2017A&A...602A..29B


Query : 2017A&A...602A..29B

2017A&A...602A..29B - Astronomy and Astrophysics, volume 602A, 29-29 (2017/6-1)

A swirling jet in the quasar 1308+326.

BRITZEN S., QIAN S.-J., STEFFEN W., KUN E., KAROUZOS M., GERGELY L., SCHMIDT J., ALLER M., ALLER H., KRAUSE M., FENDT C., BOTTCHER M., WITZEL A., ECKART A. and MOSER L.

Abstract (from CDS):

Context. Despite numerous and detailed studies of the jets of active galactic nuclei (AGN) on pc-scales, many questions are still debated. The physical nature of the jet components is one of the most prominent unsolved problems, as is the launching mechanism of jets in AGN. The quasar 1308+326 (z=0.997) allows us to study the overall properties of its jet in detail and to derive a more physical understanding of the nature and origin of jets in general. The long-term data provided by the Monitoring Of Jets in Active galactic nuclei with Very Long Baseline Array (VLBA) experiments (MOJAVE)** survey permit us to trace out the structural changes in 1308+326 that we present here. The long-lived jet features in this source can be followed for about two decades.
Aims. We investigate the very long baseline interferomety (VLBI) morphology and kinematics of the jet of 1308+326 to understand the physical nature of this jet and jets in general, the role of magnetic fields, and the causal connection between jet features and the launching process.
Methods. Fifty VLBA observations performed at 15GHz from the MOJAVE survey were re-modeled with Gaussian components and re-analyzed (the time covered: 20 Jan. 1995-25 Jan. 2014). The analysis was supplemented by multi-wavelength radio-data (UMRAO, at 4.8, 8.0, and 14.5GHz) in polarization and total intensity. We fit the apparent motion of the jet features with the help of a model of a precessing nozzle.
Results. The jet features seem to be emitted with varying viewing angles and launched into an ejection cone. Tracing the component paths yields evidence for rotational motion. Radio flux-density variability can be explained as a consequence of enhanced Doppler boosting corresponding to the motion of the jet relative to the line of sight. Based on the presented kinematics and other indicators, such as electric-vector polarization position-angle (EVPA) rotation, we conclude that the jet of 1308+326 has a helical structure, meaning that the components are moving along helical trajectories and the trajectories themselves are also experiencing a precessing motion. A model of a precessing nozzle was applied to the data and a subset of the observed jet feature paths can be modeled successfully within this model. The data till 2012 are consistent with a swing period of 16.9yr. We discuss several scenarios to explain the observed motion phenomena, including a binary black hole model. It seems unlikely that the accretion disk around the primary black hole, which is disturbed by the tidal forces of the secondary black hole, is able to launch a persistent axisymmetric jet.
Conclusions. We conclude that we are observing a rotating helix. In particular, the observed EVPA swings can be explained by a shock moving through a straight jet that is pervaded by a helical magnetic field. We compare our results for 1308+326 with other astrophysical scenarios where similar, wound-up filamentary structures are found. They are all related to accretion-driven processes. A helically moving or wound up object is often explained by filamentary features moving along magnetic field lines of magnetic flux tubes. It seems that a "component" comprises plasma tracing the magnetic field, which guides the motion of the radiating radio-band plasma. Further investigations and modeling are in preparation.

Abstract Copyright: © ESO, 2017

Journal keyword(s): quasars: general - techniques: interferometric - techniques: interferometric

VizieR on-line data: <Available at CDS (J/A+A/602/A29): list.dat images/*>

Simbad objects: 13

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Number of rows : 13
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 ESO 428-14 Sy2 07 16 31.2062162520 -29 19 28.882826364   13.28 13.52 11.61   ~ 246 4
2 QSO J0738+1742 BLL 07 38 07.39375312 +17 42 18.9981506   16.76 16.22 15.78   ~ 955 1
3 UGC 4305 IG 08 19 04.9864630512 +70 43 13.086910452 12.06 11.72 11.39 11.11   ~ 743 2
4 [SST2011] J081929.00+704219.3 ULX 08 19 28.99 +70 42 19.4           ~ 180 2
5 6C 095456+654857 BLL 09 58 47.2451872176 +65 33 54.819354600     17.0 15.75   ~ 667 1
6 M 106 Sy2 12 18 57.620 +47 18 13.39   9.14 8.41 8.11   ~ 2272 3
7 3C 279 Bla 12 56 11.16657958 -05 47 21.5251510   18.01 17.75 15.87   ~ 2922 2
8 7C 1308+3236 BLL 13 10 28.66385420 +32 20 43.7828340   15.61 15.24 17.91   ~ 813 1
9 GRB 110328A gB 16 44 49 +57 34.9           ~ 403 0
10 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 13430 0
11 NAME Sgr A* X 17 45 40.03599 -29 00 28.1699           ~ 4041 3
12 8C 1803+784 BLL 18 00 45.6838528560 +78 28 04.018028016   16.4 16.4 15.46   ~ 711 1
13 SS 433 HXB 19 11 49.5647697480 +04 58 57.827127648   16.3 13.0     A7Ib: 2052 4

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2023.01.27-21:37:56

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