Mass-weighted probability density function (PDF) of the CHEM_MHD and CHEM_HD simulations (Table 1) at t = 196 Myr. The thick lines are for the CMZ (R < 500 pc), while the thin lines are for the entire simulation. Each curve is normalised so that ∫(dM/d log n) d log n = 1. In the CHEM_HD simulation, most of the gas in the ring accumulates at the highest densities purely due to orbital convergence. This is not due to the gas self-gravity, since it is switched off in our simulations. The presence of magnetic fields shifts the peak to lower densities by providing pressure support and driving random motions. The total distribution is bimodal, as expected from a two-phase medium (e.g. Seta & Federrath 2022).