Channel maps (colour scale) of the NaCl v = 0J = 24−23 emission at 312 GHz at a 1 km s^-1 velocity resolution for the central 0.̋8 × 0.̋8 field around “VY” and “C”. Grey contours are the integrated NaCl line strength at (1,2,3,4) × 1 Jy/beam km s^-1, red contours are the dust continuum measured with ALMA at 321 GHz at (1,2,3,4) × 18 mJy/beam (Richards et al. 2014; O’Gorman et al. 2015). The stellar position “VY” is indicated with a white cross, and the peak of the continuum emission “C” is indicated with a white plus-sign. The ordinate and co-ordinate axis give the offset of the right ascension and declination, respectively, in units of milli-arcseconds.