Posterior probability density in the (σ_DRW, R_BLR) parameter space marginalised over the microlensing parameters given ⟨M⟩ = 0.3 M_⊙. R_BLR is given in units of R_BLRMK11 = 1.71 × 10¹⁷ cm, indicated by the white dashed line. The contours correspond to the 1 and 2−σ confidence intervals. Marginalised probability distributions of σ_DRW and R_BLR are given in the top and right histograms respectively. In each histogram, the black line shows the 50th percentile (median value) of the distribution and the dashed lines highlight the 16th and 84th percentiles. Hence, we obtain and cm.