Radio-FIR slope q versus 1.4 GHz radio luminosity for the NVSS sources from Miller & Owen (2001). The colours represent the WHAN type (top) and radio galaxy type (bottom), cluster members are indicated by filled, background galaxies by open circles. Over-plotted plus signs indicate morphological peculiarities. The dotted vertical line represents a (statistical) luminosity threshold for AGN, the dashed horizontal line separates SF galaxies (top) from AGN (bottom). Cluster members outside the “clump” around q = 2.3, log L_1.4GHz = 22 are labelled with their catalogue numbers.