Neutral carbon toward d203-506. Upper: [C I] 609 μm and C¹⁸O J = 3–2 line profiles. The gray-shaded spectrum shows HCO⁺J = 4–3 (Berné et al. 2024) scaled and convolved to the angular resolution of the [C I] 609 μm observations. Lower: NIR detection of [C I] forbidden lines at 0.9827 and 0.9853 μm (top) and C I permitted line multiplets at ∼1.069, ∼1.176, and ∼1.355 μm (bottom). Magenta lines represent the position and relative local thermodynamic equilibrium (LTE) intensity of each component.