Top left: integrated spectra of the ¹²CO(3−2) emission line. Top right: integrated spectra of the ¹³CO(3−2) emission line. The integration surfaces correspond to areas where emission is above 5σ on the corresponding integrated maps presented in Fig. 1. Bottom left: first moment of the ¹²CO(3−2) emission line. The black arrow indicates the PA of the disk as seen in ¹²CO. The latter is used to build the PV diagram shown in Fig. 3. The red and blue arrows represent the jet axis of Th 28, while the line-of-sight vectors represent their rotation sense in optical tracers derived by Coffey et al. (2004). Bottom right: first moment of the ¹³CO(3−2) emission line. In these two first-moment maps, a clear velocity gradient due to the rotation of the circumstellar disk of Th 28 is seen.