The Milky Way, Coming into Focus: Precision Astrometry Probes its Evolution, and its Dark Matter

Abstract

The growing trove of precision astrometric observations from the Gaia space telescope and other surveys is revealing the structure and dynamics of the Milky Way in ever more exquisite detail. We summarize the current status of our understanding of the structure and the characteristics of the Milky Way, and we review the emerging picture: the Milky Way is evolving through interactions with the massive satellite galaxies that stud its volume, with evidence pointing to a cataclysmic past. It is also woven with stellar streams, and observations of streams, satellites, and field stars offer new constraints on its dark matter, both on its spatial distribution and its fundamental nature. The recent years have brought much focus to the study of dwarf galaxies found within our Galaxy's halo and their internal matter distributions. In this review, we focus on the predictions of the cold dark matter paradigm at small mass scales through precision astrometric measurements, and we summarize the modern consensus on the extent to which small-scale probes are consistent with this paradigm. We note the discovery prospects of these studies, and also how they intertwine with probes of the dynamics and evolution of the Milky Way in various and distinct ways.

87 pages, LaTeX, 25 figures; to be published by: Progress in Particle and Nuclear Physics, in 2021; references, corrections added in proof

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Cited by in corpus (11)

• The Return of the Templates: Revisiting the Galactic Center Excess with Multi-Messenger Observations
• Neutron Stars with Baryon Number Violation, Probing Dark Sectors
• Forecasts for Galaxy Formation and Dark Matter Constraints from Dwarf Galaxy Surveys
• Milky Way-est: Cosmological Zoom-in Simulations with Large Magellanic Cloud and Gaia-Sausage-Enceladus Analogs
• Astrometric Gravitational-Wave Detection via Stellar Interferometry
• Directional Detection of Dark Matter Using Solid-State Quantum Sensing
• Probing Dark Sectors with Neutron Stars
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• A Wave-Corrected Assessment of the Local Midplane
• Using two point correlation functions to understand the assembly histories of Milky Way-like galaxies
• Newtonian Gravity and Galaxy Rotation Curves: An Axisymmetric Green's Function Perspective