Title: Overview of Astrometric VLBI and Celestial Reference Frames
Author: Prof Patrick Charlot
Astrophysique de Bordeaux
Université de Bordeaux
Overview of Astrometric VLBI & Celestial Reference Frames.
More about the author:
Patrick Charlot has worked in the field of geodetic, astrometric and astrophysical VLBI for more than 30 years, originally at Paris Observatory (where he obtained a Ph. D. in 1989) and since 1998 at the University of Bordeaux in the southwest of France. He also stayed as a postdoc fellow at the Jet Propulsion Laboratory (USA) in 1989-1990.
Patrick pioneered studies of radio source structure from geodetic and astrometric VLBI data, including the effect of such structures on the VLBI observables and the celestial reference frame. Following up on his early work, he introduced the now widely-used structure index, an indicator of source quality, and pushed imaging of the reference frame sources. This led to the Bordeaux VLBI Image Database, which now incorporates more than 6000 images from extragalactic radio sources. Additional contributions are concerned with studies of the Earth’s precession and nutation, the estimation of the link between the dynamical and extragalactic frames, and astrophysics of active galactic nuclei, in particular from VLBI observations.
Patrick currently chairs the ICRF3 Working Group, in charge of building the next generation celestial reference frame. He has also long been connected to European VLBI, e.g. as chair of the European VLBI Network Program Committee from 2003 to 2008 or at present through the project JUMPING JIVE. Patrick is a member of the JIVE council, representing France, and a member of the IVS Directing Board, representing the International Astronomical Union. His interest also extends to the Gaia space mission for linking the radio and optical frames and understanding the underlying source physics. He is a member of the Data Processing and Analysis Consortium for Gaia. Patrick was Director of the Laboratoire d’Astrophysique de Bordeaux (formerly Bordeaux Observatory) from 2008 to 2015.