Location of the fields covered by our CO observations on the larger-scale radio continuum image at 1442.5 MHz, taken from Giacani et al. (1997). The wedges indicate the intensity of the continuum in Jy/beam. Left panel: entire SNR, right panel: zoom in the regions W44E and W44F. The inserts show the distribution of the CO (6–5) emission, integrated between 20 km s^-1 and 70 km s^-1, for which the colourscale is in the range 0–50 K km s^-1, and the contours are radio continuum in steps of 10 mJy. The size of the zoombox is ~10.3 × 12.4 pc.