Gaia CU9: facilitating UK exploitation of Gaia data

This work will ensure Gaia data is made available in a manner which is optimal for UK science exploitation, by supporting UK leadership roles in the delivery of the Gaia Data Archive, with involvement in the key areas of science requirements definition, documentation, and archive design. Gaia is the cornerstone ESA mission which is providing the first astrometric census of the sky. Of order two billion sources are surveyed; allowing major advances in Galactic structure and evolution, stellar evolution, solar system dynamics, exoplanetary systems, cosmology and fundamental physics. Gaia was launched in December 2013. The huge data set resulting from the third data release (13 June 2022) continues to revolutionise much of astrophysics. The fourth and fifth data releases represent the full releases from the nominal mission and extended mission phases respectively. With the full epoch data to be released in both, the full potential of Gaia will be realised. This proposal is to further support the UK contributions to the Gaia Coordination Unit 9 (CU9, Publication of the Gaia archive) in enabling the Gaia data releases, especially in: (1) the organization and supervision of the beta-testing activities; (2) coordinating the release documentation and preparing the presentation of the documentation in different formats; (3) archive enhancements in dealing with high volume, multi-dimensional data; (4) Validation of the time series photometric variability data and (5) support for further developments of the TOPCAT public-access interface software. The fourth data release, the focus of this grant period, will cover all epoch data for 60 months of observations, and contain of order 10^12 entries, in astrometry, photometry and radial velocities.