Constraints on the temperature and electron density for gas associated with Orion’s Veil. The dashed lines show the constraints on the gas properties derived from different observables: the transition of the CRRLs from emission to absorption between n = 200 and 279 (purple); theratio of the integrated optical depths of the C280α and C351α lines (light blue); the ratio of the C351α velocity integrated optical depth to the 158μm-[CII] line intensity(green). All the constraints shown are 3σ ranges. The region where the constraints overlap is shown as a yellow shaded region, close to 0.9 cm⁻³ and 40 K.