J/AJ/144/105ivo://CDS.VizieR/J/AJ/144/105doi:10.26093/cds/vizier.51440105CDSHovatta T.Lister M.L.Aller M.F.Aller H.D.Homan D.C.Kovalev Yu.Y.,Pushkarev A.B.Savolainen T.2017-12-07T07:27:43Z2013-10-29T13:24:54ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.fractive-galactic-nucleibl-lacertae-objectsquasarspolarimetryradio-continuum-emissionredshiftedWe report observations of Faraday rotation measures for a sample of 191 extragalactic radio jets observed within the MOJAVE program. Multifrequency Very Long Baseline Array observations were carried out over 12 epochs in 2006 at four frequencies between 8 and 15GHz. We detect parsec-scale Faraday rotation measures in 149 sources and find the quasars to have larger rotation measures on average than BL Lac objects. The median core rotation measures are significantly higher than in the jet components. This is especially true for quasars where we detect a significant negative correlation between the magnitude of the rotation measure and the de-projected distance from the core. We perform detailed simulations of the observational errors of total intensity, polarization, and Faraday rotation, and concentrate on the errors of transverse Faraday rotation measure gradients in unresolved jets. Our simulations show that the finite image restoring beam size has a significant effect on the observed rotation measure gradients, and spurious gradients can occur due to noise in the data if the jet is less than two beams wide in polarization. We detect significant transverse rotation measure gradients in four sources (0923+392, 1226+023, 2230+114, and 2251+158). In 1226+023 the rotation measure is for the first time seen to change sign from positive to negative over the transverse cuts, which supports the presence of a helical magnetic field in the jet. In this source we also detect variations in the jet rotation measure over a timescale of three months, which are difficult to explain with external Faraday screens and suggest internal Faraday rotation. By comparing fractional polarization changes in jet components between the four frequency bands to depolarization models, we find that an external purely random Faraday screen viewed through only a few lines of sight can explain most of our polarization observations, but in some sources, such as 1226+023 and 2251+158, internal Faraday rotation is needed.2012AJ....144..105Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/144/105CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVII/258 : Quasars and Active Galactic Nuclei (13th Ed.) (Veron+ 2010)J/A+A/545/A113 : MOJAVE IX. Core shift effects (Pushkarev+, 2012)J/ApJ/722/L7 : Fermi/LAT detected MOJAVE AGNs (Pushkarev+, 2010)J/ApJ/710/764 : Extended radio emission in MOJAVE blazars (Kharb+, 2010)J/ApJ/702/1230 : Rotation measure image of the sky (Taylor+, 2009)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/ApJS/171/376 : MOJAVE. III. VLA 1.4GHz images (Cooper+, 2007)J/AJ/131/1262 : AGN jets circular polarization images at 15GHz (Homan+, 2006)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)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/144/105https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/144/105http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/144/105https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/144/105https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/144/105http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/144/105GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/144/105/table1 (Sources and their rotation measure properties)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/144/105/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/144/105/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/144/105/table1?GETtext/xml+votable180.050000true1.5578869-6.39314860.0055555555555555566/18 556 579 700 911 1085 1263 1450 1509 1546 1701 1702 2143 2214 2414 2631 2721 2836 3024 3096 3309 3675 3820 3886 4054 4572 4695 4770 4820 5353 5423 5693 5767 5848 6252 6507 6641 6751 6853 6948 6984 7389 7570 7896 7969 8031 8220 8299 8487 8717 9347 9442 9460 9612 9632 9633 9676 9723 10163 10249 10321 10422 10548 11430 11639 11715 12047 12241 12352 12580 12604 12619 13156 13230 13352 13496 13693 13927 14520 14737 14744 15023 15067 15286 15494 15936 16027 16059 16093 16184 16298 16301 17184 17351 17579 17857 18035 18037 18378 18506 18624 18661 18669 18718 19088 19101 19190 19271 19398 19567 19593 19831 20099 20224 20468 20935 21266 21358 21564 21758 21768 21935 21960 21968 21972 22363 22375 22396 22658 22917 22950 23099 23121 23127 23323 23416 23691 24084 24571 25016 25196 25255 25302 25630 25742 25864 26115 26131 26292 26303 26491 26614 26900 26966 27060 27310 27417 27423 27765 28083 28479 28492 29016 29570 29675 29714 31190 31391 31399 31430 31451 31559 31664 31894 32660 32764 36188 36785 40527 40730 40762 44247 44805 44908 45011 48595 48610 48798 48846 48965 49071https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/144/105?format=asciiOpticalRadiodefaultJ/AJ/144/105/table1Sources and their rotation measure propertiesSimbadNameSimbad column added by the CDSmeta.idchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSource IAU name (B1950.0)meta.id;meta.maincharprimarynRMNumber of observed rotation measures of the 15GHz model-fit components for this AGN (table3)phot.flux.density;em.radio.12-30GHzintnullableONameOther namemeta.idcharz? Redshiftsrc.redshiftdoublenullableO[QBGU] Optical classification (1)src.classcharbeta? Apparent speed in units of the speed of light {beta}=v/c (2)cphys.veloc;arith.difffloatnullableObs.dateDate of rotation measure observationtime.epochnullableGRMGalactic rotation measure correction (from Taylor et al. 2009, cat. J/ApJ/702/1230)rad.m**-2arith.factor;phys.polarization.rotMeasure;pos.galacticfloatmRM? Median rotation measure over sourcerad.m**-2phys.polarization.rotMeasure;stat.medianfloatnullablemRMc? Median rotation measure over core arearad.m**-2phys.polarization.rotMeasure;stat.medianfloatnullablemRMj? Median rotation measure over jetrad.m**-2phys.polarization.rotMeasure;stat.medianfloatnullablePapVDisplay the data from Paper V (Lister et al. 2009, Cat. J/AJ/137/3718) if anymeta.numberintnullableJ/AJ/144/105/table3Model-fit components at 15.3GHz and their RM valuesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSource IAU name (B1950.0)meta.id;meta.maincharm_Name[0/26] Component identification (0=core component)meta.code.multipintDateDate of rotation measure observationtime.epochnullablerComponent distance from the phase center of the mapmaspos.angDistancefloatPA[-180/180] Component position angle from the phase center of the mapdegpos.posAngfloatRMComponent rotation measurerad.m**-2phys.polarization.rotMeasureinte_RMUncertainty in RMrad.m**-2stat.errorintI[Y] Indicates whether a jet component is isolated (see Section 3.3 for more details)meta.code;src.morphchar