VLBI observations of helical jets: Hints on the nature of radio-jets
Paper in proceeding, 2012

We make use of VLBI observations of the radio jet in the quasar S5 0836+710 at different frequencies and epochs to study its properties. The jet shows helical structure at all frequencies. The ridge-line of the emission in the jet coincides at all frequencies and epochs, within the errors. We conclude that the helicity is a real, physical structure. Small differences between epochs reveal wave-like motion of the ridge-line transversal to the jet propagation axis. These transversal motions are measured to be superluminal. This unphysical result could correspond to a possible small amplitude oscillation of the ridge-line at the radio-core and to large errors in the determination of the positions. In addition, higher resolution images at 15 GHz show that the ridge-line does not coincide exactly with the centre of the radio jet. At arc-second scales, this powerful jet shows non-collimated, irregular structure and a lack of a hot-spot. Following this collection of evidence, we conclude that the ridge-line could be related to a pressure maximum within the jet cross-section, associated with the observed helical pattern that could lead to jet disruption at longer scales.


Manel Perucho

Universitat de Valencia

Yuri Y. Kovalev

Astro Space Center of Lebedev Physical Institute

Philip Hardee

University of Alabama

Andrei P. Lobanov

Max-Planck Institute for Radio Astronomy

Ivan Agudo

Spanish National Research Council (CSIC)

Ivan Marti-Vidal

Chalmers, Earth and Space Sciences, Onsala Space Observatory

Proceedings of Science

18248039 (eISSN)

Vol. 2012-October

11th European VLBI Network Symposium and Users Meeting, EVN Symposium 2012
Bordeaux, France,

Subject Categories

Subatomic Physics

Fluid Mechanics and Acoustics

Fusion, Plasma and Space Physics

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