Top panel: chemical distribution, [Mg/Fe]–[Fe/H], for the 247,013 Gaia-APOGEE stars. The dashed lines represent the adopted selection of 2517 halo stars (color), separated from the thick/thin disk stars (gray). Bottom panel: same distribution as the top panel for the 1264 halo stars selected among the 190,559 Gaia-GALAH stars.