Median radial distribution (diamonds) of the radiation field (grey) in the neutral clouds (upper panel) and the fractional ISM phase contributions (lower panel) for galaxies in REF-L0100N1504. There is a peak of neutral atomic gas contribution in the centre, the DIG contribution dominates beyond three times the half-mass radius (R₅₀) of the galaxies, and the dense molecular gas contribution peaks around 0.5R₅₀ and then decreases slowly. The peak of the radiation field is similar to the one of the dense molecular gas. Shaded colour shows the coverage between the 25th and 75th percentiles.