J/MNRAS/523/3615 MOJAVE XXI Polarization variability in AGN jets (Zobnina+ 2023)
MOJAVE. XXI.
Decade-long linear polarization variability in AGN jets at parsec scales.
Zobnina D.I., Aller H.D., Aller M.F., Homan D.C., Kovalev Y.Y.,
Lister M.L., Pashchenko I.N., Pushkarev A.B., Savolainen T.
<Mon. Not. R. Astron. Soc., 523, 3615-3628 (2023)>
=2023MNRAS.523.3615Z 2023MNRAS.523.3615Z (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, radio ; Active gal. nuclei ; Interferometry ; VLBI
Keywords: polarization - galaxies: active - BL Lacertae objects: general -
galaxies: jets - quasars: general - radio continuum: galaxies
Abstract:
Using stacking of images obtained at different epochs, we studied the
variability properties of linear polarization of active galactic
nucleus (AGN) jets on parsec-scales. Our sample is drawn from the
MOJAVE programme, and consists of 436 AGNs manifesting core-jet
morphology and having at least five VLBA observing epochs at 15 GHz
from 1996 January through 2019 August, with some additional archival
VLBA data reduced by us. We employed a stacking procedure and
constructed maps of (i) standard deviation of fractional polarization
and electric vector position angle (EVPA) over epochs as the measure
of variability and (ii) median polarization degree to quantify typical
values in time. The distributions of these values along and across the
jet were analysed for the whole sample for the first time. We found
that core EVPA variability is typically higher than that of the jet,
presumably due to component blending and outflow bends in the core.
The BL Lacertae object cores have lower EVPA variability, compared to
that of quasars, possibly due to lower Faraday rotation measure,
suggesting a stronger ordered magnetic field component. The EVPA
becomes more stable down the jet. Most of the sources showing this
trend have a time coverage of more than 12 yr and at least 15 epochs.
The possible cause could be the increase of stability in the magnetic
field direction, reflecting an increase in the fraction of the
magnetic field that is ordered. There are no significant
optical-class-dependent or spectral-class-dependent relations in the
EVPA variability properties in AGN jets.
Description:
table2.dat contains the name of the sources in the B1950 notation,
alias, optical class, SED peak class, redshift, reference for
redshift/optical class.
table4.dat contains the name of the sources in the B1950 notation,
date of first epoch of VLBA observations, time span between first and
last epochs, number of observing epochs, size of the restoring beam,
map peak in mean total intensity, noise level of mean total intensity
map, map peak in median linearly polarized intensity, median epoch noise
level of linearly polarized intensity.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 81 436 Source general characteristics
table4.dat 66 436 Observational and multi-epoch source properties
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See also:
J/AJ/137/3718 : 15GHz monitoring of AGN jets with VLBA (Lister+, 2009)
J/ApJS/171/376 : MOJAVE. III. VLA 1.4GHz images (Cooper+, 2007)
J/AJ/131/1262 : Circular polarization images at 15GHz of AGN jets
(Homan+, 2006)
J/AJ/130/1389 : Linear polarization of AGN jets at 15GHz (Lister+, 2005)
J/AJ/138/1874 : MOJAVE. VI. Kinematic analysis of blazar jets
(Lister+, 2009)
J/ApJ/706/1253 : MOJAVE VII. Blazar jet acceleration (Homan+, 2009)
J/AJ/144/105 : MOJAVE. VIII. Faraday rotation in AGN jets. (Hovatta+, 2012)
J/A+A/545/A113 : MOJAVE IX. Core shift effects (Pushkarev+, 2012)
J/AJ/146/120 : MOJAVE. X. Parsec-scale kinematics of AGNs (Lister+, 2013)
J/AJ/147/143 : MOJAVE. XI. Spectral distributions (Hovatta+, 2014)
J/ApJ/798/134 : MOJAVE. XII. Acceleration of blazar jets (Homan+, 2015)
J/AJ/152/12 : MOJAVE. XIII. New 15GHz observations on 1994-2013
(Lister+, 2016)
J/MNRAS/468/4992 : MOJAVE XIV. AGN jet shapes + opening angles
(Pushkarev+, 2017)
J/ApJS/234/12 : MOJAVE XV. VLBA 15GHz obs. of AGN jets 1996-2016
(Lister+, 2018)
J/ApJ/862/151 : MOJAVE. XVI: parsec-scale AGN jet cores at 15GHz
(Hodge+, 2018)
J/ApJ/874/43 : MOJAVE. XVII. Parsec-scale jet kinematics of AGNs
(Lister+, 2019)
J/MNRAS/520/6053 : MOJAVE. XX. Persistent polarization in AGN jets
(Pushkarev+ 2023)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- NameB1950 Source name (HHMM+DDd, B1950)
11- 30 A20 --- OName Other name
33 A1 --- OptClass Optical class
36- 38 A3 --- SEDClass SED peak class
41- 45 F5.3 --- z ? Redshift
52- 81 A30 --- Ref Reference for redshift / optical class
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Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- NameB1950 Source name (HHMM+DDd, B1950)
11- 20 A10 "date" Epoch Date of first epoch
23- 26 F4.1 yr tau Time range between first and last epochs
29- 31 I3 --- N Number of stacked epochs
34- 37 F4.2 mas b FWHM of circular restoring beam
39- 46 F8.2 mJy/beam Imean-peak Map peak in mean total intensity
49- 52 F4.2 mJy/beam Imean-rms Noise level of mean total intensity map
55- 60 F6.2 mJy/beam Pmed-peak ? Map peak in median linearly polarized
intensity
63- 66 F4.2 mJy/beam Pmed-rms ? Median epoch noise level of linearly
polarized intensity
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Acknowledgements:
Daria Zobnina, di.zobnina(at)gmail.com
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 & Lister 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
Homan et al. Paper XII 2015ApJ...798..134H 2015ApJ...798..134H, cat. J/ApJ/798/134
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
Homan et al. Paper XIX 2021ApJ...923...67H 2021ApJ...923...67H
Pushkarev et al. Paper XX 2023MNRAS.520.6053P 2023MNRAS.520.6053P, Cat. J/MNRAS/520/6053
(End) Daria Zobnina [ASC LPI, Russia], Patricia Vannier [CDS] 17-Jul-2023