Predicted averaged circularised surface mass density Σ(< R) (left) and mass enclosed M(< R) (right) within one effective radius R_eff = 0.5″ (3.5 kpc) of the source galaxy, with the corresponding CI (shaded regions). Both the convergence and the enclosed mass of the source of the MFL model (see Sect. 3.2.3) are underestimated in the outskirts, as compared to the input and the LD model. This is also shown in the v_rms value, which is slightly underestimated, as shown in Fig. 9.