Stacked RRL images of G15.1 (also known as M17). The left, middle, and right panels present the zeroth-, first-, and second-moment maps (integrated emission, intensity-weighted peak velocity, and intensity-weighted line width) for the velocity range [−40, 50] km s^-1, respectively. The beam size of 40′′ is shown in the bottom left corner of each panel. The contours show the 870 μm continuum data from the ATLASGAL survey starting at a 4σ level of 200 mJy beam^-1. The left panel gives a linear scale-bar, and the middle panel includes numbers indicating the positions of the extracted spectra presented in Fig. 12.