Upper panel: false colour map of the CO (10−9) integrated intensity in the blue line wing (from  +2.4 km s^-1 to −30 km s^-1). The positions of HH 54 B, HH 53, and HH 52 are indicated with yellow squares. The readout positions for the on-the-fly and raster maps are indicated with white dots. Middle panel: CO (10−9) map of the integrated intensity obtained with HIFI in the blue line wing overlaid on an Hα image from Caratti o Garatti et al. (2009). Contours are from 5.5 to 33.6 K km s^-1 in steps of 3.5 K km s^-1. Lower panel: a zoom of the CO (10−9) integrated intensity overlaid on the H₂O   (2₁₂−1₀₁) emission obtained with PACS. The positions of HH 54 B, C and K as indicated in Giannini et al. (2006) are indicated with yellow squares.