We propose to investigate fundamental questions concerning the formation and evolution of galaxies, by adopting the Galactic Archaeology approach. As the Sun is treated as a special star for the incredible amount of detail with which it can be studied, in the same way the Milky Way (MW) and Local Group (LG) galaxies are considered the Rosetta Stone for the study of galaxy formation and evolution. This is due to the unique possibility of resolving them into individual stars, for which positions, motions, elemental abundances and ages can be derived. We can then acquire an exquisite, multi-dimensional view of their structure and chemodynamic properties, and how these have varied with time. We can also measure their gravitational potential and obtain insights into the mysterious dark matter component. Our project revolves around two key areas: the determination of the build-up history of the MW disk and halo, and the determination of the dark matter content and distribution in LG dwarf galaxies, which are key test beds of dark matter theories his is a unique and crucial moment for addressing these topics. The availability of accurate Gaia photometry and parallaxes for millions of MW stars, within several Kpc from the Sun, opens the door, for the first time, to derive star formation histories for representative volumes in our Galaxy, using the same techniques that have proven successful in the study of LG galaxies and on which we are recognized leaders. The unbiased age distributions that we will obtain are the key missing ingredient required to interpret the incredible wealth of existing observations in the context of galaxy models. Combined with kinematic and chemical information for millions of stars from large ground based spectroscopic surveys such as GALAH, LAMOST, SDSS WEAVE and 4MOST, we will obtain an unprecedented view of our Galaxy. In parallel, we aim to pave the way for the next generation dark matter determinations of LG dwarf galaxies. The individual propermotions of Gaia DR4 will finally provide individual tangential motions in classical MW dwarf galaxies, giving a huge leverage for dark matter determinations. We aim at preparing the tools and observational framework needed to exploit at best those data when the time comes.
In parallel, we will be harvesting the results from an innovative method we developed, which we can determine both the dark matter halo slope and shape in systems with both stellar and HI kinematics, with greatly reduced uncertainties in the determination of the dark matter slope. We have a recognized role at the international level in the topics proposed. This is demonstrated, e.g. by the high impact results from the timely exploitation of Gaia DR2 data (e.g. Fritz, Battaglia+2018, 26 cit; Gallart, Ruiz-Lara+2019, 51 cit), the invitations to deliver review talks at international conferences, the active participation in leading roles to the actual design and strategy for crucial spectroscopic surveys such as WEAVE Galactic Archaeology.
The results of our research are guaranteed to have an international impact, contributing to the scientific excellence of Spain and Europe. . We are aware that the goals are very ambitious, but we believe they will be feasible if we are awarded with the requested personnel.