Radial SB profiles of the modelled Lyα distribution decomposed into central (green lines) and extended (blue lines) exponential components. These are the same objects as in Figs. 2 and 3. The total radial SB profiles of the modelled Lyα emission are shown in red. For comparison, the observed radial SB profiles are overplotted as black points. The fit is performed on the 2D Lyα NB image and not on the 1D radial SB profiles shown. The best-fit scale lengths are indicated in physical kpc. Upper limits and detection limits are also indicated (see Sect. 4.3.2).