Kinematics of the parsec-scale radio jet in 3C 48

An, Tao; Hong, Xiaoyu; Hardcastle, M. J.; Worrall, D. M.; Venturi, T.; Pearson, T. J.; Shen, Zhi-Qiang; Zhao, Wei; Feng, Wenxia

doi:10.1111/j.1365-2966.2009.15899.x

Cited by 38 publications

(22 citation statements)

References 49 publications

(88 reference statements)

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“…The jet may interact with the BLR and/or NLR clouds to generate stationary shocks. Abrupt changes in the jet direction and violent jet-ISM interactions have been observed in some compact-steep-spectrum sources such as 3C 48 (An et al 2010) and 4C 41.17 (Gurvits et al 1997). In addition, the intrinsically small jet bending in the inner 2 mas might be enhanced by projection effects.…”

Section: Precessing Jetmentioning

confidence: 99%

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Radio structure of the blazar 1156 + 295 with sub-pc resolution

Zhao

Hong

et al. 2011

A&A

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Aims. 1156+295 is a flat-spectrum quasar that is loud at both radio and γ-ray wavelengths. Previous observations of the source revealed a radio morphology on pc to kpc scales consistent with a helical jet model. We carried out VLBA observations at centimeter and millimeter wavelengths to study the structure of the innermost jet and understand the relation between the helical structure and astrophysical processes in the central engine. Results. A core-jet structure with six jet components is identified in 1156+295. Three jet components are detected for the first time. The apparent transverse velocities of the six jet components derived from proper motion measurements range between 3.6 c and 11.6 c, suggesting that highly relativistic jet plasma moves in the direction close to the line of sight. The overall jet has an oscillating morphology with multiple curvatures on pc scales, which might be indicative of a helical pattern. Models of a helical jet are discussed in the context of both Kelvin-Helmholtz (K-H) instability and jet precession. The K-H instability model is in closer agreement with the observed data. Conclusions. The overall radio structure on scales from sub-pc to kpc appears to be fitted with a hydrodynamic model in the fundamental helical mode of Kelvin-Helmholtz (K-H) instability. This helical mode with an initial characteristic wavelength of λ 0 = 0.2 pc is excited at the base of the jet on the scale of 0.005 pc (or 10 3 R s , the typical size of the broad line region of a supermassive black hole of 4.3 × 10 8 M ). A precessing jet model can also fit the observed jet structure on scales of between 10 pc and 300 pc. However, with the precessing jet model, additional astrophysical processes may be required to explain the bendings of the inner jet structure (1 to 10 pc) and re-collimation of the large-scale jet outflow (>300 pc).

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Section: Precessing Jetmentioning

confidence: 99%

“…Stirling et al 2003). On the basis of the assumption that the jet components are ejected from a precessing jet nozzle and move along ballistic paths, we fit the bright knots observed in the jet with a simple precessing model (Hjellming & Johston 1981;Baryshev 1983;An et al 2010).…”

Section: Precessing Jetmentioning

confidence: 99%

Radio structure of the blazar 1156 + 295 with sub-pc resolution

Zhao

Hong

et al. 2011

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“…Liu et al 2006;An et al 2013b) or the development of instabilities such as the Kelvin-Helmholtz instability (e.g. An et al 2010;Zhao et al 2011;Wang et al 2014, and references therein). The Keplerian timescale P for a spinning black hole (Kerr space-time outside the black hole) with dimensionless spin parameter a is given by…”

Section: Model Application and Discussionmentioning

confidence: 99%

Parsec-scale jet properties of the quasar PG 1302−102

Mohan¹,

An²,

Frey³

et al. 2016

Mon. Not. R. Astron. Soc.

