Characterization of the position and mass of the localized subhalo based on our model of lens LS. Top left: ψ_pix model, from which we assign the detected subhalo position to the minimum of the clear negative feature, in good agreement with the input subhalo position. Top right: pixelated convergence model κ_pix obtained from the ψ_pix model. We indicate the fiducial pixelated region within which we compute the subhalo mass, defined as the pixels with S/N(ψ_pix) > 3 (see also the bottom panel of Fig. 5). A smaller region corresponding to S/N(ψ_pix) > 5 is also shown, in dashed lines. Bottom: posterior distributions of the subhalo mass, as estimated from the pixelated model, and from the refined model that replaces ψ_pix with a SIS profile for the subhalo. The two pairs of posterior distributions corresponding to each pixelated region are shown in continuous (S/N(ψ_pix) > 3) or dashed lines (S/N(ψ_pix) > 5). For each pixelated region, the black dotted line indicates the mass computed from the input convergence profile of the subhalo.