Dynamical BBH merger rate in the simulated galaxies m11e, m11h, m11d, and m12i (left to right). In each subplot, the BBH merger rate is shown as a solid coloured line (number of mergers per unit time). Dotted lines represent the BBH merger rates of massive BBHs (M_BH1 > 50 M_⊙). The filled areas correspond to the formation rate of massive clusters. They indicate the total mass of massive clusters formed, divided by 10⁵ M_⊙, per unit time. The solid black line shows the SFR, divided by 10⁵ M_⊙, for comparison.