A helically twisted relativistic jet: nonradial motions and accelerations in 3C345

1986 ◽  
Vol 64 (4) ◽  
pp. 484-487 ◽  
Author(s):  
Philip E. Hardee
Keyword(s):  
Radio Source ◽  
Position Angle ◽  
Dynamical Equations ◽  
Parallel Straight Line ◽  
Helical Twist ◽  
Nonlinear Motion ◽  
Straight Line ◽  
Relativistic Jet ◽  
Jet Structure ◽  
Apparent Acceleration

The radio source 3C 345 has a curved, inner-jet structure consisting of three components. Components C2 and C3 appear to be moving with βapp ~ 17 and 13, respectively, along approximately parallel straight-line trajectories with motion along a mean direction ~ −75°. Component C4 recently appeared at a position angle ~ −135° and has exhibited nonlinear motion and apparent acceleration from βapp ~ 4–10 over a period of about 2 years with motion along a mean direction < −75°. We show how the motions of C4 can be explained by a feature that is propagating with constant speed along a helically twisted jet in which the wavelength of the helix increases in proportion to the jet's radius. This form for a helical twist is predicted by the linearized fluid-dynamical equations, which can be used to describe the response of a light jet to helical distortion.

scholarly journals The obstructed jet in Mrk 231

2021 ◽  
Author(s):  
Ailing Wang ◽  
Tao An ◽  
Sumit Jaiswal ◽  
Prashanth Mohan ◽  
Yuchan Wang ◽  
...  
Keyword(s):  
Large Scale ◽  
Position Angle ◽  
Opening Angle ◽  
Luminous Infrared Galaxies ◽  
Multi Scale ◽  
Long Baseline ◽  
Relativistic Jet ◽  
Multi Phase ◽  
Jet Structure ◽  
Projected Distance

Abstract Mrk 231 is the closest radio-quiet quasar known and one of the most luminous infrared galaxies in the local Universe. It is characterised by the co-existence of a radio jet and powerful multi-phase multi-scale outflows, making it an ideal laboratory to study active galactic nucleus (AGN) feedback. We analyse the multi-epoch very long baseline interferometry data of Mrk 231 and estimate the jet head advance speed to be ≲ 0.013 c, suggesting a sub-relativistic jet flow. The jet position angle changes from −113○ in the inner parsec to −172○ at a projected distance of 25 parsec. The jet structure change might result from either a jet bending following the rotation of the circum-nuclear disc or the projection of a helical jet on the plane of the sky. In the large opening angle (∼60○) cone, the curved jet interacts with the interstellar medium and creates wide-aperture-angle shocks which subsequently dissipate a large portion of the jet power through radiation and contribute to powering the large-scale outflows. The low power and bent structure of the Mrk 231 jet, as well as extensive radiation dissipation, are consistent with the obstruction of the short-length jet by the host galaxy’s environment.

scholarly journals A very straight and collimated outflow in the core of OMC-1

1991 ◽  
Vol 147 ◽  
pp. 491-493
Author(s):  
J. Schmid-Burgk ◽  
R. Güsten ◽  
R. Mauersberger ◽  
A. Schulz ◽  
T. L. Wilson
Keyword(s):  
Large Scale ◽  
Position Angle ◽  
Full Length ◽  
Hii Region ◽  
The Core ◽  
Straight Line ◽  
Outflow System

We have recently discovered a large-scale (200″) outflow system in the core of OMC-1 (fig. 1), centered about 100″ South of IRc2 and extending over some 120″ (red lobe) resp. 60″ (blue) along a position angle of —31° (Schmid-Burgk et al. 1990). The blue lobe which might actually protrude into the HII region M42 is poorly defined in CO 2-1, but the red lobe reveals a number of remarkable properties which we summarize here:The outflow is very straight and smooth. Over the full length of 120″, the center of any cross scan deviates by not more than about 1″ from a straight line. This line passes to within 2″ the peak of the submm source FIR4 of OMC-1 (Mezger, Wink and Zylka 1990) and the mm continuum peak CS3 (Mundy et al. 1986); it also cuts across the red and blue SiO-outflow lobes recently discovered some 5-10″ to either side of FIR4 (Ziurys, Wilson and Mauersberger 1990). It thus seems that the “base” of our large-scale CO jet can be seen as well.

scholarly journals A Multi-Frequency VLBI Total Intensity and Polarization Study of the BL Lacertae Object 0716+714

