Sarah Kane

Globular clusters (GCs) are old, densely packed groups of thousands to millions of stars and have been hypothesized to be building blocks of the Milky Way's stellar halo due to their high star formation efficiency. Excitingly, early results from JWST suggest that clustered star formation may also be dominant in other galaxies at high redshifts. Although the Milky Way is a perfect laboratory in which to study GCs given our ability to resolve individual stars, the clusters we observe today are likely to be only the most initially massive survivors of what was once a much larger population of Galactic GCs. I will describe how we can trace the contribution of the Milky Way's disrupted GCs to the Galaxy by finding their most unusual stars, those with such high nitrogen-to-oxygen ratios ([N/O]) that they can reliably be identified as having originated in a GC even long after escaping. The nitrogen overabundance in some GC stars is so strong that we can identify them using a neural network applied to low-resolution Gaia BP/RP spectra. I will then summarize our recent work to determine which of these anomalous GC-origin stars in the field may have been born in surviving Milky Way GCs by associating stars and clusters via their integrals of motion. Although in bulk it appears that the high-[N/O] stars originated in inner-Galaxy GCs, specific star-to-cluster tagging is complicated because integrals of motion are likely not conserved because of dynamical friction and the Galactic bar, with implications for chemodynamical tagging in the halo.