The Early Assembly History of the Milky Way with Extremely Metal-Poor ([Fe/H] < -3.0) Stars

Extremely metal-poor (EMP; [Fe/H] < -3.0) stars are thought to be genuine second-generation of stars because they were born from relatively pristine gas chemically enriched by one or two supernovae. So, the EMP stars presumably originated from outside the Milky Way (MW) are important tracers for the early chemical evolution and assembly history of the MW. In this study, we present the preliminary results on the early assembly history of the MW inferred by associating the dynamical properties of our EMP stars with those of known substructures in the MW. We also explore the star formation history of the progenitor galaxies of our EMP stars by investigating the elemental abundances of the EMP stars associated with the substructure.