Polarisation properties in the centre of NGC253 measured at the same resolution. Distributions of pixel values of the polarisation fraction (left panel) and B field orientation (right panel). Empty histograms represent the distributions of Band 4 pixels in the images at 1.5 × 1.3″ (pink) and at 2.2 × 2.2″ resolutions (red). The solid blue and green histograms represent the distributions at Band 7. Only pixels with S/N PF/σ_PF > 3 have been used for the computation of the histograms.