Cross-correlation function (CCF) between the observational residuals (i.e., data minus model without ¹³CO) and the ¹³CO model template (i.e., model with ¹³CO minus model without ¹³CO) for the two highest resolution data sets (GRAVITY and SINFONI). The sum of all CCFs is shown in blue, while the CCFs for GRAVITY and SINFONI are shown in red and orange, respectively. The auto-correlation function (dashed-black) has been re-normalized to the peak of the CCF. The CCF has been computed between 2.33–2.40 µm with a skipedge of 50 bins to properly cover the two ¹³CO band heads. The S/N corresponds to that of the central peak and was computed using equation (1) of Houllé et al. (2021) for each individual CCF, then propagated.