The Galactic Forest

Abstract

Much like we learn about our own roots by tracing the twists and turns in our family trees, galactic archaeologists seek to understand our collective cosmic origin by studying the history of our own Galaxy, the Milky Way. In this thesis, we will present a set of star-by-star simulations of the Galaxy that have the computational tractability of simple, analytical models and allow for a direct comparison with the data. The two fundamental questions this work will address are: (1) what is the nature of star formation in our own galaxy and others like ours?, and (2) what is the origin and evolution of some of the largest structures -- such as the spiral arms, the galactic bar, and massive star-forming clouds -- in our galaxy? We utilize our star-by-star simulations to quantify the small-scale and large-scale clustering of stars using the two-point correlation function (TPCF). The TPCF allows us to assess the relative importance of star formation and the Galactic potential in shaping the positions and velocities of stars that Gaia observes today. Moreover, our simulations also predict the timescales for which stars that are born together in the same molecular cloud will stay identifiable in phase space -- both through the study of comoving pairs of stars and stellar streams of stars in our simulations. Both the physical models and statistical techniques presented in this thesis set the stage to study the nature of star formation and the Galactic potential at an unprecedented resolution and scale.