CO (left) and ¹³CO (right) ladders for the whole mapped region (black), the Hii region G327.3–0.5 (red), the IRDC including the hot core (blue) and the inter-clump gas (magenta). Error bars include only calibration uncertainties. In both panels, the dashed and dotted curves represent the predicted intensities for model B from Koester et al. (1994) for a density of 10⁷ cm^-3, incident UV fields of 10³ and 10⁴ relative to the average interstellar field, a visual extinction of 10, and a Doppler broadening of 3 (dashed curve) and 1 km s^-1 (dotted curve).