1.4 GHz radio source counts for the supercluster area (red triangles), and the field with good rms excluding the supercluster area (black). Red dots are slightly offset from the bin centres for better visualisation. Errors are Poissonian, calculated using approximate algebraic expressions from Gehrels (1986). Radio source counts from Condon et al. (2012) are shown by the blue line. The flux densities at 1.4 GHz were calculated from the 3 GHz fluxes assuming a spectral index of − 0.7 for consistency with Condon et al. (2012).