Composite image of the cluster forming region, OMC-2/ FIR 3 and FIR 4, obtained with ALMA (red: carbon monoxide gas, orange: emission from the dust, blue: silicon monoxide gas). For each color, the stronger the radio wave intensity, the more whitish the color is. FIR 3 is located in the upper left of this image, while FIR 4 is located in the bottom right. The giant molecular outflow driven by the protostar in the FIR 3 region (red color) collides with the “filamentary molecular cloud” (orange color). Subsequently, outflow gas interacting with the filamentary molecular cloud is being compressed (shown in pinkish red). The outflow gas also collides with downstream dense gas (shown in orange color) where a group of baby stars is being born (green circles within the FIR 4 region). The shock layers are observed with the silicon monoxide gas (pale blue). The white bar in the lower right corner shows the scale of 4000 astronomical units (au).
Credit: ALMA (ESO/NAOJ/NRAO), A. Sato et al.