ALMA NaCl 312 GHz channel map at 25 km s^-1 (colour scale) overlaid with the HST/WFPC2 F1042M data of Smith et al. (2001) (in contours at (1,2,4,8,16) × 110 counts). The cross sign indicates the position of the central star VY CMa, noted “VY” in the text, as derived from the ALMA H₂O maser and continuum data (Richards et al. 2014; O’Gorman et al. 2015), the plus-sign indicates the maximum of the ALMA dust continuum data, noted as “C” in the text, (O’Gorman et al. 2015). The nomenclature of the different spatial regions refers to the northern clump ’NB’, the southern clump ’SB’, the brightest part of the south-western extension ’SW1’, and the faintest part of the north-western extension“SW2”. The ordinate and co-ordinate axis give the offset of the right ascension and declination, respectively, in units of arcseconds.