Spectra extracted in a pixel toward the continuum peak positions for IRAS2A, IRAS4A-NW and IRAS4B. The identified lines are marked, including the targeted HO 3_1,3 − 2_2,0 line. Parameters from the fits are tabulated in Table A.2. The numbers above the lines and the colors correspond to the numbers (emission lines) and colors in Fig. 3, Tables 3, A.1 and A.2. The spectra have been binned to a width of 0.23 km s^-1 (i.e., 2 channels per bin), and Gaussian profiles have been fitted to the identified lines. The systemic velocity of the HO line is marked by the vertical dotted line at v_lsr = 7.0 km s^-1. Note the difference in scale of the y-axis for the spectra.