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
Local Organizing Committee