Distributions of our target stars on the [Fe/H] – RV_helio plane, together with their histograms. The symbols are the same as in Fig. 1. The magenta lines show 1, 2, and 3σ density contours levels for the model stars from the Besançon Galaxy model. Open diamonds and magenta X-symbols indicate giant stars located in the central region of cluster candidates (< 5′) within similar ranges of proper motions, magnitude, and colors as our targets from APOGEE and Besançon model, respectively. The clump of APOGEE stars at [Fe/H] ∼ −1.5 dex in the upper panel is NGC 6544, which is a nearby foreground GC (d ∼ 3.0 kpc).