Azimuthally averaged surface brightness of NGC 3311. Left panel: Surface brightness profiles (top panel) in the g (blue points) and r (red points) bands, and g − r colour profile (bottom panel). The dashed green line marks the limit of the surface brightness profiles obtained for NGC 3311 by Arnaboldi et al. (2012). Right panel: g-band surface brightness profile in logarithmic radius (top panel), with the best 1D multi-component fit (see text for details). In the lower panel, we show the Δrms residual of the data minus the model (see text for details).