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The quasar PG 1302−102 is believed to harbour a supermassive binary black hole (SMBBH) system. Using the available 15 GHz and 2 − 8 GHz, multi-epoch Very Long Baseline Array data, we constrain the pc-scale jet properties based on the inferred mean proper motion, including a bulk Lorentz factor 5.1 ± 0.8, jet inclination angle 11.• 4 ± 1.• 7, projected position angle = 31.• 8, intrinsic half opening angle 0.• 9 ± 0.• 1 and a mean 2 − 8 GHz spectral index of 0.31. A general relativistic helical jet model is presented and applied to predict quasi-periodic oscillations of ∼ 10 days, power law power spectrum shape and a contribution of up to ∼ 53 percent to the observed variable core flux density. The model is used to make a case for high resolution, moderately sampled, long duration radio interferometric observations to reveal signatures due to helical knots and distinguish them from those due to SMBBH orbital activity including a phase difference ∼ π and an amplitude ratio (helical light curve amplitude/SMBBH light curve amplitude) of 0.2 − 3.3. The prescription can be used to identify helical kinematic signatures from quasars, providing possible candidates for further studies with polarization measurements. It can also be used to infer promising SMBBH candidates for the study of gravitational waves if there are systematic deviations from helical signatures.

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“…If a significant fraction of the jet momentum flux is dissipated, the jet cannot sustain the supersonic laminar flow and forms a stagnating standing shock (i.e., the location of the hotspot) and becomes flaring and diffused beyond that point. Such a flared jet is found in the CSS quasar 3C 48, which has a compact and bright hotspot about 300 parsec from the central AGN (Wilkinson et al 1991;Worrall et al 2004;Feng et al 2005;An et al 2010). The decrease of jet power can happen in any stage of the radio source evolution when the nuclear activity is reduced or terminated, or the jet experiences significant loss of kinetic energy because of jet-ISM interactions (An & Baan 2012).…”

Section: Sideways Motion and Frustrated Jetsmentioning

confidence: 99%

Kinematics of the compact symmetric object OQ 208 revisited

Baan

et al. 2013

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Aims. A long-timeline kinematic study of the archetypal compact symmetric object (CSO) OQ 208 sheds light on the physical properties of the most compact radio sources. Methods. Archival data from the Very Long Baseline Array (VLBA) at 15 GHz over a time span of 13.6 yr were used to investigate the kinematics of the radio source. The flux density monitoring data obtained at the Michigan 26-m radio telescope were also used as supplementary information for analyzing the geometry of the radio structure. Results. At 2.3-GHz, the radio emission is dominated by two mini-lobes separated by ∼10 pc in a northeast-southwest (NE-SW) direction. At 8.4 and 15 GHz, each lobe is further resolved into two subcomponents, which are identified as hotspots. A knotty jet is linked with the NE hotspot and traces back toward the geometric center. The core is too weak to be detected. Significant flux density variation is found in the primary hotspots with a maximum level of 62% (NE1) and 19% (SW1). The flare epoch of NE1 is earlier than that of SW1 by approximately 5.00 yr, suggesting that the northeast lobe is advancing and the southwest lobe is receding. This light travel difference indicates a radial distance difference between the two hotspots of 1.53 pc, which indicates an inclination angle of about 80.8 degrees between the radio jet and the line of sight. The angular separation rate between NE1 and SW1 is 0.027 mas yr −1 , corresponding to a projected speed of 0.133 c. The inner jet knot (J1) moves at 0.047 mas yr −1 (or 0.230 c), about 3.5 times the hotspot advancing speed. Conclusions. The large viewing angle and the modest jet speed suggest a mildly relativistic jet. The jet axis is close to the plane of the sky. The separation rate and the distance between the two primary hotspots result in a kinematic age of 255 ± 17 yr, confirming that OQ 208 is indeed a young radio source. In addition to the hotspot advancing motions, sideways motions provide evidence that the lobes are obstructed by the external interstellar medium.

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Kinematics of the parsec-scale radio jet in 3C 48

Cited by 38 publications

References 49 publications

Radio structure of the blazar 1156 + 295 with sub-pc resolution

Radio structure of the blazar 1156 + 295 with sub-pc resolution

Parsec-scale jet properties of the quasar PG 1302−102

Kinematics of the compact symmetric object OQ 208 revisited

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