S5 0836+710 A Kelvin-Helmholtz Unstable Jet on Parsec Scales?

Abstract

The highly redshifted quasar S5 0836+710 (z = 2.172) displays an outstanding one sided jet with complex morphology. The continuous jet shows several remarkable lateral displacements (kinks) of its ridgeline on various length scales. Despite the strength of these distortions the jet is not destroyed by them and remains well collimated. We investigated the possibility to explain the displacements by Kelvin-Helmholtz instabilities.

Absolute kinematics of radio source components in the complete S5 polar cap sample

“…Its change in morphology is associated with the strong decrease in flux density of one of the components from the first to the second epoch. QSO 0836+710 and QSO 1928+738 show the familiar changes in structure produced by emerging components in a core-jet system, as reported by Otterbein et al (1998) for the former, and Hummel et al (1992a) for the latter. The BL Lac object 2007+777 displays an interesting, and hard to explain change in position angle towards north for components near to the core, a fact also reported by Krichbaum et al (2000) from 5 GHz VSOP observations.…”

“…9. We can neither confirm nor reject the superluminal motion reported by Otterbein et al (1998), until an astrometric registration between our both images becomes available. Only from our model fitting it is difficult to establish proper motions between components (Table 2).…”

“…epoch 1992.65, with an apparent superluminal motion of µ = 0.26 ± 0.03 mas yr −1 . The ejection of this component would be directly related to gamma-, X-ray, and optical activity observed in February 1992 (Otterbein et al 1998). …”

“…The structure of the jet can be characterized by a sequence of kinks among which the jet follows a slightly curved path (Krichbaum et al 1990). Based on data at 8.4, 15, 22, and 86 GHz, Otterbein et al (1998) Table 1 for contour levels, synthesized beam sizes (bottom left in the maps), and peak flux densities. See Table 2 for component parametrization.…”

Long-term multiwavelength studies of high-redshift blazar 0836+710

“…It hosts a powerful one-sided radio jet emerging from the core and extending up to kiloparsec scales (Hummel et al 1992). Very Long Baseline Interferometry (VLBI) images of the source show a complex motion pattern, with jet components moving from apparent subluminal to superluminal velocities (Otterbein et al 1998). Monitoring with MOJAVE (Monitoring Of Jets in Active galactic nuclei with VLBA Experiments) 1 has shown apparent jet speeds up to β app = 25 (Lister et al 2009).…”