Observed stellar mass distribution as a function of redshift for the three LoTSS Deep Fields. The background density plot shows the mass distribution of sources brighter than the 90% magnitude limit of the most sensitive reference band available in that field (4.5 μm for Boötes and K for EN1 and LH). Solid lines represent the 90% mass completeness limits, , derived empirically (Pozzetti et al. 2010) and dashed lines show the corresponding limits derived from model stellar populations. The blue completeness curves are derived based on the K or K_s magnitude limit, while red curves are derived from the widest area 4.5 μm limit (i.e. SWIRE for EN1 and LH).