The COMBS Survey -- III. The Chemodynamical Origins of Metal-Poor Bulge
  Stars
  The characteristics of the stellar populations in the Galactic Bulge inform
and constrain the Milky Way's formation and evolution. The metal-poor
population is particularly important in light of cosmological simulations,
which predict that some of the oldest stars in the Galaxy now reside in its
center. The metal-poor bulge appears to consist of multiple stellar populations
that require dynamical analyses to disentangle. In this work, we undertake a
detailed chemodynamical study of the metal-poor stars in the inner Galaxy.
Using R$\sim$ 20,000 VLT/GIRAFFE spectra of 319 metal-poor (-2.55
dex$\leq$[Fe/H]$\leq$0.83 dex, with $\overline{\rm{[Fe/H]}}$=-0.84 dex) stars,
we perform stellar parameter analysis and report 12 elemental abundances (C,
Na, Mg, Al, Si, Ca, Sc, Ti, Cr, Mn, Zn, Ba, and Ce) with precisions of
$\approx$0.10 dex. Based on kinematic and spatial properties, we categorise the
stars into four groups, associated with the following Galactic structures: the
inner bulge, the outer bulge, the halo, and the disk. We find evidence that the
inner and outer bulge population is more chemically complex (i.e., higher
chemical dimensionality and less correlated abundances) than the halo
population. This result suggests that the older bulge population was enriched
by a larger diversity of nucleosynthetic events. We also find one inner bulge
star with a [Ca/Mg] ratio consistent with theoretical pair-instability
supernova yields and two stars that have chemistry consistent with globular
cluster stars.
