Azimuthal asymmetry of the H₂CO 3_2,1−2_2,0 line emission. Left panel: rotational diagram analysis applied to the two regions, highlighted in the integrated intensity maps of the two lines of the H₂CO molecule: the pink region corresponds to PA = 0°, while the blue one is at PA = 180° along the major axis. The dashed pink and blue lines correspond to the best fit N_t and T_ex (reported in the top right corner) obtained for the pink and blue region, respectively. Right panel: spatially integrated spectra of the H₂CO 3_2,1–2_2,0 line in the pink region and the blue region (lines in corresponding colors). The gray error bar in the top right of the panel is the uncertainty on the spatially integrated flux derived from the non-JvM corrected cube, which is the same for each velocity bin.