Hyeon-Woo Jeong, Sang-Sung Lee, Whee Yeon Cheong, Jae-Young Kim, Jee Won Lee, Sincheol Kang, Sang-Hyun Kim, B. Rani, Jongho Park, and Mark. A. Gurwell

REBECCA LIN, MARTEN H. VAN KERKWIJK, FRANZ KIRSTEN, UE-LI PEN, AND ADAM T. DELLER

Methanol masers at 6.7 GHz have been frequently targeted by VLBI users for their bright emission and multiple uses in radio astronomy. In addition to their uses in trigonometric annual parallax measurements, it is their reliable and exclusive association with intermediate- and high-mass protostars which make them a favourite maser transition among star formation astronomers investigating the higher mass regimes. VLBI images of the 6.7 GHz methanol maser often show rings of up to 100s of AU around protostars, or arcs of maser clouds, or seemingly random distributions.

The Opticon RadioNet Pilot (ORP) is one of the European Commission's "pilot" programs under the EC H2020, launched in March 2021. This four-year project brings together 37 institutions to support and develop seamless access to radio and optical facilities.

by Gabriele Giovannini

VLBI astrometric observations of radio stars can validate the quality of Gaia Celestial Reference Frame (GCRF) and help to improve the accuracy and robustness of the link between the In

by Hendrik Müller