Our Galaxy in motion: Ripples, ridges and spirals in the Milky Way

Data from ESA’s Gaia mission is already revolutionizing Galactic astronomy, providing an unprecedented view of the Solar neighborhood and beyond. However, while it provides us a great opportunity to transform our understanding of the Milky Way, it has also highlighted how far from equilibrium our Galaxy is. The spiral pattern in vertical position vs. velocity is a signature of our Galaxy’s past interaction with perturbing influences such as merging dwarf galaxies, or internal substructure. We dissect and analyze these ‘phase spirals’, showing the first discovery of two armed ‘breathing spirals’ in the inner disc, and show how we can leverage high resolution galaxy models and dynamical theory to learn about the structure and history of our Galaxy.