Spatial distribution of the mass of dense gas (left), the gas mass in the PL part of the N-PDF (middle) and the 24 μm surface brightness in our M51 target region. We use the 24 μm emission as a proxy for star formation. The masses are derived from the MAP estimate of the N-PDF, using Eqs. (12) and (11). The red contours are the same as in Figure 4. The masses of dense and PL gas appear highly correlated, with a similar spatial distribution as the 24 μm emission.