SIMBAD references

High-resolution VLBI observations at 10.7GHz are presented for four epochs between 1988.17 and 1991.17. Three superluminal components, not seen in previous maps at this frequency, were detected. The ejection times of two of these are well correlated with the occurrence of strong flares at radio and infrared wavelengths. The third component was short-lived, and was detected only in the first map at a distance of 0.6 mas from the core. Differences in velocity, combined with the existence of short-lived components could explain the gaps observed in the jet in lower frequency maps. The analysis of all the data available in the literature shows that the velocities of the individual components did not change with time, but varied from one component to another, in the range of v/c=4.9h^–1 to 7.7h^–1. While some components seem to follow the same curved path in the sky, two of them, first seen between 1983 and 1985 show clearly a different behaviour.