MERLIN observations

In 1988 a series of seven MERLIN images were obtained by Spencer et al. (1992). The observations were made at a wavelength of 18 cm, at intervals of two to three weeks. The resolution of these images is cm, typically enough to show substantial compact emission.

During this period two knots were formed. They are linked to flaring episodes. The brightness of these knots decayes with a 1/e time of days. VLBI knots decay more rapidly. The brightness temperature of the MERLIN knots is K, compared to K for VLBI knots. A possible explanation for these observations is that VLBI knots are related directly to individual flares, whereas MERLIN knots may consist of a number of flares, ejected over a certain period of time. Between the bright knots, a substantial amount of continuous emission can been seen in MERLIN maps. It is not clear if this emission also exists at low level on VLBI scales ( cm), or whether it is formed at larger distances from the core.