Diagonal histograms: probability density functions (PDFs) for the lens model parameters of the main lensing galaxy (D), which were obtained by marginalizing over all the other model parameters, with two dashed vertical lines indicating the 1σ limits. The other panels show the 2-dimensional contours of the PDF for each pair of model parameters, where the contours indicate the 1σ region. The meaning of the parameters, their maximum-likelihood model value and their uncertainties are presented in Table 3.