Mass hyperparameter posteriors of the peak components in the COMPACTNESS PEAKS model. Left panel: the lower mass (BH_L) peak where μ_BHL is the mean of the peak, σ_BHL is the width of the peak and m_min^BH_L and m_max^BH_L are the minimum and maximum mass of the peak. Right panel: the upper mass (BH_L) peak where μ_BHH is the mean of the peak, σ_BHH is the width of the peak and m_min^BH_H and m_max^BH_H are the minimum and maximum mass of the peak. The credible intervals on the 2D posterior distributions are at 1σ, 2σ and 3σ, using increasingly light shading. The intervals on the 1D posterior distributions are at 1σ.