Jong-Seo Kim

Bayesian calibration and imaging in radio interferometry

Scientific Advisor: Andrei P. Lobanov

Collaborators: Jakob Roth, Hendrik Mueller, Aleksei Nikonov, Torsten Ensslin,
Michael Janssen, Philipp Arras, Jongho Park, Jack Livingston, Jakob
Knollmueller, Ru-Sen Lu, Maciek Wielgus, Anton Zensus

PhD examination:  17. October 2025

My PhD project focuses on Bayesian calibration and imaging in radio
interferometry. Traditional methods, such as AIPS, CASA, and DIFMAP, treat
calibration and imaging separately, even though both rely on shared prior
knowledge about the source and instrument. The Bayesian approach developed in
this work, implemented in the Bayesian imaging resolve software, overcomes
this limitation by jointly inferring calibration and image parameters,
naturally accounting for calibration uncertainties in the final
reconstruction. Using variational inference to mitigate computational costs,
this method achieves high-fidelity and super-resolved images while providing
uncertainty estimates for calibration and imaging results. The framework is
extended to include polarimetric calibration, enabling robust full-Stokes
imaging. The approach is validated on observations of active galactic nuclei
(AGNs), key targets for studying black hole accretion and jet formation.
Applications include: galaxy M87 at 43 and 86 GHz (VLBA, GMVA+ALMA),
revealing the black hole shadow and jet with improved resolution and
quantified uncertainties in ring parameters, Quasar 3C273 (VLBA, 15 GHz) and
blazar OJ287 (GMVA+ALMA, 86 GHz), producing reliable polarimetric images and
instrumental calibration (gains, D-terms), and radio galaxy Hydra A (VLA, 2.5
GHz), demonstrating full Bayesian calibration and imaging using resolve.
Altogether, this dissertation demonstrates that Bayesian calibration and
imaging approach for full polarimetric radio interferometric data can
reconstruct reliable calibration solutions and images with high resolution
and provide better observational constraints with uncertainties to understand
the inner structure of AGNs and their jet formation.


About me:
I was born in Incheon, South Korea. I obtained my Bachelor’s degree in
Physics from Chung-Ang University in Seoul, followed by a Master’s degree
from Ludwig Maximilian University of Munich. In May 2022, I joined the VLBI
group at the MPIfR as a PhD student.