Speaker
Description
Geodetic VLBI is a powerful technique that has been used for 40 years to monitor the Earth’s rotation and realize the terrestrial and celestial reference frames with an unprecedented precision (< 0.1 mas). Recently, it has permitted the construction of the third realization of the International Celestial Reference Frame (ICRF3) which is currently the most precise celestial reference frame. Recently also, Gaia provided an independent astrometric solution whose precision is, for the first time, comparable to VLBI, opening the way to comparisons of positions at various wavelengths. In this talk, I will show the signature of relativistic jets - and more generally of the source structure - in geodetic VLBI observations, and the systematics and offsets between VLBI and Gaia positions.
