Spatial distribution of targets in NGC 6522: Member candidates are highlighted with red open circles. The inner plus symbol is the center of the cluster and the black dotted line marks the tidal radius of the cluster: arcmin. Field stars from the APOGEE survey located in the commissioning plate 4332, FIELD = BAADEWIN_001-04 are plotted using small gray symbols. The unfilled cyan squares, green squares, orange triangles, and the blue open circle show cluster members analyzed in Ness et al. (2014), Barbuy et al. (2014), Recio-Blanco et al. (2017), and Schiavon et al. (2017a), respectively.