Spectral Properties of the Core and the VLBI-Jets of Cygnus A

Bach, U.; Krichbaum, T. P.; Middelberg, E.; Kadler, M.; Alef, W.; Witzel, A.; Zensus, J. A.

Spectral Properties of the Core and the VLBI-Jets of Cygnus A

Authors

Description

We present a detailed VLBI study of the spectral properties of the inner core region of the radio galaxy Cygnus A at 5 GHz, 15 GHz, 22 GHz, 43 GHz and 86 GHz. Our observations include an epoch using phase-referencing at 15 GHz and 22 GHz and the first successful VLBI observations of Cygnus A at 86 GHz. We find a pronounced two-sided jet structure, with a steep spectrum along the jet and an inverted spectrum towards the counter-jet. The inverted spectrum and the frequency-dependent jet-to-counter-jet ratio suggest that the inner counter-jet is covered by a circum-nuclear absorber as it is proposed by the unified scheme.
2 pages, 2 figures, Proceedings of the 7th EVN Symposium held in Toledo, Spain in October 2004, needs evn2004.cls