The Gaia-ESO Survey: {\alpha}-abundances of metal-poor stars
  We performed a detailed study of the ratio of low-{\alpha} to high-{\alpha}
stars in the Galactic halo as observed by the Gaia-ESO Survey. Using a sample
of 381 metal-poor stars from the second internal data release, we found that
the value of this ratio did not show evidence of systematic trends as a
function of metallicity, surface gravity, Galactic latitude, Galactic
longitude, height above the Galactic plane, and Galactocentric radius. We
conclude that the {\alpha}-poor/{\alpha}-rich value of 0.28 $\pm$ 0.08 suggests
that in the inner halo, the larger portion of stars were formed in a high star
formation rate environment, and about 15% of the metal-poor stars originated
from much lower star formation rate environments.
