VLBA Observations of Radio Reference Frame Sources. II. Astrometric Suitability Based on Observed Structure

Fey, A. L.; Charlot, P.

doi:10.1086/313017

Cited by 172 publications

(171 citation statements)

References 8 publications

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“…At higher frequencies (2.3, 8.6 and 15 GHz), the hot-spot is not visible by the VLBA, but there is evidence for a jet component along the direction of the hot-spot (Fey & Charlot 1997;Lister & Homan 2005).…”

Section: J1512-0905mentioning

confidence: 93%

Observations of 44 extragalactic radio sources with the VLBA at 92 cm

Rampadarath¹,

Garrett²,

Polatidis³

2009

A&A

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Section: J1512-0905mentioning

confidence: 93%

Observations of 44 extragalactic radio sources with the VLBA at 92 cm

Rampadarath¹,

Garrett²,

Polatidis³

2009

A&A

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“…This is done using the projection of the baseline in the source direction (e.g. Fey & Charlot 1997;Charlot 1990), on to the (u, v) plane. A fitted slope over all frequencies finally yields the additional group delay due to source structure (as described in Shabala et al 2015).…”

Section: Source Modelsmentioning

confidence: 99%

“…Sovers, Fanselow & Jacobs 1998), a temporal change in the brightness distribution of a source might also result in an apparent motion of this source (Ma et al 1998). Fey & Charlot (1997) showed that the size of the source structure (as, for example, determined by the SI) correlates with both the ICRF position accuracy and also with the magnitude of observed time variations in the source coordinates. Schaap et al (2013) confirmed the relation between observed source position uncertainties and structure indices, and further could relate greater position stability to the astrophysical property of scintillation.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

On the estimation of a celestial reference frame in the presence of source structure

Plank

Shabala

McCallum

et al. 2015

Mon. Not. R. Astron. Soc.

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The spatial structure of sources making up the celestial reference frame (CRF) at radio frequencies is a systematic error source in very long baseline interferometry (VLBI) measurements. Using simulations, we investigate the effects of source structure on the CRF, determined by the actual observational programme of the International VLBI Service for Geodesy and Astrometry. This is done using the source structure simulator of the Vienna VLBI Software. Applying various mock two-component source models, systematic displacements of 10-80 μas in median source position offsets are found. These offsets are predominantly aligned with the direction of the jet. The simulations further show that slight changes in the source model can significantly change the estimated positions. We finally present a new parametrization of source positions in the analysis, namely along the jet direction and perpendicular to it, allowing us to significantly mitigate the effects of source structure on an estimated CRF.

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“…We have collected published VLBI data from the literature with observations dating back to the early 1980s (Roberts et al 1987, Gabuzda et al 1989, Gabuzda & Cawthorne 1996, Vicente et al 1996, Fey et al 1996, Tateyama et al 1996, 1999, Fey & Charlot 1997, Rantakyrö et al 1998, Gabuzda & Gomez 2001, Tateyama & Kingham 2004, Ojha et al 2004, Jorstad et al 2001, 2005, Piner et al 2007, D'Arcangelo et al 2009). In addition, we have analysed 79 epochs of 15 GHz VLBA observations from the MOJAVE database (Lister et al 2009a), resulting in altogether 196 epochs of VLBI observations.…”

Section: Vlbi Datamentioning

confidence: 99%

Jet-disk connection in OJ287

Valtonen¹,

Savolainen²,

Wiik³

2010

Proc. IAU

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Abstract.A model for OJ 287 consisting of two orbiting black holes has been constructed using optical light curve data. The model has successfully predicted the occurrence of sharp optical outbursts of OJ 287 for the past 15 years. Here we test if also the variations in the radio jet position angle can be explained within the framework of this same model, which has most of its parameters fixed by the timing of the optical flares. The model applied here has only three free parameters left, the (trivial) zero point of the jet position angle, the time lag between changes in the disk and jet orientations, and the zero point of the viewing angle. Despite its simplicity and the small number of free parameters, the model appears to be able to reproduce the main properties of the observed position angle variations during the past 30 years. The best fits are obtained when the time lag is either ∼ 4 or ∼ 14 years. However, the jet orientation seems to be unrelated to the direction of the spin of the primary black hole. This implies, assuming that the basic model is correct, that the mean orientation of the jet is determined by the orientation of the inner accretion disk, not by the spin axis of the black hole.

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VLBA Observations of Radio Reference Frame Sources. II. Astrometric Suitability Based on Observed Structure

Cited by 172 publications

References 8 publications

Observations of 44 extragalactic radio sources with the VLBA at 92 cm

Observations of 44 extragalactic radio sources with the VLBA at 92 cm

On the estimation of a celestial reference frame in the presence of source structure

Jet-disk connection in OJ287

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