Coffee talks
Monday 03/11/2025 @ 14:30, Sala riunioni quarto piano e on line (meet.google.com/sue-bwvk-axf)
Sanghyun Kim (KASI, Korea Astronomy and Space Science Institute, Daejeon, South Korea), "Probing the origin of high-energy emission in blazar jets using high-resolution VLBI"
The dawn of a new era in high-energy astrophysics began with two significant advancements: the upcoming operations of the Cherenkov Telescope Array Observatory (CTAO) and the active detection of high-energy neutrinos by the IceCube observatory. Blazars, active galactic nuclei with relativistic jets pointed toward Earth, dominate the extragalactic gamma-ray sky and have emerged as promising candidates for high-energy neutrino sources. A key challenge remains: understanding the physical processes of particle acceleration that produce high-energy emission. Very long baseline interferometry (VLBI) offers the unique capability to probe and resolve parsec-scale regions in blazar jets, clarifying the connection between radio and high-energy emission. In this talk, I will present results from multiwavelength variability and VLBI studies of high-energy-emitting blazars. This includes analyses of spectral properties and multiwavelength correlations with respect to high-energy light curves, as well as VLBI jet kinematics linked to gamma-ray flares. Finally, I will introduce our plan to perform high-resolution, multi-frequency polarimetric VLBI observations to achieve crucial multiwavelength synergy, which will ultimately deepen our understanding of the high-energy universe and the mechanisms driving particle acceleration.