Column density maps of different species in the simulated galaxy after post-processing. The total hydrogen and H₂ from the simulation are shown in the first two panels. The remaining panels show the column density of H₂, C⁺ , C, and CO obtained via post-processing. The H₂ from post-processing (top row, third panel) is remarkably similar to the H₂ from the simulation (top row, second panel). CO dominates the carbon budget in the highest $N_{{\text{H}}_2}$ regions and is essentially absent when $N_{{\text{H}}_2}\lesssim {10}^{21}$ cm⁻². Atomic carbon traces the full extent of the H₂ distribution, while C⁺ extends farther out to regions devoid of a significant amount of H₂.