Spectra measured with the IRAM 30 m telescope (Aladro et al. 2015) and the ALMA observations presented in this work. ALMA spectra were extracted at the same positions as the single-dish observations from the data cubes smoothed to 23″ resolution. For ¹³CO, C¹⁸O, and C¹⁷O, the ALMA data are shown both with their actual flux (grey histogram) and multiplied by 2.5 (red histogram) for comparison with the single dish line profiles (black line). For ¹³C¹⁸O, we show the profiles in both SD A and SD B positions in Fig. 1, for comparison with the single dish data from Aladro et al. (2015) and Martín et al. (2010), respectively. See text in Sect. 3.1.1 for details.