J/ApJ/798/134 MOJAVE. XII. Acceleration of blazar jets (Homan+, 2015)
MOJAVE.
XII. Acceleration and collimation of blazar jets on parsec scales.
Homan D.C., Lister M.L., Kovalev Y.Y., Pushkarev A.B., Savolainen T.,
Kellermann K.I., Richards J.L., Ros E.
<Astrophys. J., 798, 134 (2015)>
=2015ApJ...798..134H 2015ApJ...798..134H
ADC_Keywords: Active gal. nuclei ; Radio continuum ; Surveys ; QSOs
Keywords: BL Lacertae objects: general; galaxies: active; galaxies: jets;
quasars: general; radio continuum: galaxies; surveys
Abstract:
We report on the acceleration properties of 329 features in 95 blazar
jets from the MOJAVE Very Long Baseline Array program. Nearly half the
features and three-quarters of the jets show significant changes in
speed and/or direction. In general, apparent speed changes are
distinctly larger than changes in direction, indicating that changes
in the Lorentz factors of jet features dominate the observed speed
changes rather than bends along the line of sight. Observed
accelerations tend to increase the speed of features near the jet
base, ≲10-20pc projected, and decrease their speed at longer
distances. The range of apparent speeds at a fixed distance in an
individual jet can span a factor of a few, indicating that shock
properties and geometry may influence the apparent motions; however,
we suggest that the broad trend of jet features increasing their speed
near the origin is due to an overall acceleration of the jet flow out
to deprojected distances of the order of 102pc, beyond which the
flow begins to decelerate or remains nearly constant in speed. We
estimate intrinsic rates of change of the Lorentz factors in the
galaxy frame of the order of ⋅Γ/Γ~=10-3 to
10-2/yr, which can lead to total Lorentz factor changes of a factor
of a few on the length scales observed here. Finally, we also find
evidence for jet collimation at projected distances of ≲10pc in the
form of the non-radial motion and bending accelerations that tend to
better align features with the inner jet.
Description:
In this paper, we analyze observed accelerations for the kinematic
results presented in Paper X (Lister et al., 2013, J/AJ/146/120). This
work extends the analysis developed in Paper VII (Homan et al., 2009,
J/ApJ/706/1253) by expanding our sample of high quality motions
suitable for detailed acceleration study from 203 features in 63 jets
to 329 features in 95 jets.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
blazars.dat 8 95 List of blazars (table added by CDS)
table1.dat 114 329 Jet features for acceleration and non-radial
motion analysis
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See also:
J/A+A/566/A26 : Jet models for the quasar NRAO150 (Molina+, 2014)
J/AJ/146/120 : MOJAVE. X. Parsec-scale kinematics of AGNs (Lister+, 2013)
J/ApJ/758/84 : Relativistic jets in the RRFID database (10yr) (Piner+, 2012)
J/AJ/144/105 : MOJAVE. VIII. Faraday rotation in AGN jets. (Hovatta+, 2012)
J/ApJ/706/1253 : MOJAVE VII. Blazar jet acceleration (Homan+, 2009)
J/AJ/138/1874 : MOJAVE. VI. Kinematic analysis of blazar jets (Lister+, 2009)
J/AJ/137/3718 : 15GHz monitoring of AGN jets with VLBA (Lister+, 2009)
J/A+A/484/119 : Multi-epoch VLBI survey of CJF sources (Britzen+, 2008)
J/AJ/133/2357 : Relativistic jets in the RRFID database (Piner+, 2007)
J/AJ/130/2473 : Fine-scale structure in 250 sources at 15GHz (Kovalev+, 2005)
J/AJ/130/1418 : AGN jet kinematics (Jorstad+, 2005)
J/AJ/130/1389 : Linear polarization of AGN jets at 15GHz (Lister+, 2005)
J/ApJ/609/539 : Kinematics of parsec-scale radio jets (Kellermann+, 2004)
