Parameter space of RADEX models reproducing the line in- tensities and line ratios found in the NGC 2023 & NGC 2024 region, for three diverse emission components. Line ratios of models reproducing the ’typical’ emission are shown on a multi-colour scale, models corresponding to the emission component seen at ~4 km/s are shown on a red colour scale, and models reproducing the high-excitation component at the western cloud edge are shown on a blue colour scale. For each component, models for a column density in the (logarithmic) middle of the column density range reproducing the respective characteristic line ratios and intensities are shown: N = 10¹⁸ cm⁻² (typical emission), N = 2 ⋅ 10¹⁷ cm⁻² (4 km/s component), and N = 10¹⁶ cm⁻² (high-excitation component). Straight lines mark locations of constant pressure p = n ⋅ T. Top: RADEX models for the ’typical’ emission.