Symposium S4  1-2 July 2024

Gaia: The (TWO) Billion Star Galaxy Census: from the Solar System to our Milky Way and beyond


  • 20240125 Session Information updated.

Aims and scope

The updated ESA Gaia Billion Star Census of the Milky Way, was released in June 2022 as Gaia Data Release 3 (Gaia DR3). This release updated and extended Gaia EDR3, and contains the full five parameter astrometry for ~1.5 billion sources, along with low and medium resolution spectra and a wealth of associated data (such as mean radial velocities for brighter objects ? See for details. 10 Oct 2023 saw the release of the next milestone, the Gaia Focused Product Release (Gaia FPR) ( with a set of five high value data products, spanning solar system objects to gravitational lenses.

Gaia EDR3, DR3 and the FPR mark the most recent major milestones in the Gaia mission. Gaia continues to revolutionise our understanding of the formation history of the Milky Way, and is having a significant impact on many other areas of astronomy ranging from solar system science to quasars.

The key goals of this symposium will be for the Gaia/GREAT(*1) and related communities (and especially early stage researchers) to present and discuss their science highlights resulting from Gaia EDR3 and Gaia DR3. It will allow the Gaia project to update the science community with the latest scientific and technical performance of Gaia, review the most recent Gaia DR3 enabled science, and provide an look ahead to the future release of Gaia DR4 (the full release of the 5 year Gaia nominal mission), which will be released not before the end of 2025.

GREAT plenary meetings have run since 2009, allowing members of the GREAT and wider community to participate in a dynamic fashion. They are structured around Gaia updates, presentations from related organisations (e.g. ESO), reports from new initiatives, and new science results from the network activities.

This will be the 17th GREAT plenary (which since 2012 have been organised within the high impact EAS EWASS - see the links to online materials at for the Gaia/ GREAT symposia held at the EWASS's in Rome (S5), Turku (S11, SM5), Geneva (S3), La Laguna (S9), Athens (S1), Prague (S2), Liverpool (S2), Lyon (SS28), Leiden-virtual (S10), Leiden-virtual (S15), Valencia (S12) and Krakow (S3 - talks online at

The meetings are always significantly oversubscribed in terms of paper abstract submissions, and well attended. At recent EAS meetings they have typically been amongst the larger science symposia, with over 200 participants at the 2023 Krakow meeting.

In view of Gaia DR3 and the wealth of new science being published based on this release, we propose a FULL science symposium programme. The symposium will provide an opportunity to update the community as to the science return of the new data release. In addition the meeting will allow first science from the new 2023 Gaia Focused Product Release (FPR) that will have been released to the community on 10 Oct 2023 (See details at ).

The symposium will include space for updates on initiatives aimed at optimising or leveraging the data from Gaia, together with presentations on the science topics where Gaia will have the highest impact.

In addition we will organise a lunchtime hands-on session, providing demonstrations of Gaia Data Archive, and plans for future enhancements. The lunch session will also include a set of poster lightening talks together with an update on next generation astrometry mission developments in the context of the ESA Voyage 2050.

(*1) GREAT (an initiative of the ESA Gaia Project, Gaia Science Team and Data Processing and Analysis Consortium (DPAC) Executive) is a pan-European research network involving over 1000 researchers in 20+ countries with a common interest in maximising the science potential of Gaia ( GREAT, recently in the form of the MW-Gaia COST Action ( (2019-2023) and the MWGaia Doctoral Network ( (2023-2027) was/is financially supporting networking activities across Europe.


  • Gaia DR3: Highlight Science including a review of recent major science highlights in the Gaia DR3 and Gaia Focused Product releases.
  • Gaia / GREAT/MW-Gaia / Gaia Unlimited Status
  • Gaia EDR3/DR3/FPR: Highlight Science (The Milky Way as a Galaxy)
  • Gaia EDR3/DR3/FPR: Highlight Science (The Birth, Life and Death of Stars)
  • Gaia EDR3/DR3/FPR: Highlight Science (from Solar system to reference frames)
  • Gaia networking and ground based synergies with Gaia
  • Lunch session with an update on the Gaia Archive, and update on the ESA Voyage 2050 L mission concept (GaiaNIR), and also an opportunity for poster presenters to deliver a 'lightening' talk of their (e-)poster.

Invited speakers

The speakers and programme will be available on this EAS 2024 website and also on the GREAT website - see

  • Session 1 will include a headline talk from an invited speaker
  • Session 2 will include Gaia status update talks from Timo Prusti (Gaia), Anthony Brown and Antonella Vallenari (DPAC), Nic Walton (MW-Gaia)
  • All other session talks will be contributed presentations.

Scientific organisers

The co-Chairs are Nicholas Walton (Institute of Astronomy, University of Cambridge, UK), Anthony Brown (Leiden Observatory, Leiden University, NL), Timo Prusti (ESTEC, ESA) and Antonella Vallenari INAF-Padua, IT).


Nicholas Walton (naw at

Updated on Thu Jan 25 18:19:35 CET 2024