Publications of the MPIfR
Optical & Infrared
Interferometry Group
Britzen, S.; Witzel, A.; Krichbaum, T.
P.; Beckert, T.; Campbell, R. M.; Schalinski, C.; Campbell, J.
The radio structure of S5 1803+784
Monthly Notices of the Royal Astronomical Society,
Volume 362, Issue 3, pp. 966-974
Abstract
The BL Lacertae object S5 1803+784 has been monitored with very long
baseline interferometry at λ= 3.6 cm in 43 epochs between 1986.21 and
1993.95. The motivation of this work is to obtain statistically
meaningful data with which to study the short-term structural
variability in the source on monthly time-scales. We present a detailed
analysis of the structural evolution seen in the milliarcsecond-scale
jet by way of model-fitting results. Within the simplest identification
scenario, the jet can be described as a bent chain of seven jet
components within 0.2- and 3-mas separation from the core. New
components seem to emerge almost regularly (every 2 yr) from the core.
Three jet components approach the brightest and so-called `stationary'
component (at ~1.4 mas at 8.4 GHz) with apparent superluminal motion of
8-11c. In this paper, we show that the `stationary' component (under
the assumption that this is the brightest jet component in each epoch)
oscillates, and we discuss several possible explanations. We show that
a reconfinement shock can easily reproduce the observed most recent
oscillation of the `stationary' component. We present evidence that the
average jet ridge line is significantly curved and discuss the
possibility that the jet components follow a helically bent path.
You can get this publication ...