The probability distributions of the constants of a (upper left panel), b (upper right panel), c (lower left panel) in Eq. (5), and the probability distribution of the intrinsic scattering parameter σ_int (lower right panel). According to these panels, the best values and the 1σ errors for the coefficients are a = 1.17 ± 0.09, b =  −0.87 ± 0.09, c = 0.88 ± 0.08, σ_int = 0.43 ± 0.05, respectively.