On Tuesday 10 October 2023, an intermediate version of the Gaia data will be published between DR3 (June 2022) and DR4 (end 2025). This has kept the researchers and engineers in the Gaia team in Nice busy! To explain the properties and main results of this data, five research articles will be published at the same time (see link below). For three of them, researchers from the Observatoire de la Côte d'Azur were among the main authors. They cover a wide range of subjects, from the solar system to distant quasars.

Asteroid astrometry and orbits, « Gaia Focus Product Release: Asteroid orbital solutions by Gaia » by Gaia Collaboration, P. David, F. Mignard, D. Hestroffer, P. Tanga, et al.

The FPR contains the astrometry of more than 150 thousand asteroids, the same that were present in DR3, but over 66 months instead of 34. This covers the whole nominal mission of Gaia. It is the first time that we cover such a long time span with asteroid astrometry, to the benefit of orbit improvement, Yarkovsky forces detection, prediction of stellar occultations... In the figure below, the decrease in orbit uncertainty between DR3 and the FPR : a factor 20 !

Fig 1

Spatial distribution of two diffuse interstellar bands, « Gaia Focus Product Release: Spatial distribution of two diffuse interstellar bands by Gaia Collaboration », by Gaia Collaboration, M. Schultheis et al.

With Gaia’s Focused Product Release, Gaia maps two diffuse interstellar bands, present in its RVS spectrum: one stronger and one weaker. It is the first time ever that a weak diffuse interstellar band is mapped with this detail, and… all-sky! Knowing both the strong and weak diffuse interstellar bands helps to disentangle the nature of one of the macromolecules that is out there in interstellar space, a still unsolved mystery so far.

Fig 2


Sources around strongly lensed quasars, « Gaia Focused Product Release: A catalogue of sources around quasars to search for strongly lensed quasars » by Gaia Collaboration, A. Krone-Martins, D. Ducourant, L. Galluccio et al.

Some of the objects seen by Gaia are distant of lensed quasars extremely bright galactic cores powered by black holes, whose image is deformed and duplicated several times by a galaxy in between. The FPR presents 381 solid candidates for lensed quasars: an unprecedented amount released all at once. This article will appear shortly after the release.

Fig 3

Other two articles concern astrometry and photometry of sources around the omega Centauri region, and radial velocity epoch data from long period variables.

All the details, documentation and links to access the articles on the data

Team Gaia at Lagrange laboratory (Observatoire de la Côte d'Azur, Université Côte d'Azur, CNRS) : P. Alonso-Palicio, L. Bigot, B. Carry, A. Chiavassa, O. Chreevey, P. de Laverny, M. Delbo, M. Galinier, L. Galluccio, G. Kordopatis, F. Mignard, C. Navarrete, C. Ordenovic, A. Recio-Blanco, M. Schultheis, E. Slezak, I. Slezak, F. Spoto (MPC, associé), F. Thevenin. Coordinateur : P. Tanga ; soutien administratif : S. Goletto.