Continuum-subtracted H₂ 1-0S(1) images of IRS54. Panels a) and c): average over two spectral channels at − 64 km s^-1 and –30 km s^-1 (panel a)), and +40 km s^-1 and +75 km s^-1 (panel c)). Panel b): single spectral channel at +6 km s^-1. The velocities are corrected from an average cloud velocity of 3.5 km s^-1 (Wouterloot et al. 2005; André et al. 2007). Panel d): average H₂ 1-0S(1) emission over the previous velocity channels. Overplotted are the locations of six spatial regions where spectra were extracted. For reference, contours of the continuum (near the H₂ 2.122 μm line) down to the FWHM size have been overplotted at the centre of every image (dashed-blue contours). Contours in all panels show values of 1.3, 2.9, 4.5, 5.3, 6.1, 7.7, 9.3 × 10^-14 erg s^-1 cm^-2μm^-1.