Spatial distribution of high-certainty clusters (CST>4) from Hunt & Reffert (2023). Ages are taken from Cavallo et al. (2024) as they are more accurate for old clusters (see Sect. 2 for discussion). Top left: histogram of cluster galactocentric radii divided into young (log t < 8.5, blue) and old (log t > 8.5, red) clusters and with a 200 pc bin width. Bottom left: distribution of the same young and old clusters but in terms of altitude Z and Galactocentric radius R_GC, assuming R_GC,⊙ = 8.2 kpc. Bottom right: projection of these clusters in heliocentric Galactic co-ordinates, with the Sun located at (X,Y) = (0,0). The dotted lines indicate Galactocentric radii from 10 to 18 kpc. The shaded area is the region investigated in this study (140° ≤ ℓ ≤ 240° starting 2 kpc from the Sun). In both lower panels, the cross indicates the cluster Saurer 1, visible in Gaia data but not recovered in the blind search of Hunt & Reffert (2023).