Top panels: integrated ¹³CO(3–2) line of the ring G345.50+1.50 between −30 and −2 km s^-1 (panel A)), between −26 and −24 km s^-1 (panel B)), and between −22 and −2 km s^-1 (panel C)). The black circles in the bottom left corner represent the APEX beamsize at 330.588 GHz, ~18′′. Contours show the emission integrated between −30 and −2 km s^-1 with levels of 9, 18, 36, 72, and 144 K km s^-1. In panel A), the ellipse indicates the expanding ring model in the X–Y plane, the lines show the filaments, and the circle plots the outflow IRAS 16562-3959. Panels D)–F) show the ¹²CO(3−2) and ¹³CO(3−2) spectra toward the positions P1, P2, and P3, respectively, indicated in panel A) with the arrows.