log(χ²) grid for the kinetic temperature and volume density using the column density from Vastel et al. (2018) for the six species that are used for the MCMC inference. The lower value of the log(χ²) is fixed at 0 to allow a better comparison between each species while allowing a flexible upper end, as the large ranges of log(χ²) values make it difficult to create an informative figure with a single range of values.