Up close and personal: galaxy evolution at high resolution in the Milky Way

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Ever since the dawn of galaxy-formation studies, the Milky Way has been one of the best places in the Universe to learn about the physics of galaxy evolution. This is especially true today, when new space- and ground-based surveys are providing positions, velocities, and basic stellar parameters for a billion stars and detailed chemical abundances and ages for millions of stars. These new large data sets represent an enormous opportunity to learn about the detailed evolutionary history of the Milky Way, but analyzing the data and deducing the important elements of galaxy evolution from this presents a novel set of challenges as well. The work in this proposal will make the next leap in our understanding of the evolution of disk galaxies like the Milky Way, by analysis and modeling of the astrometric Gaia data and spectroscopic SDSS data. This proposal will focus on the following areas. Firstly, next-generation photometric and spectroscopic data analysis using machine learning: we will develop new machine-learning and in particular artificial-intelligence methods to determine precise stellar parameters, abundances, distances, and ages for the SDSS-V data set of millions of high-resolution stellar spectra, the TESS data set of lightcurves of millions of stars, and the billion-star spectrophotometric data set from Gaia. This will provide a large, high-quality data sample. Secondly, we will use this new data set to study the detailed structure, dynamics, and evolution of the currently-sparsely-sampled central bar/bulge region of the Milky Way. Finally, we will investigate the vertical structure of the Milky Way's disk near the Sun and towards the outer edge of the disk with the new data and with simulations to understand the origin of perturbations in the vertical structure that we and other groups have recently found and how these perturbations affect the recent evolution of the Milky Way. The combination of these investigations will provide new insights into the evolution of the Milky Way, from its earliest beginnings until the present day.