Redshift and luminosity distributions of the sources. The total IR luminosity L_IR, plotted on the y-axis, is an output of the SED fitting. The small dots represent the whole sample and the filled circles the subsample of galaxies selected around within each redsfhift bin (bin 1: red; bin 2: blue, split in two subbins corresponding to z< 1 and z> 1; bin 3: green; bin 4: magenta). The adopted values of 10.84 (bin 1), 11.5 (bin 2, z< 1), 11.7 (bin 2, z> 1), 12 (bin 3), and 12.35 (bin 4). The bin size in luminosity is 0.6 dex. Detection limits at 5σ are reported as a black line.