Symposium S15  28-29 June 2021

Gaia: The (TWO) Billion Star Galaxy Census: The Science of EDR3 and the promise of DR3


  • 20210115 Session Information updated.

Aims and scope

The updated ESA Gaia Billion Star Census of the Milky Way, was released 3 December 2020 as the Gaia Early Data Release 3 (Gaia EDR3). This release updates and extends Gaia DR2, and contains full five parameter astrometry for ~1.5 billion sources, along with a wealth of associated data (such as magnitudes, colours, mean radial velocities for brighter objects - see for details). This marks a further major milestone in the Gaia mission, following on from the Gaia Data Release 2 (Gaia DR2) in April 2018. Gaia is revolutionising 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 and related communities (and especially early stage researchers) to present and discuss their science highlights resulting from Gaia EDR3 and in anticipation of the Gaia DR3. It will allow the Gaia project to update the science community with the latest scientific and technical performance of Gaia, looking ahead to the release of Gaia DR3.

In addition there will be a lunchtime session, providing demonstrations of the advanced ways in which the Gaia data can be accessed through the Gaia Data Archive.

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, in the form of the MW-Gaia COST Action ( is currently financially supporting networking activities across Europe.

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 14th 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) and Leiden (S10)).


  • Gaia EDR3: Highlight Science
  • Gaia / GREAT/MW-Gaia / Gaia Unlimited Status
  • Gaia EDR3: Highlight Science (The Milky Way as a Galaxy)
  • Gaia EDR3: Highlight Science (The Birth, Life and Death of Stars)
  • Gaia EDR3: 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 also an opportunity for poster presenters to deliver a 'lightening' talk of their (e-)poster.

Invited speakers

The speakers and programme will be available at the meeting website - see
Session 1 will include a headline talk from Alis Deason (University of Durham, UK) 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), and Timo Prusti (ESTEC, ESA). The organising committee consists of the members of the Gaia Science Team and the DPAC Executive: Carine Babusiaux (Grenoble, FR), Michael Biermann (Heidelberg, DE), Anthony Brown (Leiden, NL), Orlagh Creevey (Nice, FR), Christine Ducorant (Bordeaux, FR), Dafydd Wyn Evans (Cambridge, UK), Laurent Eyer (Geneva, CH), Alex Hutton (ESAC, ESA, ES), Carme Jordi (Barcelona, ES), Lennart Lindegren (Lund, SE), Xavier Luri (Barcelona, ES), Sergei Klioner (Dresden, DE), Francois Mignard (Nice, FR), Chantal Panem (Toulouse, FR), Dimitri Pourbaix (Brussels, BE), Timo Prusti (ESTEC, ESA, NL), Sofia Randich (INAF-Arcetri, IT), Paola Sartoretti (Paris, FR), Caroline Soubiran (Bordeaux, FR), Paolo Tanga (Nice, FR), Antonella Vallenari (Padua, IT), Nicholas Walton (Cambridge, UK)


Nicholas Walton (naw at

Updated on Sun Jan 16 17:55:47 CET 2022