TANAMI monitoring of Centaurus A (Müller et al.)
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Published on 22 September 2014
Vol. 569
In section 10. Planets and planetary systems
TANAMI monitoring of Centaurus A: The complex dynamics
in the inner parsec of an extragalactic jet
by C. Müller, M. Kadler, R. Ojha, et al. A&A 569, A115
VLBI monitoring has revealed striking structures on subparsec scales
in the radio jet of Centaurus A (Cen A).
The proper motions over 3.5 years of individual jet
components have been followed every six
months at 8.4 GHz with the Australian Long Baseline Array (LBA) and
associated telescopes in Antarctica, Chile, New Zealand and South
Africa, complemented by quasi-simultaneous 22.3 GHz observations.
They show apparent component speeds within 0.1c to 0.3c, with
some varying higher speed differential motions superposed on a long-term stable feature. The interpretation is in terms of a spine-sheath structure with
a faster inner jet and downstream acceleration where the jet becomes optically thin. The flow appears to be interrupted by an obstacle
causing a local decrease in surface brightness and circumfluent jet
behavior. A jet-star interaction could explain these features.