Continuum-subtracted spectra of ¹²CO J = 6−5 (red lines) and ¹⁷CO J = 6−5 (blue lines). The spectra are extracted from regions with >5σ detections in ¹²CO. The yellow shaded region indicates velocities affected by foreground absorption. The vertical dashed line at 4.55 km s^-1 gives v_source. Dotted horizontal lines show the 3σ detection level. Top panel: total spectrum. The spectrum of ¹²CO mirrored on v_source is given in black line. Center panel: spectrum extracted from the east/blue part of the disk. Bottom panel: spectrum extracted from the west/red part of the disk.