Photometric stellar surveys now cover a large fraction of the sky, probe to fainter magnitudes than large-scale spectroscopic surveys, and are relatively free from the target selection biases often associated with such studies. Photometric-metallicity estimates that include narrow/medium-band filters can achieve comparable accuracy and precision to existing low-resolution spectroscopic surveys such as Sloan Digital Sky Survey/SEGUE and LAMOST. Here we report on an effort to identify likely members of the Galactic disk system among the very metal-poor (VMP; [Fe/H]{<=}-2) and extremely metal-poor (EMP; [Fe/H]{150km/s). The total number of candidate VMP/EMP disklike stars is 1496, the majority of which have low orbital eccentricities, ecc<=0.4; many have ecc<=0.2. The large fractions of VMP/EMP stars associated with the Milky Way disk system strongly suggest the presence of an early-forming "primordial" disk.

Cone search capability for table J/ApJS/273/12/tablea1 (Candidate VMP/EMP stars in the combined SMSS/SAGES sample)

Cone search capability for table J/ApJS/273/12/tablea2 (1496 VMP/EMP disk-like candidate stars in the combined SMSS/SAGES sample)