Our recent VLBI observations of the prominent FR II radio galaxy Cygnus A
with the EVN and the VLBA reveal a pronounced two-sided jet structure. At 5
GHz, we now have 4 epochs from 1986, 1991 (Carilli et al., 1991 & 1994), 1996
and 2002 from which we could derive the kinematics of the jet and counter-jet.
On the jet side and on mas scales, the jet seems to accelerate from Ξ²appββ0.1β0.2 (Krichbaum et al. 1998) at core-separations near 1 mas to
Ξ²appββ0.4β0.6 at rβ₯4 mas (H0β=100 km sβ1
Mpcβ1, q0β=0.5). For the first time we also measure significant
structural variability on the counter-jet side. For this, we derive a motion of
Ξ²appβ=0.35Β±0.2 at r=9.5 mas. The flat spectrum of the inner
region of the counter-jet (free-free absorption) and the frequency dependence
of the jet to counter-jet ratio support strong evidence for an obscuring torus
in front of the counter-jet (Bach et al. in prep, Krichbaum et al. 1998).Comment: 4 pages, 6 figures, appears in: Proceedings of the 6th European VLBI
Network Symposium held on June 25th-28th in Bonn, Germany. Edited by: E. Ros,
R.W. Porcas, A.P. Lobanov, and J.A. Zensu