Unsigned magnetic flux density, ⟨|B_LOS|⟩, as a function of distance to the AR centre. The ⟨|B_LOS|⟩ inside the dark halo (i.e. averaged over all dark halo patches at a certain distance to the AR centre and not treated separately) is shown in blue; the red curve shows the ⟨|B_LOS|⟩ for the bright areas in between the dark halo patches. The dashed lines show the unsigned magnetic flux density calculated with pixels below the noise level of 1σ = 7.4 G set to zero, while the solid lines denote the unsigned flux density including pixels with values below the noise level. The real ⟨|B_LOS|⟩ lies within the shaded areas indicated by these upper and lower boundaries. The mean value of the QS is shown in green.