Left panel: luminosity at a rest-frame frequency of 1.4 GHz for different redshifts computed using the fiducial value of 1 μJy for (observer frame) 3 GHz flux densities, right panel: correction of 1.4 GHz radio luminosity, C_L1.4 GHz computed using the spectral index of α = 0.7 as reference. Solid lines are corrections based on either a broken power-law (red line), derived in Sect. 5 for our HSFG sample, and an SED (black line) of normal star-forming galaxies based on a 0.97 nonthermal spectral index and a 10% thermal fraction (Tabatabaei et al. 2017). The green line shows the SED of NSFGs based on a simple power law (α = 0.79 Tabatabaei et al. 2017).