Target selection. Top: zoom in equatorial coordinates on the PIGS-Sgr photometric footprint after all the cuts (gray points are the Sgr candidate members). The black cross identifies the nuclear globular cluster M54, and the contour ellipse marks its spatial extent. The FLAMES targets are colored according to their radial velocities. Bottom: proper motion space (with mean values subtracted) for the Sgr-PIGS selection and the FLAMES targets.