Model predictions for the O3 detected BBH population of the SMT channel for different η_acc values according to the legend, in orange. We show the joint distributions of chirp mass M_chirp, effective inspiral spin parameter χ_eff and binary mass ratio q. Lighter colours represent larger contour levels of 68%, 95% and 99%, respectively, constructed with pygtc (Bocquet & Carter 2016). All histograms are plotted with 30 bins without any bin smoothing.