Left: Spatially resolved KS relation considering ≈30 × 30 pc² pixels drawn from the entire sample of SERRA galaxies (color-coded, ground truth). For each pixel the Σ_SFR, Hα is derived from the Hα surface brightness using the Kennicutt (1998) relation, and the Σ_gas is taken from the simulation. For comparison, blue contours show the inferred location of the pixels on the KS plane assuming ${\mathrm{\Sigma }}_{\mathrm{gas}}={\alpha }_{[\mathrm{CII}]}^{\mathrm{Z}18}{\mathrm{\Sigma }}_{[\mathrm{CII}]}$, namely adopting a constant Zanella et al. (2018) conversion factor to get the gas surface density from Σ_[CII]. The location in the KS plane found when using the best-fit spatially resolved conversion factor, W_[CII] (Eq. (10)), is plotted in purple. Right: L_[CII]-weighted distribution of the depletion time (t_dep) in the SERRA pixels (shaded histogram), that inferred using ${\alpha }_{[\mathrm{CII}]}^{\mathrm{Z}18}$ to determine the Σ_gas (blue), and that obtained using the W_[CII] from Eq. (10).