Polarimetric Observations of 15 Active Galactic Nuclei at High Frequencies: Jet Kinematics from Bimonthly Monitoring with the Very Long Baseline Array

Jorstad, S. G.; Marscher, A. P.; Lister, M. L.; Stirling, A. M.; Cawthorne, T. V.; Gear, Walter Kieran; Gómez, J. L.; Stevens, J. A.; Smith, Paul S.; Forster, J. R.; Robson, E. I.

doi:10.1086/444593

Cited by 676 publications

(1,037 citation statements)

References 67 publications

(105 reference statements)

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“…More recently, Cohen et al (2014Cohen et al ( , 2015 present an analysis of more than a decade of 15 GHz VLBA observations of BLLac from the MOJAVE monitoring program. These observations confirm the existence of a stationary component, labeled C7 by these authors, located at a mean distance from the core of 0.26 mas and at a position angle of −166°.6, in agreement with component A2 reported by Jorstad et al (2005). This is also corroborated by our 15 and 43 GHz observations (see Table 2 and Figures 2 and 3), in which components U2 and Q2 would correspond to previously identified components A2 and C7, and component Q1 to A1.…”

Section: Stationary Components In the Innermost 05 Mas Regionsupporting

confidence: 91%

“…Component M1 is identified in the last two epochs as a weak knot beyond 0.5 mas from the core. The estimated apparent speed for this new component is c 7.9 0.3  (1.76 ± 0.06 mas yr −1 ), in agreement with values previously found in BLLac (Jorstad et al 2005), giving an ejection date of 2013.89±0.05, or 2013 November 23 (±18 days), in coincidence with our RadioAstron observations within the errors.…”

Section: Evidence For Emission Upstream Of the Coresupporting

confidence: 91%

“…In particular, Jorstad et al (2005) report, through an analysis of a sequence of 17 bimonthly VLBA observations at 43 GHz, two stationary components, labeled A1 and A2, located at a mean distance from the core (position angle) of 0.10 and 0.29 mas ( 160 -and 159 -), respectively. These can be associated with components C2 and C3 in Mutel & Denn (2005), respectively, obtained from independent 43 GHz VLBA observations.…”

Section: Stationary Components In the Innermost 05 Mas Regionmentioning

confidence: 99%

“…The jet of BLLac is pointing at us with a viewing angle of ∼8°with bulk flow at a Lorentz factor of ∼7 (Jorstad et al 2005). Previous observations have revealed a multiwavelength outburst, from radio to γ-rays, triggered by the passing of a bright moving feature through a standing shock associated with the core of the jet (Marscher et al 2008).…”

Section: Introductionmentioning

confidence: 99%

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PROBING THE INNERMOST REGIONS OF AGN JETS AND THEIR MAGNETIC FIELDS WITH RADIOASTRON. I. IMAGING BL LACERTAE AT 21 μas RESOLUTION

Gómez

Lobanov

Bruni

et al. 2016

ApJ

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138

163

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We present the first polarimetric space very long baseline interferometry (VLBI) imaging observations at 22 GHz. BLLacertae was observed in 2013 November 10 with the RadioAstron space VLBI mission, including a ground array of 15 radio telescopes. The instrumental polarization of the space radio telescope is found to be less than 9%, demonstrating the polarimetric imaging capabilities of RadioAstron at 22 GHz. Ground-space fringes were obtained up to a projected baseline distance of 7.9Earth diameters in length, allowing us to image the jet in BLLacertae with a maximum angular resolution of 21 μas, the highest achieved to date. We find evidence for emission upstream of the radio core, which may correspond to a recollimation shock at about 40 μas from the jet apex, in a pattern that includes other recollimation shocks at approximately 100 and 250 μas from the jet apex. Polarized emission is detected in two components within the innermost 0.5 mas from the core, as well as in some knots 3 mas downstream. Faraday rotation analysis, obtained from combining RadioAstron 22 GHz and groundbased 15 and 43 GHz images, shows a gradient in rotation measure and Faraday-corrected polarization vector as a function of position angle with respect to the core, suggesting that the jet in BLLacertae is threaded by a helical magnetic field. The intrinsic de-boosted brightness temperature in the unresolved core exceeds 3 10 12 K, suggesting, at the very least, departure from equipartition of energy between the magnetic field and radiating particles.

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Section: Stationary Components In the Innermost 05 Mas Regionsupporting

confidence: 91%

Section: Evidence For Emission Upstream Of the Coresupporting

confidence: 91%

Section: Stationary Components In the Innermost 05 Mas Regionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

PROBING THE INNERMOST REGIONS OF AGN JETS AND THEIR MAGNETIC FIELDS WITH RADIOASTRON. I. IMAGING BL LACERTAE AT 21 μas RESOLUTION

Gómez

Lobanov

Bruni

et al. 2016

ApJ

Self Cite

138

163

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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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Observational Details: Radio

Bridle

Cohen

2012

Relativistic Jets From Active Galactic Nuclei

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Polarimetric Observations of 15 Active Galactic Nuclei at High Frequencies: Jet Kinematics from Bimonthly Monitoring with the Very Long Baseline Array

Cited by 676 publications

References 67 publications

PROBING THE INNERMOST REGIONS OF AGN JETS AND THEIR MAGNETIC FIELDS WITH RADIOASTRON. I. IMAGING BL LACERTAE AT 21 μas RESOLUTION

PROBING THE INNERMOST REGIONS OF AGN JETS AND THEIR MAGNETIC FIELDS WITH RADIOASTRON. I. IMAGING BL LACERTAE AT 21 μas RESOLUTION

Jet-disk connection in OJ287

Observational Details: Radio

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