Spectra of the integrated CN (2–1) emission from the upper intermediate layers, lower intermediate layers, midplane, and outer midplane regions of the disk along with the simultaneous fits to components A, B, and C (see Table 3). The best-fit LVG models from the χ² minimization are displayed as a green line. The fitted parameters are the total optical depth (τ; A+B+C), excitation temperature (T_ex), and, on a logarithmic scale, CN column density (N_CN) and particle density (; see Table 4). Spectra in the left and right columns are extracted from the western and eastern sides of the disk, respectively. The fit residuals are shown as a function of frequency at the bottom of each panel. The shaded gray area shows the error computed from a signal-free part of the spectra.