Observed positions (except positions in OMC1) as white circles with a FWHM of 45″ on [¹²C II], ¹²CO(2–1), and ¹³CO(2–1) maps at 45″. The black rectangle outlines the region of OMC1, shown as a zoom-in in Fig. 2. The red circle outlines M43. The yellow and orange stars mark the positions of θ¹ Ori C and θ² Ori A, respectively, the pink star marks NU Ori, the purple star marks 42 Orionis.