Research Interests
My research focuses on VLBI and multiwavelength observations of compact radio sources (e.g., the black hole candidate in the Galactic center Sagittarius A*) and extragalactic jets. With high-resolution VLBI monitoring I am studying the structure at scales much less than a parsec. Related broadband studies (e.g. with XMM-Newton, Suzaku, Chandra, HST, and Fermi/LAT) allow me to investigate the spectral energy distribution and variability of these sources to gain crucial information on the underlying physical mechanisms. I am interested in how jets evolve, why some are high-energy emitters, what are the emission mechanism (are they neutrino sources?), what happens when they interact with the ambient medium etc. ... PhD thesis: PDF Diploma thesis: PDF
BlackHoleCam & EHT
My current projects are conducted in the framework of BlackHoleCam and the Event Horizon Telescope. We have the aim to make the very first image of a black hole.
Centaurus A
VLBI observations with TANAMI allow us to image the closest radio galaxy in unprecedented detail. We can study the jet-counterjet system at sub-parsec scales revealing multiple possible gamma-ray emission zones as well as complex kinematics.
PMN J1603-4904
This gamma-ray loud extragalactic jet is very peculiar: it shows unusual broadband spectral properties for a blazar and VLBI observations reveal a compact symmetric structure on milliarcsecond scales. We discuss an alternative classification as a young radio galaxy.