Gas depletion timescale measured in an aperture centered on the maximum of the [CII] emission as a function of its radius (solid lines, see Appendix B). The colored areas correspond to the 1σ uncertainties determined using the Monte Carlo sampling described in Sect. 3. For comparison, we represent the depletion timescales measured in our two Σ_gas regions using the same symbols as in Fig. 3. The horizontal error bars correspond to the full range of angular radial distances to the [CII] maximum in the region. The high-density region systematically corresponds to the smaller radius.