1998 ◽  
Vol 164 ◽  
pp. 173-174
Author(s):  
Y. Y. Kovalev ◽  
D. C. Gabuzda ◽  
T. P. Krichbaum ◽  
W. Alef ◽  
A. Witzel
Keyword(s):  
Linear Polarization ◽  
Position Angle ◽  
Published Data ◽  
Apparent Velocity ◽  
Structural Position ◽  
Core Polarization ◽  
Bl Lacertae ◽  
Polarization Study ◽  
Intensity Image ◽  
Jet Structure

AbstractNew polarization-sensitive global VLBI and VLBA images of the BL Lacertae object 0716+714 at 6 cm (1991.4) and 3.6 cm/1.3 cm (1994.2) are presented. The source shows a compact, one-sided core–jet structure in structural position angle ~ 13°. The 3.6 cm total intensity image shows the jet beginning to curve toward the arcsecond-scale structure, which lies in position angle ~ −45°. Comparison with previously published data suggests that the apparent velocity of a 6 cm jet component is > 1.09 ± 0.15c, if the red shift of 0716+714 is z > 0.3. Linear polarization from the VLBI core was detected at all three frequencies; in addition, polarization from the innermost jet component was detected at 1.3 cm. This compact jet polarization appears to be quite high, ~ 50%, and to be aligned with the jet direction, which can be understood if it is a transverse shock. The VLBI core polarization at our earlier epoch was perpendicular to the VLBI jet direction, but had rotated to align with the jet direction by the later epoch, about a year later. This rotation may indicate the imminent birth of a new VLBI component (shock).

scholarly journals Inclination Estimates from Off-Axis GRB Afterglow Modelling

Universe ◽  
2021 ◽  
Vol 7 (9) ◽  
pp. 329
Author(s):  
Gavin P. Lamb ◽  
Joseph J. Fernández ◽  
Fergus Hayes ◽  
Albert K. H. Kong ◽  
En-Tzu Lin ◽  
...  
Keyword(s):  
Neutron Star ◽  
Cosmological Parameters ◽  
Hubble Constant ◽  
Lateral Spreading ◽  
Line Of Sight ◽  
Temporal Behaviour ◽  
Model Free ◽  
Relativistic Jet ◽  
Free Parameters ◽  
Jet Structure

For gravitational wave (GW) detected neutron star mergers, one of the leading candidates for electromagnetic (EM) counterparts is the afterglow from an ultra-relativistic jet. Where this afterglow is observed, it will likely be viewed off-axis, such as the afterglow following GW170817/GRB 170817A. The temporal behaviour of an off-axis observed GRB afterglow can be used to reveal the lateral jet structure, and statistical model fits can put constraints on the various model free-parameters. Amongst these parameters is the inclination of the system to the line of sight. Along with the GW detection, the afterglow modelling provides the best constraint on the inclination to the line-of-sight and can improve the estimates of cosmological parameters, for example, the Hubble constant, from GW-EM events. However, modelling of the afterglow depends on the assumed jet structure and—often overlooked—the effects of lateral spreading. Here we show how the inclusion of lateral spreading in the afterglow models can affect the estimated inclination of GW-EM events.

scholarly journals Probing the pc- and kpc-scale Environment of the Powerful Radio Galaxy Hercules A

2002 ◽  
Vol 19 (1) ◽  
pp. 69-72 ◽  
Author(s):  
Nectaria A. B. Gizani ◽  
M. A. Garrett ◽  
J. P. Leahy
Keyword(s):  
Radio Source ◽  
Radio Galaxy ◽  
Angular Size ◽  
Position Angle ◽  
Extragalactic Radio Source ◽  
X Ray ◽  
Central Value ◽  
Intracluster Gas ◽  
Extended Emission ◽  
Powerful Radio Galaxy

AbstractWe present the kpc-scale behaviour of the powerful extragalactic radio source Hercules A and the behaviour of the intracluster gas in which the radio source is situated. We have found that Hercules A exhibits a strong Laing-Garrington effect. The X-ray observations have revealed an extended X-ray emission elongated along the radio galaxy axis. The estimated temperature of the cluster is kT=2.45 keV and the central electron density is n○≃7.8×10−3 cm−3 which reveals a hot, dense environment in which Hercules A is situated. From the combined study of the radio and X-ray data we have estimated a central value of 3 ≲ B○(μG)≲9.We also present the most recent results from the analysis of the radio data on the pc-scale structure of the radio galaxy, observed at 18 cm by the EVN–MERLIN array. A faint but compact radio source, coincident with the optical centre of Hercules A, was detected by the EVN at 18 mas resolution. The total flux density of the EVN core is 14.6 mJy. Its angular size is 18×7 mas with a position angle of ≃139°. There is also evidence for extended emission in the NW–SE direction, most probably from the eastern pc-scale jet. If this is true then there is a misalignment between the direction of the pc-eastern and the aligned kpc-scale jets of ≃35°.

