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Very Long Baseline Interferometry at the XXXIV General Assembly and Scientific Symposium of the International Union of Radio Science (URSI)

by Francisco Colomer (Joint Institute for VLBI ERIC, the Netherlands)

Figure 1: Participants at the VLBI session at URSI GASS. Credit: Francisco Colomer.


A Session on “Very Long Baseline Interferometry” was held on 2 September 2021, co-organised by JIVE as part of the XXXIV General Assembly and Scientific Symposium of the International Union of Radio Science (URSI GASS 2021) in Rome, Italy.

The session scope was to highlight the relevance of VLBI in the fields of astrophysics, Earth and planetary sciences by bringing together experts in each field of application, providing a view of the state-of-the-art and the desired developments, to assess the central relevance of VLBI in the continuously evolving landscape of these disciplines. VLBI is a mature technique, whose applications are unique now that the need for milliarcsecond angular resolution and for extremely accurate localisation are the ultimate frontiers for some of the hottest scientific areas. For this reason, VLBI is in the heart of some of the most advanced present and future instruments and developments (EHT, ngVLA, SKA, VGOS).

A total of 15 oral presentations reviewed the VLBI contribution to the latest developments on imaging supermassive black holes and blazar jets, faint extragalactic radio sources, neutrino production in blazars, astrophysical masers, astrometry, geodesy and construction of reference frames, next generation instrumentation and calibration techniques, and space and planetary science.
The GASS of URSI are held at intervals of three years to review current research trends, present new discoveries and make plans for the future research and special projects in all areas of radio science. The URSI GASS 2020 edition was postponed due to the COVID-19 outbreak. URSI GASS 2021 was held as a hybrid event, on-site at Sapienza Faculty of Engineering, with provision for online participation and presentations. The full program is available here.
The URSI GASS J04 session on VLBI was convened by Francisco Colomer (JIVE, the Netherlands), Taehyun Jung (KASI, Republic of Korea), Chris Jacobs (Jet Propulsion Laboratory, Caltech, USA) and Tiziana Venturi (IRA-INAF, Italy).