Description
The field of Galactic archaeology has been transformed over the last decade thanks to the Gaia revolution. In particular, Gaia provides the full 6D phase-space information for stars in the local halo, allowing us to characterise their orbits and integrals of motion (IoM), such as energy and angular momentum. During an accretion event, stars from a single merger are deposited onto similar orbits, resulting in overdensities in IoM space that remain roughly conserved over time. By applying clustering techniques to Gaia data, we have been able to identify and characterise several accreted substructures in the local stellar halo. Thanks to Gaia, we now know that the local halo is dominated by the debris from a single massive merger named Gaia Sausage Enceladus. I will present our updated view of the Milky Way's accretion history emerging from Gaia data and discuss how the upcoming Gaia NIR mission will further advance our ability to reconstruct the Milky Way’s assembly history.
