Characterizing the starlight distribution of NGC 1316: W1 image (left panel) and GALFIT residual maps for a single Sérsic + PSF model (middle panel), and a double Sérsic model + PSF model (right panel). The contour levels of the W1 image increase from 10 to 640 μJy/pixel in steps of a factor of 2; they are ± 1 μJy/pixel in the residual maps (positive contour in black, negative one in white). The best-fit parameters are in Table 4. The double Sérsic model gives lower residuals and will be used to represent the starlight distribution of NGC 1316 in all WISE bands.