Three-color map of the G323.18+0.15 complex (right) and nearby HII regions (left). Left: red, green, and blue background shows 21 cm, 8 µm, and 4.5 µm emission, respectively. The white circles are the HII regions identified by Anderson et al. (2014). The white rectangular box is the research region, a zoom of which is shown in the right panel. The white contours are the integral intensity of the ¹³CO emission from −69 to −61 km s⁻¹ in the G323.18+0.15 complex. The white crosses and yellow triangles are class I and II YSOs, respectively. Right: same as the left panel, but the dashed green circles are the area for which the surface density was calculated (see Sect. 4.2).