Posterior probability density function of f_HD obtained after having observed fraction of high-density mergers among ten events, for varying . The dashed line shows the current constraint, obtained after the single low-density event GRB170817A. The dotted blue line shows the constraint obtained with , but ignoring the selection effect, i.e., with r(n₁) = r(n₂) = 1. Left: assuming the population’s jet kinetic energy distribution follows the short GRB luminosity function of G16. Right: same, for that of WP15.