Trends between the fraction of [CII] emission coming from the inner CGM (f_[CII]; see Eq. 4) and the properties of the merging systems, such as the projected distance (r_p) between the galaxies (left), the stellar mass ratio (μ_⋆, middle), and the [CII] emission ratio (μ_[CII], right). We show the results obtained when adopting different apertures (1″ orange border, and FWHM-based green border) needed to define the [CII] emission associated with each component of the merger. Filled green pentagons are the estimates obtained after applying the correction for the tails of the ALMA PSF (see Sect. 3 for a discussion). In each panel, the green solid line and shaded areas are respectively the linear fit and the associated error for the more conservative estimates, and we specify the Spearman coefficient (ρ) of the corresponding relation. The horizontal dot-dashed black line indicates the 0.5 value and the system DC_873321 is highlighted in gray (see text).