2D PDF of the spatially resolved conversion factor (W_[CII]) as a function of the spatially resolved metallicity (Z_pix) from the entire sample of SERRA sources. For comparison, we plot the theoretical estimates obtained with the ferrara2019 model assuming gas densities log(n/cm⁻³) = 3 (red) and log(n/cm⁻³) = 3.5 (cyan). We plot the results with burstiness parameters of log κ_s = 0 (solid lines), log κ_s = 0.5 (dashed lines), and log κ_s = 1.0 (dotted lines).