (AGN) are some of the most luminous objects in the universe, powered by accretion onto supermassive black holes (SMBHs). Recent advances in very long baseline interferometry (VLBI) have revealed compact structures with sizes of just a few microarcseconds (μas), providing a unique window into the innermost regions of these systems. In this talk, we will explore the physical processes associated with these fine structures in AGN, focusing on the role of magnetic fields and the plasma environment around SMBHs, and their observational signatures in multiwavelength and multi messenger regime. Finally, we will discuss the current understanding of the launching mechanisms of relativistic jets and the prospects for future studies using upcoming VLBI facilities such as the Event Horizon Telescope, New Generation Event Horizon Telescope, and future space VLBI missions, which promise to revolutionize our understanding of the physics of AGN and the nature of black holes.