Posterior distribution of the parameters of the foreground lens object, as obtained by the lens modeling and MCMC runs (see Sect. 5 for details). The constraints are given on the following parameters: the position (ΔRA and ΔDec in arcsec), the Einstein radius (b), the ellipticity (e), and the position angle (θ_e) with the orientation measured east of north. The contours show the 0.5, 1, 1.5, and 2σ of the integrated likelihood. The mean and the ±1σ interval around the mean are displayed as histograms along the diagonal of the plot.