Caustics (left) and critical curves (right) for the best model with α = 1.2, where only the four SN positions are used as constraints. A simple source with just three components, nucleus (orange), halo (red) and SN (blue) is shown in the left panel (source plane). The predicted image is shown in the right panel (image plane). The yellow dots in the right panel mark the observed position of the four SN images. The predicted position for images 2 and 3 overlap with the yellow dots. Note the additional fifth image behind the center of the galaxy.