Free electron temperature (T_e; upper panels) and H⁺ number density ($n_{H^{+}}$; lower panels) as a function of the hydrogen column density (N_H). We show CLOUDY models log U = −4.00, log n = 3.00, Z = 0.5 5 Z_⊙ (left) and log U = −2.00, log n = 1.00, Z = 0.5 5 Z_⊙ (right). These models represent typical ISM conditions for the ALPINE galaxies (Table 3). Solid and dashed lines represent the temperature and density profiles obtained for different SFHs. Red lines represent SB99 models, and blue lines BPASS models.