POSSUM RMs used in this work and the definition of the different RM subsamples. The background shows the Planck tSZ effect y map. The dash-dotted squares represent the (6 deg)² Band 1 ASKAP fields, namely, the “core” and “south” fields, with their centers represented by red crosses. The black contour represents the y_bdry = 4.24 × 10⁻⁶ value used to define the on-target (orange triangles) and off-target (purple dots) samples. These two are inside the 1.71 × 2.42 deg² (5.8 × 8.2 Mpc²) y-map cutout used for the analysis (see Sect. 2.2). The zoomed-in region at the top left corner of the plot shows the bridge (cyan triangles) and cluster (blue triangles) subsamples, all of which belong in the on-target region. The bridge box used to define the bridge sources is also represented to ease the interpretation of the plot.