Scaling relations for r′-band Sérsic-derived quantities from Sérsic+PSF decompositions. Column 1: g′−r′ colour, r′−i′ colour, Sérsic index, effective radius (in arcsec), and mean effective surface brightness (in mag arcsec⁻²) as a function of stellar mass, between Fornax main (blue) and Fornax group (orange) galaxies. Column 2: similar to Col. 1, but split between ETGs (red crosses) and LTGs (dark blue crosses). The solid black lines denote the moving averages (median) based on moving a fixed-size bin through increasing stellar mass to find the mass dependence in each parameter. The vertical grey dashed line denotes log₁₀(M_*/M_⊙) = 6. Column 3: residual parameters (i.e. parameters minus derived mass-trend from moving averages) as a function of mass. The solid lines denote the median residual value within stellar mass bins of width 1 dex for the Fornax main (blue) and Fornax group (orange) sub-samples, respectively. Galaxies with log₁₀(M_*/M_⊙) < 6 were excluded due to incompleteness in the sample. Column 4: distribution of the residual parameters for the Fornax main (blue) and Fornax group (orange) sub-samples. The p-value from null hypothesis tests (i.e. both sub-samples are drawn from the same distribution) are annotated in the plot, indicating the probability that both distributions are drawn from the same sample.