Left: H₂CO 3₀₃–2₀₂ line emission detected by the SMA integrated between 0 and +9 km s^-1. Middle: H₂CO 3₀₃–2₀₂ line emission observed by the APEX telescope in a 7 × 7 grid integrated between 0 and +9 km s^-1. Right: H₂CO 3₀₃–2₀₂ line emission in the combined SMA interferometry and APEX short-spacing data integrated between 0 and +9 km s^-1. Contours are at 2.5 Jy beam^-1 km s^-1 levels (converted to SMA beams,  ~5σ at the edge of the SMA primary beam) in all three maps. Negative intensities are represented by dashed contours. Coordinates are offsets from the central position of IRS7B. Refer to Fig. 1 for a guide to the symbols used for the compact objects.