Constraining the Formation History of the Galactic Disk and Halo Systems through Kinematic Studies of Metal-Poor Stars

The analyses presented in this work all fall under the umbrella term “Galactic archaeology”, the sub-field of astronomy dedicated to reconstructing the assembly and chemical-evolution history of the Galaxy. The following chapters chart a journey through the Milky Way, from the disk system to the stellar halo and the outskirts of the Galaxy, identifying stellar chemo-dynamical patterns that may shed light on the complex mechanisms involved in forming these components. In particular, I use metal-poor stars, and their close associates, carbon-enhanced metal-poor (CEMP) stars, throughout my analyses as tracer populations (or stellar “fossils”) to map features of interest. In the thick-disk, I identify two unusual CEMP populations, and describe their potential implications for the history of the disk system, potentially supporting a separable metal-weak thick-disk (MWTD) component. In the halo, I compare two CEMP-based methods for verifying the inner- and outer-halo separation, and cover the recent changes to our understanding of the halo following the release of high-precision astrometry from the Gaia satellite. At the outskirts of the halo, I present evidence of an asymmetric metallicity gradient within this region, and discuss its implications for the complex accretion history of the outer-halo component.