scholarly journals A very straight and collimated outflow in the core of OMC-1

1991 ◽  
Vol 147 ◽  
pp. 491-493
Author(s):  
J. Schmid-Burgk ◽  
R. Güsten ◽  
R. Mauersberger ◽  
A. Schulz ◽  
T. L. Wilson
Keyword(s):  
Large Scale ◽  
Position Angle ◽  
Full Length ◽  
Hii Region ◽  
The Core ◽  
Straight Line ◽  
Outflow System

We have recently discovered a large-scale (200″) outflow system in the core of OMC-1 (fig. 1), centered about 100″ South of IRc2 and extending over some 120″ (red lobe) resp. 60″ (blue) along a position angle of —31° (Schmid-Burgk et al. 1990). The blue lobe which might actually protrude into the HII region M42 is poorly defined in CO 2-1, but the red lobe reveals a number of remarkable properties which we summarize here:The outflow is very straight and smooth. Over the full length of 120″, the center of any cross scan deviates by not more than about 1″ from a straight line. This line passes to within 2″ the peak of the submm source FIR4 of OMC-1 (Mezger, Wink and Zylka 1990) and the mm continuum peak CS3 (Mundy et al. 1986); it also cuts across the red and blue SiO-outflow lobes recently discovered some 5-10″ to either side of FIR4 (Ziurys, Wilson and Mauersberger 1990). It thus seems that the “base” of our large-scale CO jet can be seen as well.

scholarly journals Hydrodynamical backflow in X-shaped radio galaxy PKS 2014−55

2020 ◽  
Vol 495 (1) ◽  
pp. 1271-1283 ◽  
Author(s):  
W D Cotton ◽  
K Thorat ◽  
J J Condon ◽  
B S Frank ◽  
G I G Józsa ◽  
...  
Keyword(s):  
Radio Source ◽  
Radio Galaxy ◽  
Angular Resolution ◽  
Position Angle ◽  
Host Galaxy ◽  
Field Orientation ◽  
Hot Gas ◽  
Bright Region ◽  
Projected Length ◽  
The Magnetic Field

ABSTRACT We present MeerKAT 1.28 GHz total-intensity, polarization, and spectral-index images covering the giant (projected length l ≈ 1.57 Mpc) X-shaped radio source PKS 2014−55 with an unprecedented combination of brightness sensitivity and angular resolution. They show the clear ‘double boomerang’ morphology of hydrodynamical backflows from the straight main jets deflected by the large and oblique hot-gas halo of the host galaxy PGC 064440. The magnetic field orientation in PKS 2014−55 follows the flow lines from the jets through the secondary wings. The radio source is embedded in faint ($T_\mathrm{b} \approx 0.5 \mathrm{\, K}$) cocoons having the uniform brightness temperature and sharp outer edges characteristic of subsonic expansion into the ambient intragroup medium. The position angle of the much smaller (l ∼ 25 kpc) restarted central source is within 5° of the main jets, ruling out models that invoke jet re-orientation or two independent jets. Compression and turbulence in the backflows probably produce the irregular and low polarization bright region behind the apex of each boomerang as well as several features in the flow with bright heads and dark tails.

Optical polarization position angle versus radio source axis in radio galaxies

Nature ◽  
1982 ◽  
Vol 299 (5884) ◽  
pp. 605-606 ◽  
Author(s):  
Robert R. J. Antonucci
Keyword(s):  
Radio Source ◽  
Position Angle ◽  
Radio Galaxies ◽  
Optical Polarization

Optimization Design for Crank Arc Guide Bar Gathering Mechanism of Crab Claw Type Loading Machine

2012 ◽  
Vol 229-231 ◽  
pp. 547-550
Author(s):  
Zhong Hua Luo ◽  
She Huan Li
Keyword(s):  
Optimization Design ◽  
Error Function ◽  
Position Angle ◽  
Design Model ◽  
Optimization Result ◽  
End Point ◽  
Straight Line ◽  
Comprehensive Study ◽  
Loading Machine

This paper conducts a comprehensive study on the optimization design for crank arc guide bar gathering mechanism of crab claw type loading machine. The optimization aim is to make reality locus of gathering claw end-point be as in-accordance as possible with ideal locus, and so on. Formulae are derived for displacement of gathering claw end-point and position angle of the gathering claw. An optimization design model is established for the crank arc guide bar gathering mechanism. The crank arc guide bar gathering mechanism is optimized of crab claw type loading machine with 2100 mm wide, and the optimization result is satisfactory. Compared to the optimized crank straight line guide bar gathering mechanism in literature [2], the locus error function of gathering claw end-point has been largely improved with a reduction of 25.8%.

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