Spectra measured at three selected positions. The left plot shows the zero-position of the map, the central plot shows the peak of the 20 km s⁻¹ component, and the right plot shows the central pixel at the bright end of the strip (see Fig. 7). The individual spectra have been shifted vertically by 2 K relative to each other to improve the visibility. As the 36 km s⁻¹ component is not detected above the noise level for these three positions, the plotted spectral range is limited to the other two velocity components.