Left: azimuthally-averaged surface brightness profiles in the WFC3/F160W and 110W bands. The PSF is shown in green. The red band indicates radii near the critical line, where the Ruby might contribute and where an excess is seen compared to the Sersic profile (red line) fitted to the inner 0.5′′ in the F160W band. The fit to the F110W band was simply scaled to the central surface brightness. These regions are also seen in the residual images (right) after subtracting the model.