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

Ros, E.; Marcaide, J. M.; Guirado, J. C.

doi:10.1051/0004-6361:20010987

Cited by 23 publications

(22 citation statements)

References 28 publications

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“…Hummel et al (1997) confirm stationarity of component B and place an upper speed limit of (0.007±0.025) mas/year. We identify eight jet components within this complicated source and confirm the results of Ros et al (2001).…”

Section: +744supporting

confidence: 82%

A multi-epoch VLBI survey of the kinematics of CJF sources

Britzen

Vermeulen

Taylor

et al. 2007

A&A

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Context. This is the first of a series of papers presenting VLBI observations of the 293 Caltech-Jodrell Bank Flat-Spectrum (hereafter CJF) sources and their analysis. Aims. One of the major goals of the CJF is to make a statistical study of the apparent velocities of the sources. Methods. We have conducted global VLBI and VLBA observations at 5 GHz since 1990, accumulating thirteen separate observing campaigns. Results. We present here an overview of the observations, give details of the data reduction and present the source parameters resulting from a model-fitting procedure. For every source at every observing epoch, an image is shown, built up by restoring the model-fitted components, convolved with the clean beam, into the residual image, which was made by Fourier transforming the visibility data after first subtracting the model-fitted components in the uv-plane. Overplotted we show symbols to represent the model components. Conclusions. We have produced VLBI images of all but 5 of the 293 sources in the complete CJF sample at several epochs and investigated the kinematics of 266 AGN.

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Section: +744supporting

confidence: 82%

A multi-epoch VLBI survey of the kinematics of CJF sources

Britzen

Vermeulen

Taylor

et al. 2007

A&A

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“…comm. ); at 8.4 GHz by Pérez-Torres et al (2000), Ros et al (2000Ros et al ( , 2001; and at 15 GHz by Pérez-Torres et al (2000, in prep. ), Kellermann et al (1998), Zensus et al (2002, Lister & Homan (2005).…”

Section: Observations and Data Reductionmentioning

confidence: 91%

The kinematics in the pc-scale jets of AGN

Britzen¹,

Kudryavtseva

Witzel³

et al. 2010

A&A

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Context. BL Lac objects show core-jet structures with features moving outwards along the jet. We present a kinematic analysis of jet component motion in the pc-scale jet of the BL Lac object S5 1803+784, which does not reveal long-term outward motion for most of the components. Aims. S5 1803+784 shows complex kinematic phenomena; understanding these provides new insights into the emission processes in BL Lac objects and possibly into the differences between quasars and BL Lac objects. Methods. The blazar S5 1803+784 has been studied with VLBI at ν = 1.6, 2. 3, 5, 8.4, and 15 GHz between 1993.88 and 2005.68 in 26 observing runs. We (re)analyzed the data and present Gaussian model-fits. We collected the already published kinematic information for this source from the literature and re-identified the components according to the new scenario presented in this paper. Altogether, 94 epochs of observations have been investigated. Results. A careful study of the long-term kinematics reveals a new picture for jet component motion in S5 1803+784. In contrast to previously discussed motion scenarios, we find that the jet structure within 12 mas of the core can most easily be described by the coexistence of several bright jet features that remain on the long-term at roughly constant core separations (in addition to the already known "stationary" jet component ∼1.4 mas) and one faint component moving with an apparent superluminal speed (∼19c, based on 3 epochs). While most of the components maintain long-term roughly constant distances from the core, we observe significant, smooth changes in their position angles. We report on an evolution of the whole jet ridge line with time over the almost 12 years of observations. The width of the jet changes periodically with a period of ∼8−9 years. We find a correlation between changes in the position angle and maxima in the total flux-density light-curves. We present evidence for a geometric origin of the observed phenomena and discuss possible models. Conclusions. We find evidence for a significantly different scenario of jet component motion in S5 1803+784 compared to the generally accepted one of outwardly moving jet components, and conclude that the observed phenomena (evolution of the jet ridge line, roughly constant component core separations but with significant position angle changes) can most easily be explained within a geometric model.

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“…2, we briefly describe the observations and the data reduction, the model fitting process and present the final Britzen et al (1999) andin prep. (2005), (2) Kellermann et al (1998) & Zensus et al (2002, (3) Jorstad et al (2001b), (4) Fey & Charlot (2000), (5) Ros et al (2001). images. In Sect.…”

Section: Introductionmentioning

confidence: 99%

Kinematic study of the blazar S5 0716+714

Bach¹,

Krichbaum²,

Ros³

et al. 2005

A&A

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116

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Abstract. We present the results of a multi-frequency study of the structural evolution of the VLBI jet in the BL Lac object 0716+714 over the last 10 years. We show VLBI images obtained at 5 GHz, 8.4 GHz, 15 GHz and 22 GHz. The milliarcsecond source structure is best described by a one-sided core-dominated jet of ∼10 mas length. Embedded jet components move superluminally with speeds ranging from 5 c to 16 c (assuming z = 0.3). Such fast superluminal motion is not typical of BL Lac objects, however it is still in the range of jet speeds typically observed in quasars (10 c to 20 c). In 0716+714, younger components that were ejected more recently seem to move systematically slower than the older components. This and a systematic position angle variation of the inner (1 mas) portion of the VLBI jet suggests an at least partly geometric origin of the observed velocity variations. The observed rapid motion and the derived Lorentz factors are discussed with regard to the rapid Intra-Day Variability (IDV) and the γ-ray observations, from which very high Doppler factors are inferred.

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

Cited by 23 publications

References 28 publications

A multi-epoch VLBI survey of the kinematics of CJF sources

A multi-epoch VLBI survey of the kinematics of CJF sources

The kinematics in the pc-scale jets of AGN

Kinematic study of the blazar S5 0716+714

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