Channel maps of C157α (top row), 158μm-[CII] (middle row), and ¹²CO(2–1) (bottom row) line emission. The pink contours show C157α emission above 3σ in steps of 3σ, with σ being the standard deviation of the spectra (σ ≈ 10 mK). The velocity is indicated at the bottom of each panel. All cubes have been convolved to a spatial resolution of 8′.1. The velocity axes were averaged to match the velocity resolution of the C157α cube. The spatial axes are given in offset with respect to M 42. The red circle shows the extent of M 42 in the 21 cm continuum map of van der Werf et al. (2013). In the top panel with a velocity of 9.5 km s⁻¹ the background image in blue is the 857 GHz emission as observed with Planck at 4.′6 resolution (Planck Collaboration I 2016). In the top row panels with a velocity ≥ 9.5 km s⁻¹, the dashed line shows a declination of − 5.0583° (J2000), used to separate S279 from Orion A. The color scales at the right are in units of K.