Quasars and AGNs, which play a fundamental role in the evolution of their host galaxies, are also used to build fundamental celestial reference systems (i.e., the ICRF) because of their extreme distances and therefore negligible proper motions. With the advent of the Gaia astrometric mission, however, visual-wavelength astrometry has entered the micro-arcsecond domain, in which significant positional offsets have been found with the radio positions of quasars. These offsets are likely physical in nature, owing to processes of direct interest to the AGN community more broadly, such as radio jet production, outflows, dual/binary AGNs, lensing, circumnuclear star formation, etc.

This conference will bring together AGN and CRF researchers to discuss these issues. The chosen venue is the Institut d’astrophysique de Paris, next to Observatoire de Paris, both institutions with a long and rich history of astrophysical research across a broad range of fields, including those pertaining to navigation,the celestial reference frame (CRF), quasar research and galaxy evolution. The date of this conference, 15-19 June 2020, is optimal as it lies between Gaia DR2, the 3rd realization of the ICRF, and Gaia DR3. During this period, the international reference frame community will be developing a road map for the next realization of the ICRF, including integration of high accuracy, visible AGN data from Gaia with the radio VLBI data that currently composes the ICRF3.

Scientific Organizing Committee
Bryan Dorland
Patrick Charlot
Eilat Glikman
Luis Ho
Megan Johnson
Claudio Ricci
Brigitte Rocca
Dave Rosario
Henrique Schmitt
Nathan Secrest
Jean Souchay
Daniel Wang

Local Organizing Committee
Christophe Barache
Pascale Baudoin
Olivier Becker
Brigitte Rocca-Volmerange
Nathan Secrest
Jean Souchay
Francois Taris