Marginalised posterior distributions of free parameters in the Bayesian fittings of VSF laws with total gas (left column), HI only (central column), and H₂ only (right column). In the first row h_SFR is constant at 100 pc, while in the second row it flares with radius (Eq. (17)). The contours of the 2D posteriors (corners) encompass the 68.3%, 86.6%, and 95.4% probability and the red squares and lines indicate the best-fit parameters. In the 1D posteriors (diagonals), the best-fit parameters are indicated by the red line and the 16th and 84th percentiles are indicated by the black dashed lines.