in 2.68 years or less, that at a distance of 2.9 kpc implies the unlikely velocity of $\sim10^4$ km s$^{-1}$ or more. Finally, a third possibility is that we are observing the brightening of the jet flow as it interacts with dense gas in its path. Observations of higher angular resolution are required to disentangle the nature of the variations seen in the jet source. Unfortunately, the present observations are the best that it can be done now and possibly for decades (until completion of the Square Kilometer Array). The source can be observed, but with lower angular resolution, with ATCA (as already done) but it cannot be observed from the latitude of the future e-MERLIN. Finally, the emission is thermal and not easily detectable with VLBI arrays.

The source S-1 is the one with the largest flux density variation, with an increase of $\sim$40% (see Figure 1 and Table 1) between the two epochs. We believe that this large increase is related to our suggestion that S-1 may be a working surface of the jet, where kinetic energy is rapidly being dissipated and changes are expected.

Lack of Proper Motions Along the Jet Axis
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The proper motions of 