Merger rate density of Pop. III BBHs in star clusters. We assume that all of our clusters are disrupted at z_min = 10. We show both log1 (solid lines) and log1che (dashed lines). Isolated and original BBHs are shown in blue and purple, respectively. DynA and DynB BBHs are shown in red and orange, respectively. In the upper (lower) plot, we show the BBH merger rate density in HM (LM) clusters.