Stellar mass versus redshift distribution of the HIERO sample. The y-axis is on a logarithmic scale. The vertical dotted red line corresponds to z = 3.5, above which we do not trust the solutions found by the fit. These high-z sources are displayed as red dots. The grey-shaded area represents the region forbidden by the ΛCDM model. The black lines show the limit for different values of ϵ. The median error for both the quantities is reported in the top-right corner of the plot. Left panel: Results from the CIGALE run described in Sect. 3.3. Right panel: Results from the low-z run for the high-z objects, which are still displayed as red dots.