Left: stellar surface-density map (σ (stars/arcmin²)) obtained for the region of 30 arcmin around the clusters. The comparison field-stars area is indicated by dashed lines, while the full line indicates the cluster area. Centre: a zoom of the σ map indicating by crosses the position of objects with membership probability P > 70%. Right: the distribution of the stellar density as a function of radius. The best fitting of observed radial density profile, indicated by the full line, was obtained by using the model from King (1962). A dashed line indicates the background density (σ_bg).