The Galactic centre region observed in molecular line and dust emissions. Left panel: CHIMPS 2 longitude-velocity diagram of ¹²CO 3–2 intensity integrated over |b| < 0.5° Galactic latitude (Eden et al. 2020). Solid and dashed red lines indicate the observed longitude range for G1.3 and G1.6, respectively. Right panels: Longitude-latitude maps of the CMZ observed in warm dust emission with Hi-Gal/Herschel (top, Molinari et al. 2016) and in ¹²CO 3–2 emission observed as part of the CHIMPS 2 survey (bottom, Eden et al. 2020). The regions of G1.3 and G1.6 that were covered during our IRAM 30m observations are indicated in black.