Total integrated intensities for all detected components of the ¹²CO (left), ¹³CO (centre), and C¹⁸O (right) J = 3 → 2 lines towards IRDC F by the JCMT (in color scale). The contours give the mass surface density derived by Butler & Tan (2012) and are the same as in Fig. 1. The blue diamonds give the central locations of the F1 and F2 cores (right and left in the subfigures, respectively). The blue circle shows the HPBW of the observations.