Parameter constraints combining two-point correlation function and luminosity function likelihoods. Top panel: likelihood function of (Ω_m0, σ₈) from the cluster two-point correlation function (blue), X-ray luminosity function (red), and joint distribution (green). The light and dark contours are the 68% and 95% confidence regions, respectively, and the dashed red lines show the best-fit values for the joint likelihood. Bottom panel: marginalized posterior distributions for Ω_m0 and σ₈ obtained from the joint likelihood in the top panel. The dashed black lines show the 16%, 50%, and 84% quantiles.