- Professor Jean Surdej, who is responsible for the AEOS unit (Department of Astrophysics, Geophysics and Oceanography), is interested in quasars, distant galactic nuclei, which are at a very early stage of their evolution. Virtually immobile in the canopy of heaven, they will serve as reference points to calculate how stars move in relation to them in the Milky Way. “We have an American spectroscopic database containing more than 100,000 quasars”, explains Jean Surdej. “We are using them to establish a correspondence between what Gaia will observe and what is actually there. In practice, we degrade these precise spectra to Gaia’s resolution and then, based on these new data, we try to find the characteristics (cf. redshift, extinction, etc.) of the quasars observed. At this level, our work falls under the scope of a Prodex activity [Expermiment development Program]. Nevertheless, we intend to record a total of 500,000 quasars, among the brightest in the sky.”  For J. Surdej and the two members of his team (Ludovic Delchambre and Elena Fedorova), the cherry on the cake of Gaia’s observations concerns the study of the phenomenon of gravitational mirages, which belongs to his favourite area of research in astrophysics.

- As for Eric Gosset, who is a member of GAPHE (High-Energy Astrophysics Group), he is concerned with the study of massive stars: “Gaia will help us to understand these stars whose mass is higher than 15 solar masses. Rare and statistically very distant, they have a special way of evolving which is interesting to examine. There are currently ten or so whose distance is well known. Thanks to Gaia’s precision, we hope to find many others.” His interest in massive stars has led his team (Yassine Damerdji and Thierry Morel) to cooperate with ULB concerning the use of the spectroscopic channel. It helps with the modelling of binary stars by creating computer codes that will be used to process the data in the five coming years.

With Gaia, the universe has yet more surprises in store for us. The more we discover, the more we want to know and once our curiosity has been aroused, we shall want to go even further. Alongside the ESA observatory, both Jean Surdej and Eric Gosset are conscious of being at the dawn of a new era in astrophysics.

Inside Gaia's billion-pixel camera ESA’s Gaia mission will produce an unprecedented 3D map of our Galaxy by mapping, with exquisite precision, the position and motion of a billion stars. The key to this is the billion-pixel camera at the heart of its dual telescope. This animation illustrates how the camera works.