One-dimensional profiles along the Mothra arc. The left panel shows the observed surface-brightness profiles along the arc. Image a′ is on the left, Mothra is the peak in the middle at 3″, and a is on the right. The inset zooms in around the position of Mothra. The right panel shows the profiles rescaled by a multiplicative factor to match the amplitude of the F090W profile at ≈42. The black dotted line shows a power-law model that traces the ICL with d being the distance to the BCG in arcseconds. For reference, Mothra is 63 from the BCG. The horizontal dashed lines in the inset plot show the combined effect of the PSF dilution and rescaling. A source with the same flux in all bands as in F090W that is convolved by the PSF of each band would have its amplitude at the corresponding dashed lines.