BHAR (top) and BHAR per unit SFR (bottom) as a function of stellar mass for quiescent galaxies (greyscale points) in COSMOS. Different symbols mark different redshift bins. Main-sequence galaxies in the same redshift range as studied in this work are added in the bottom panel as cyan stars. Error bars on the average BHAR reflect the dispersion of the weighted mean on the rest frame L(2–10 keV) of the sample. The average SFR_[OII] was converted into a Chabrier IMF. Adapted from Carraro et al. (2020).