This project aims at understanding the formation of the Milky Way from observations of the stellar populations which bear the imprint of early Galactic evolution in their chemical abundances, kinematics, and spatial distribution. We plan to study the inner regions of the Milky Way, where most of the stellar mass resides, in order to understand the physical process of formation of the bulge, either by early accretions, by gravitational collapse or by disc instability (bar or pseudo-bulge).
Using our data sets, we will study the role of radial mixing in the evolution of the disc, the links and interaction between the bulge, the inner disc and the thick disc populations. We shall analyse about 30 fields distributed in the central regions and around, several millions of stars with photometry and astrometry (proper motions), several thousands stars with spectroscopy (elemental abundances and radial velocities), complemented by observations in the visible and near-infrared from public data.
We shall then be able to identify the characteristics which allow to distinguish different scenarios of formation of these populations (determination of the epoch of formation, history of star formation, identify tracers of merging events in different populations, role of the dynamical interaction between those populations, role of migrations).
In parallel we shall integrate the results obtained from our analysis in a population synthesis model which will permit to ensure the consistency of parameters obtained with an overall scheme. This will also test the robustness of the results against possible bias and if necessary to find the method for correcting these bias.
Finally, the model will be able to provide simulations in the form of mock catalogues, usable for the preparation of future projects, and in the framework of the Virtual Observatory. Our experience in large data sets analysis and model developement will be valuable in future analysis of large scale surveys in particular Gaia.