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TANAMI monitoring of Centaurus A: The complex dynamics in the inner parsec of an extragalactic jet

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TANAMI monitoring of Centaurus A: The complex dynamics in the inner parsec of an extragalactic jet

dc.contributor.author	Müller, C.
dc.contributor.author	Kadler, Matthias
dc.contributor.author	Ojha, R.
dc.contributor.author	Perucho Pla, Manuel
dc.contributor.author	Grossberger, C.
dc.contributor.author	Ros Ibarra, Eduardo
dc.contributor.author	Wilms, J.
dc.contributor.author	Blanchard, J.
dc.contributor.author	Böck, M.
dc.contributor.author	Carpenter, B.
dc.contributor.author	Dutka, M.
dc.contributor.author	Edwards, P.G.
dc.contributor.author	Hase, H.
dc.contributor.author	Horiuchi, S.
dc.contributor.author	Kreikenbohm, A.
dc.contributor.author	Lovell, J.E.J.
dc.contributor.author	Markowitz, A.
dc.contributor.author	Phillips, C.
dc.contributor.author	Plötz, C.
dc.contributor.author	Pursimo, T.
dc.contributor.author	Quick, J.
dc.contributor.author	Rothschild, R. E.
dc.contributor.author	Schulz, R.
dc.contributor.author	Steinbring, T.
dc.contributor.author	Stevens, J.
dc.contributor.author	Trüstedt, J.
dc.contributor.author	Tzioumis, A.K.
dc.date.accessioned	2017-07-06T13:17:24Z
dc.date.available	2017-07-06T13:17:24Z
dc.date.issued	2014
dc.identifier.citation	Müller, C. Kadler, Matthias Ojha, R. Perucho Pla, Manuel Grossberger, C. Ros Ibarra, Eduardo Wilms, J. Blanchard, J. Böck, M. Carpenter, B. Dutka, M. Edwards, P.G. Hase, H. Horiuchi, S. Kreikenbohm, A. Lovell, J.E.J. Markowitz, A. Phillips, C. Plötz, C. Pursimo, T. Quick, J. Rothschild, R. E. Schulz, R. Steinbring, T. Stevens, J. Trüstedt, J. Tzioumis, A.K. 2014 TANAMI monitoring of Centaurus A: The complex dynamics in the inner parsec of an extragalactic jet Astronomy and Astrophysics 569 A115 1 16
dc.identifier.uri	http://hdl.handle.net/10550/59367
dc.description.abstract	Context. Centaurus A (Cen A) is the closest radio-loud active galactic nucleus. Very Long Baseline Interferometry (VLBI) enables us to study the spectral and kinematic behavior of the radio jet¿counterjet system on milliarcsecond scales, providing essential information for jet emission and propagation models. Aims. In the framework of the TANAMI monitoring, we investigate the kinematics and complex structure of Cen A on subparsec scales. We have been studying the evolution of the central parsec jet structure of Cen A for over 3.5 years. The proper motion analysis of individual jet components allows us to constrain jet formation and propagation and to test the proposed correlation of increased high-energy flux with jet ejection events. Cen A is an exceptional laboratory for such a detailed study because its proximity translates to unrivaled linear resolution, where one milliarcsecond corresponds to 0.018 pc. Methods. As a target of the southern-hemisphere VLBI monitoring program TANAMI, observations of Cen A are done approximately 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. Results. The first seven epochs of high-resolution TANAMI VLBI observations at 8.4 GHz of Cen A are presented, resolving the jet on (sub-)milliarcsecond scales. They show a differential motion of the subparsec scale jet with significantly higher component speeds farther downstream where the jet becomes optically thin. We determined apparent component speeds within a range of 0.1c to 0.3c and identified long-term stable features. In combination with the jet-to-counterjet ratio, we can constrain the angle to the line of sight to theta approx 12deg-45deg. Conclusions. The high-resolution kinematics are best explained by a spine-sheath structure supported by the downstream acceleration occurring where the jet becomes optically thin. On top of the underlying, continuous flow, TANAMI observations clearly resolve individual jet features. The flow appears to be interrupted by an obstacle causing a local decrease in surface brightness and circumfluent jet behavior. We propose a jet-star interaction scenario to explain this appearance. The comparison of jet ejection times to high X-ray flux phases yields a partial overlap of the onset of the X-ray emission and increasing jet activity, but the limited data do not support a robust correlation.
dc.language.iso	eng
dc.relation.ispartof	Astronomy and Astrophysics, 2014, vol. 569, num. A115, p. 1-16
dc.subject	Astrofísica
dc.subject	Astronomia
dc.title	TANAMI monitoring of Centaurus A: The complex dynamics in the inner parsec of an extragalactic jet
dc.type	journal article	es_ES
dc.date.updated	2017-07-06T13:17:24Z
dc.identifier.doi	10.1051/0004-6361/201423948
dc.identifier.idgrec	099850
dc.rights.accessRights	open access	es_ES