Determining the three-dimensional distribution of interstellar gas and dust in the Central Molecular Zone of the Milky Way is an open problem of fundamental importance to several astrophysical communities, including the community studying the process of star formation. The Galactic centre is the most active star-forming region in the entire Galaxy and is considered a unique laboratory for studying the birth of new stars in extreme environments. Since stars are born from the gravitational collapse of the interstellar medium, determining the 3D distribution of the latter is indispensable if we are to understand where, how and when new stars form.
In the 3D-Gal project, we will use an innovative new methodology combined with recent observational data obtained from state-of-the-art telescopes, such as the HAWK-I (High Wide field K-band Imager) instrument located on the ESO (European Southern Observatory) VLT (Very Large Telescope), to determine the three-dimensional distribution of the interstellar medium in the Galactic centre. The methodology exploits the fact that clouds of interstellar medium obscure the stars behind them but not those in front of them, and that stars at different distances from the Galactic centre move at different speeds that have recently been measured by the GALACTICNUCLEUS collaboration. Using this information and a maximisation algorithm, we will be able to determine a three-dimensional probability distribution for the position of the clouds. The project will enable us to obtain a detailed three-dimensional map of the Galactic centre for the first time, which will be made freely available to the astrophysical community.
The 3D-Gal project complements the ERC ‘GalFlow’ project and significantly strengthens it both in terms of science and of scientific dissemination. In parallel to the purely scientific activities, we plan to engage in popularisation and educational activities, in particular through the new observatory/planetarium in Sormano.