Abstract

Contributed Talk - Splinter RadioSky

Tuesday, 13 September 2022, 15:21   (SFG 1030 / virtual RadioSky)

TeV detected AGN jets in the TANAMI program

Petra Benke (1,2), Eduardo Ros (1), Matthias Kadler (2), Roopesh Ojha (3), Philip G. Edwards (4), Florian Rösch (2) on behalf of the TANAMI team
(1) Max-Planck-Institut für Radioastronomie; (2) Institut für Theoretische Physik und Astrophysik, Universität Würzburg; (3) NASA HQ; (4) CSIRO Space and Astronomy

The Doppler crisis in high-peaked BL Lac objects and the localization of the blazar zone in the case of TeV-detected quasars are open questions that puzzled radio astronomers in the past decades. There are some suggestions to resolve these problems, e.g. a spine-sheath structure in the jet that may be detectable with VLBI, but a clear answer has evaded us so far. Larger samples of sources and high-quality VLBI data can help us to make progress in solving these puzzles. Since most previous studies only involved northern sources, we aim to improve statistics and sky coverage by adding sources that can only be observed with southern-hemisphere telescopes. TANAMI is currently the sole VLBI monitoring program targeting southern sources, providing the only tool to probe their intrinsic jet properties and to track the morphological changes in the innermost region of these AGN. Quasi-simultaneous multiwavelength campaigns are also essential to our study. With data from the Fermi/LAT and HESS, the link between the radio and gamma-ray variability is continuously being investigated. Upcoming arrays, such as the Square Kilometer Array (SKA) and Cherenkov Telescope Array (CTA) will enable us to extend our studies to lower VLBI frequencies and higher energies in the gamma-ray domain, respectively.