Milky Way dynamics in light of Gaia

TL;DR

The Gaia mission has revolutionized our understanding of the Milky Way's structure and dynamics, revealing detailed mappings and disequilibrium processes, but challenges remain in fully understanding the Galaxy's key properties.

Contribution

This review synthesizes recent advances in Galactic dynamics enabled by Gaia data, highlighting new insights and ongoing challenges in modeling the Milky Way.

Findings

Detailed mapping of Galactic components across the Milky Way

Identification of disequilibrium processes in the Galaxy

Advances in understanding the gravitational potential

Abstract

The Gaia mission has triggered major developments in the field of Galactic dynamics in recent years, which we discuss in this review. The structure and kinematics of all Galactic components - disc, bar/bulge and halo - are now mapped in great detail not only in the Solar neighbourhood, but across a large part of the Milky Way. The dramatic improvements in the coverage and precision of observations revealed various disequilibrium processes, such as perturbations in the Galactic disc and the deformations of the outer halo, which are partly attributed to the interaction with satellite galaxies. The knowledge of the gravitational potential at all scales has also advanced considerably, but we are still far from having a consistent view on the key properties of the Galaxy, such as the bar pattern speed or the mass profile and shape of the dark halo. The complexity and interplay of several dynamical processes makes the interpretation of observational data challenging, and it is fair to say that more theoretical effort is needed to fully reap the fruit of the Gaia revolution.