Dongjin Kim (CSIRO Space and Astronomy)

Abstract: Active Galactic Nuclei (AGNs) are believed to play a significant role in the formation and evolution of galaxies through their energetic jet outflows. However, observational constraints are still limited when it comes to understanding how radio jets are triggered and how jet feedback operates in different types of AGNs. To gain insights into these processes, it is crucial to study both the continuum radio jet and the circumnuclear gas in AGNs. This presentation will review high-angular-resolution VLBI studies on AGN radio jets and their immediate surroundings. Specifically, I will emphasize spectroscopic studies of AGNs using molecular absorption and highlight promising scientific opportunities that can be achieved with current and future mm/sub-mm VLBI arrays. These studies provide valuable insights into the nuclear environments of AGNs, offering a better understanding of the triggering and feedback mechanisms driving radio jet outflows.