of the interpretation is in the context of a jet and bipolar outflow. The position angle of the jet is $-16\pm1^{\circ}$, whereas the PA of the CO lobes is about $-6^{\circ}$ and the PA of the line joining N-1 and S-1 is $-16^{\circ}$. We adopt a nominal angle for the jet outflow of $-16^{\circ}$.

The central jet source
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An important difference with respect to the analysis of Rodríguez et al. (2005) is that we recognize the presence of a compact source (source D) very close to the jet source (see Fig. 2), about $1\rlap.{''}2$ to its NW. To obtain the parameters of the jet and of source D separately we fitted simultaneously two Gaussian ellipsoids to this region of the image. The jet parameters for the two epochs discussed are given in Table 1. We note that the consideration of source D in the fitting procedure results in somewhat smaller deconvolved dimensions for the minor axis of the jet than obtained in Rodríguez et al. (2005). We assume that the opening angle of the thermal jet is the angle subtended by the deconvolved minor axis at a distance of one-half the deconvolved major axis (Eislöffel et al. 2000). Using 