Same as Fig. 1, but for two specific systems: (a) DC_818760 (top-left) and (b) vc_5101209780 (top-right). The white contour indicates the positive significant level at 2σ of [CII] flux, where σ_[CII] = 84 mJy km/s in (a) and σ_[CII] = 95 mJy km/s in (b). The dashed black ellipses indicate the FWHM_x × FWHM_y regions obtained by 2D Gaussian models and correspond to the apertures used to extract the [CII] spectra of (a) and (b). Finally, the black crosses mark the center of each ellipse (i.e., center of each galaxy). The ALMA beam size is given in the bottom-left corners. The lower panel shows the [CII] spectra for each component of the merging system (different line styles) extracted using 1″ (orange), FWHM-based (green), and peak apertures (pink).