The best-fit lensing model for the continuum and [C II] line emission. From left to right: the observed dirty image, the modeled dirty image, and the source plane emission. The red lines mark the caustics of the best-fit lensing models. The best-fit lensing configuration for the continuum emission and the [C II] line differ significantly, essentially ruling out the strong lensing hypothesis for J2037–4537.