Panel a: map of the emission integrated over the ¹³CO(2–1) line (solid contours) overlaid on an image of the continuum emission at 24 μm (from Molinari et al. 2008b). The latter has an angular resolution of 6′′. The ¹³ CO map was obtained with the IRAM 30-m data at a resolution of 12′′ (the beam is shown in the bottom left corner). Solid contour levels range from 20 to 84 in steps of 8 K km s⁻¹. The dotted contours represent a map of the 3.6 cm continuum emission imaged with the VLA Molinari et al. (2002) and range from 0.5 to 2.3 in steps of 0.3 mJy beam⁻¹. The synthesized beam is 10′′.2 × 9′′.0 with PA = −59°. Panel b: same as top panel, where solid contours are a map of the emission averaged over the ¹³ CO(2–1) line, obtained after merging the NOEMA with the IRAM 30-m data. The resulting synthesized beam is 0′′. 49×0′′.44 with PA = 57° (shown in the bottom left corner). The circle corresponds to the half-power beam width of the NOEMA antennas. The contour levels range from 36 to 144 in steps of 18 mJy beam⁻¹.