Star-formation rate surface density as a function of molecular gas-mass surface density in J2345−0449. The red dot indicates the position of J2345−0449 for the average gas mass and star-formation rate surface densities, Σ_gas = 78 M_⊙ pc² and Σ_SFR = 1.9 × 10⁻³ M_⊙ yr⁻¹ kpc⁻², respectively. Small black dots indicate the position of the source if 25% or 50% of the CO(1−0) line flux come from optically thin gas. Dotted vertical lines indicate the correction that would be necessary if J2345−0449 had the same fraction of optically thin gas as NGC 1266 and IC 5063. The error bar in star-formation rate takes into account the systematic differences between star-formation rate tracers discussed in Sect. 3.3, including in particular the SFR = 2.95 M_⊙ yr⁻¹ estimated from WISE at 22 μm by Dabhade et al. (2020).