"Uncovering the Ancient Milky Way"

The Milky Way's ancient, low-metallicity stars and its surrounding dwarf galaxies provide unique windows into early galaxy formation and initial episodes of element production. Recent advances in metallicity-sensitive imaging have significantly enhanced our ability to identify these stars, with high potential for new insights on Population III nucleosynthesis, early small-scale galaxy formation, and the assembly history of galaxies. I will present three results highlighting this: (1) the discovery of extended low-metallicity stellar populations around several dwarf galaxies, with a focus on the Tucana II ultra-faint dwarf galaxy, suggesting the presence of extended halos in some of these relic systems; (2) detailed chemical abundance analyses of stars in the outskirts of two of these systems, shedding light on their formation mechanisms; and (3) the detection and characterization of an [Fe/H] < -4.0 star in the Large Magellanic Cloud (LMC)—the most iron-poor star identified in an external galaxy-- plausibly providing insights on the signatures of extragalactic Population III supernovae as a unique comparison point to analogous signatures seen in the Milky Way. Finally, I will introduce a new large-scale Dark Energy Camera survey, which is employing a metallicity-sensitive narrow-band CaHK filter to image a quarter of the southern sky. This new survey will significantly push the boundaries of low-metallicity, low surface brightness studies in the Milky Way and Magellanic Clouds, with potential to scale the aforementioned results to population-level insights across a significant swath of the southern sky.