Mass-density MGE for FCC 153. Top: contours of the projected mass density (black), the mass density MGE_∑ (red), and the surface brightness MGE_μ (blue). Bottom: ratio between the mass and surface-brightness models, showing the structural differences. This panel is normalised by the average M_⋆/L such that values of 1.0 (white) are consistent with the assumption of a spatially-constant M_⋆/L, and any deviations are percentages in stellar mass. The outline of the MUSE mosaic is shown in dashed brown.