Deconvolved size (in arcsec) for different molecular transitions (listed in Table 1) versus the upper level energy of the transition for cores A (top panel) and B (bottom panel). In both panels, black circles correspond to CH₃CN, open circles to CH₃CN vibrationally excited, red pentagons to CH₃OH, and blue stars to transitions of other molecules. The typical error in size is shown in the top panel.