CH₃CHO and HDO line profiles in T_b scale (with a spectral resolution of 1 km s⁻¹) observed during ALMA Cycle 1 and 4 (right panels) operations. Species, transitions, and upper level excitations (E_u in K) are reported (see Table 1). The vertical dashed line stands for the systemic velocity v_sys = +1.7 km s⁻¹ (e.g. Lee et al. 2014). Red curves are Gaussian fits, the results of which are reported in Table 1. In some of the panels, vertical red segments indicate an additional CH₃CHO line close to that centred at v_sys. The CH₂DOH labels (see also the magenta profile in the upper left panel, residual of the (18_5,14 –17_5,13)A and (18_5,13–17_5,12)A fit) are for emission lines of deuterated methanol, published by Bianchi et al. (2017). Some unidentified lines (U labels) are also reported.