Properties of two synthetic merging systems with high (μ_⋆ = 4.1, H2, left panels) and low (μ_⋆ = 1.3, H10, right panels) stellar mass ratios at z = 4.5. First row: Maps of the stellar surface density projected along a line-of-sight parallel to the x-axis. Stellar particles are color-coded according to their age, with age ≤ 10 Myr in dark blue, age ≤ 100 Myr in light blue, and 100 Myr < age ≤ 1 Gyr in red color scale. Second row: Same as above, but for the carbon surface density distribution of H10 (μ_C = 3.6) and H2 (μ_C = 1.5), respectively. The green color map shows the total carbon surface density distribution and overplotted on that, in orange tones, is the carbon distribution in the cold gas phase (i.e., with T < 5 × 10⁴ K). Third row: Carbon in the cold gas phase surface density distribution once we convolve the original simulated map with the ALMA PSF. Black ellipses indicate the FWHM-based apertures used to extract the carbon content associated with each merging galaxy. In the bottom left corner is a beam of ∼1″ as a reference. Black (first row) and white (second and third rows) dashed contours indicate the positive significant level at 2σ.