Different emission distributions toward DR18. Left: three-color composite image of DR18; HCO⁺ emission in red, 8 µm emission in green, and the GLOSTAR 6 cm radio continuum emission in blue. The 6 cm emission represents a combination VLA D- and B-configuration data from the GLOSTAR survey. The synthesized beam size of the GLOSTAR data is 4″, comparable to that of NOEMA data (~3–4″). The pixel size, of the Spitzer/IRAC 8 µm data is 0.″6. The black dashed lines indicate the cuts for intensity profiles of different emission tracers, presented in Fig. 15. The white rectangles represent the areas of the East and North shells, as well as the Ridge. Right: flux difference image of Brγ and H₂ 1–0 S (1) emission lines obtained from Comerón et al. (2022). The black and yellow contours show the 5σ level of N₂H⁺ velocity-integrated intensity and a 3.0σ level of SiO velocity-integrated intensity, respectively. In both images, the bright green star indicates DR18-05, the ionizing source in DR18.