Expected N₂H⁺ (7–6) line peak temperatures T_mb(N₂H⁺ (7–6)) (top panel) and ratios respect the (1–0) transition (bottom panel) at densities n(H₂) between 10⁵ and 10⁸ cm⁻³ and gas kinetic temperatures of T_K = 15 K (blue), 25 K (orange), and 35 K (red) predicted by our RADEX simulations (van der Tak et al. 2007). The typical values found in OMC-1 South (red dashed line) and OMC-1 Ridge (orange dotted line) are indicated in both plots.