Best-fit two-component model of G09v1.97-R for (a) the H₂O lines and (b) the dust continuum (colored symbols and lines) compared with observations (black symbols with error bars). Predictions for the two individual ISM components are displayed with dashed green (the disk component) and blue lines (the core component); the total is shown in red. The physical parameters adopted from this model are indicated with arrows in Fig. 4. Panel a: numbers indicate the rest frequencies of the lines in GHz. The observed H₂O fluxes and continuum flux densities have been corrected for magnification. The continuum fluxes have also been corrected to only account for the contribution by G09v1.97-R, as described in Sect. 2 (see also Y19).