Mass-weighted probability density function of the gas density within a disc of 4 kpc height and 10 kpc radius, centered on the G9 galaxy, for the different runs, at t = 100 Myr (top panel) and t = 250 Myr (bottom panel) throughout the simulations as indicated. The vertical black dashed line shows the density threshold for star formation. Because it adds an additional pressure support against gravity that cools less efficiently than thermal pressure, CR injection reduces the high-density tail of the probability density function and increases the low-density tail.