Total integrated intensity maps of the ¹³CO (3−2) (left panels) and C¹⁸O (3−2) (right panels) lines produced with natural (upper panels) and uniform (lower panels) visibility weighting functions. Note that the upper panels show the whole area of the G 19.61−0.23 star-forming region, while the lower panels magnify the region centered on the HMC (greyscale plus thin contour; see Table 2). For comparison purposes, the 7σ level contour of the 6 cm continuum (i.e., free-free) emission as in Fig. 1a is shown by thin green contours. The magenta stars indicate the peak positions of the three 890 μm continuum sources (Table 3). The contours of the CO isotopomer maps start from the 5σ level in steps of 3σ, where the 1σ noise levels are 1.9 and 1.8 Jy beam^-1 km s^-1 for the natural and uniform weighted ¹³CO maps, and 0.8 Jy and 1.7 beam^-1 km s^-1 for the natural and uniform weighted C¹⁸O maps, respectively. We integrated the emission over the LSR-velocity ranges 30.2  ≤  V_LSR/km s^-1  ≤  42.2 for ¹³CO, and 34.7  ≤  V_LSR/km s^-1  ≤  44.5 for C¹⁸O. All the other symbols are the same as those in Fig. 1. The emission seen in the top of the upper-panels is an artifact caused in the cleaning process.