Kernel density estimate (KDE) smoothed distribution (left), proper motion distribution (middle), and CMD (right) of Gaia DR2 stars toward the NGC 6522 field. Leftmost panel: position of the newly detected member cluster candidates (red unfilled circles), the blue unfilled circle represents the star previously reported in Schiavon et al. (2017a), the green unfilled stars show the position of the field stars contained within the green shadow region as illustrated in Fig. 1, the black dots represent the Gaia DR2 stars inside the tidal radius of the cluster and whose proper motions match with the nominal proper motion of NGC 6522 within 3σ_μ, and the black dotted circle marks the size of the tidal radius of the cluster. The middle plot shows (μ_α,μ_δ) distribution and the black dotted lines show the nominal proper motion of NGC 6522. The rightmost plot shows the Gaia DR2 CMD of each star.