Contours of the ATCA tapered image centred at 1.867 GHz are overlaid on the ATCA wide-band tapered (left) and full-resolution maps (right). Dashed contours correspond to the islands of significant emission detected by PyBDSM on the Block 3 tapered map (cyan contours in Fig. A.1). The continuous curves trace instead “classical” 3, 3 , 6σ contours (i.e. with the 51.1 μJy/beam rms value of the map estimated by hand on the Block 3 tapered map at ~30 arcsec resolution; see Table 2).