Star formation rate (blue line) and accretion rate (red line) versus redshift. The calculation of both rates is based on the modelling described in Sect. 5.2.2, matching the measured 1.4 GHz flux density of 15 mJy and providing the lowest deviation to all available flux density upper limits. The red shaded area represents the uncertainty in the determination of the BH accretion rate, based on varied numbers for the efficiency factor ϵ and the conversion factor κ. We note that the SFR is meant to be an upper limit since the SB contribution is only constrained by upper limits.