http://www.cv.nrao.edu/MOJAVE/sourcepages : MOJAVE home page
Byte-by-byte Description of file: blazars.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- QSO Source identifier (HHMM+DDd; B1950)
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Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
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1- 8 A8 --- QSO Source identifier (HHMM+DDd; B1950)
10- 11 I2 --- Seq [1/48] Component identifier
13- 15 I3 --- N [10/115] Number of epochs
17- 21 F5.2 mas [0.1/27.2] Mean radial separation from core
(averaged over all epochs)
23- 28 F6.1 deg [-178/179] Mean structural position angle
(<θ>)
30- 35 F6.2 pc dProj [0.1/213] Mean projected radial distance dproj
37- 40 I4 uas/yr pm [18/2941] Angular proper motion (µ)
42- 44 I3 uas/yr e_pm Uncertainty in pm
46- 49 F4.1 --- beta [0.1/44] Apparent speed βobs=v/c
51- 53 F3.1 --- e_beta Uncertainty in beta
55- 60 F6.1 deg phi [-180/180] Proper motion position angle (φ)
62- 64 F3.1 deg e_phi Uncertainty in phi
66- 70 F5.1 deg Diff [0/180] Absolute difference between mean
structural and proper motion PA |θ-φ|
72- 74 F3.1 deg e_Diff Uncertainty in Diff
76- 79 I4 uas/yr2 dmu [-698/1705] Angular acceleration parallel to
the proper motion position angle (µ||)
81- 83 I3 uas/yr2 e_dmu Uncertainty in dmu
85- 88 I4 uas/yr2 dmup [-819/800] Angular acceleration perpendicular tp
the proper motion position angle (µ⊥)
90- 92 I3 uas/yr2 e_dmup Uncertainty in dmup
94- 98 F5.2 yr-1 etaPa [-1.5/1.9] Relative parallel acceleration
η|| (1)
100-103 F4.2 yr-1 e_etaPa Uncertainty in etaPa
105-109 F5.2 yr-1 etaPe [-0.7/1.1] Relative perpendicular acceleration
η⊥ (1)
111-114 F4.2 yr-1 e_etaPe Uncertainty in etaPe
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Note (1): relative accelerations defined in section 3:
η|| = (dβ||/dt)/βapp = (1+Z)(dµ||/dt)/µ
η⊥ = (dβ⊥/dt)/βapp = (1+Z)(dµ⊥/dt)/µ
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History:
From electronic version of the journal
References:
Lister et al. Paper I. 2005AJ....130.1389L 2005AJ....130.1389L Cat. J/AJ/130/1389
Homan et al. Paper II. 2006AJ....131.1262H 2006AJ....131.1262H Cat. J/AJ/131/1262
Cooper et al. Paper III. 2007ApJS..171..376C 2007ApJS..171..376C Cat. J/ApJS/171/376
Cara et al. Paper IV. 2008ApJ...674..111C 2008ApJ...674..111C
Lister et al. Paper V. 2009AJ....137.3718L 2009AJ....137.3718L Cat. J/AJ/137/3718
Lister et al. Paper VI. 2009AJ....138.1874L 2009AJ....138.1874L Cat. J/AJ/138/1874
Homan et al. Paper VII. 2009ApJ...706.1253H 2009ApJ...706.1253H Cat. J/ApJ/706/1253
Hovatta et al. Paper VIII. 2012AJ....144..105H 2012AJ....144..105H Cat. J/AJ/144/105
Pushkarev et al. Paper IX. 2012A&A...545A.113P 2012A&A...545A.113P Cat. J/A+A/545/A113
Lister et al. Paper X. 2013AJ....146..120L 2013AJ....146..120L Cat. J/AJ/146/120
Hovatta et al. Paper XI. 2014AJ....147..143H 2014AJ....147..143H Cat. J/AJ/147/143
Lister et al. Paper XIII. 2016AJ....152...12L 2016AJ....152...12L Cat. J/AJ/152/12
Pushkarev et al. Paper XIV. 2017MNRAS.468.4992P 2017MNRAS.468.4992P Cat. J/MNRAS/468/4992
Lister et al. Paper XV. 2018ApJS..234...12L 2018ApJS..234...12L Cat. J/ApJS/234/12
Hodge et al. Paper XVI. 2018ApJ...862..151H 2018ApJ...862..151H Cat. J/ApJ/862/151
Lister et al. Paper XVII. 2019ApJ...874...43L 2019ApJ...874...43L Cat. J/ApJ/874/43
Lister et al. Paper XVIII. 2021ApJ...923...30L 2021ApJ...923...30L Cat. J/ApJ/923/30
Homan et al. Paper XIX. 2021ApJ...923...67H 2021ApJ...923...67H Cat. J/ApJ/923/67
Pushkarev et al. Paper XX. 2023MNRAS.520.6053P 2023MNRAS.520.6053P
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 08-Jun-2015