Exciting Possibilities of Multi-Messenger Windows on Cosmic Accelerators

Active Galactic Nuclei (AGN) jets are among the most extreme particle accelerators in the universe and are thought to play a key role in the origin of ultra-high-energy cosmic rays. Yet, the physical processes inside these jets, particularly those involving heavy nuclei, remain poorly understood.

In this talk, I will explore how nuclear and atomic processes in AGN jets can leave distinctive multi-messenger signatures, from neutrino production via nuclear decays to characteristic gamma-ray features from nuclear excitations. These phenomena offer a new window into the microscopic physics of nuclei under astrophysical extreme conditions, while also serving as macroscopic probes of jet composition and acceleration mechanisms.

I will also discuss how upcoming observations, including neutrino flavor studies and MeV gamma-ray missions, could provide critical tests of these ideas and shed light on the role of nuclear physics in shaping cosmic accelerators.