J/A+A/695/A260ivo://CDS.VizieR/J/A+A/695/A260doi:10.26093/cds/vizier/bc-nq/lcgaCDSLivingston J.D.Nikonov A.S.Dzib S.A.Debbrecht L.C.Kovalev Y.Y.,Lisakov M.M.MacDonald N.R.Paraschos G.F.Roder J.Wielgus M.2026-07-03T06:36:42Z2025-03-25T08:14:39ZCDS support team

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

cds-question@unistra.fractive-galactic-nucleimagnetic-fieldspolarimetryActive galactic nuclei (AGN) are some of the most luminous and extreme environments in the Universe. The central engines of AGN are believed to be super-massive black-holes (SMBHs) are fed by accretion discs threaded by magnetic fields within a dense magneto-ionic medium. We report our findings from polarimetric very-long-baseline interferometry (VLBI) observations of quasar NRAO 150 taken in October 2022 using a combined network of the Very Long Baseline Array (VLBA) and Effelsberg 100-m Radio Telescope. These observations comprise the first co-temporal multi-frequency polarimetric VLBI observations of NRAO 150 at frequencies above 15GHz. We used the new VLBI polarization calibration procedure, GPCAL, with polarization observations of frequencies of 12GHz, 15GHz, 24GHz, and 43GHz of NRAO 150. From these observations, we were able to measure the Faraday rotation and use it to derive the intrinsic electric vector position angle (EVPA0) for the source. As a complementary measurement, we determined the behavior of polarization as a function of observed frequency. The polarization from NRAO 150 only comes from the core region, with a peak polarization intensity occurring at 24GHz. Across the core region of NRAO 150, we see clear gradients in Faraday rotation and EVPA0 values that are aligned with the direction of the jet curving around the core region. We find that for the majority of the polarized region the polarization fraction is greater at higher frequencies, with intrinsic polarization fractions in the core ~=3%. The Faraday rotation gradients and circular patterns in EVPA0 offer strong evidence to support the presence of a helical+toroidal magnetic field. Furthermore, the presence of low intrinsic polarization fractions indicate that the polarized emission and, hence, the helical+toroidal magnetic field, is present within the innermost jet.2025A&A...695A.260Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/695/A260CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/566/A26 : Jet models for the quasar NRAO150 (Molina+, 2014)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/695/A260https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/695/A260http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/695/A260https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/695/A260https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/695/A260http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/695/A260GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/695/A260/list (List of fits images)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/695/A260/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/695/A260/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/695/A260/list?GETtext/xml+votable180.050000true59.8739550.963930.005555555555555556Associated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/A+A/695/A2606/1782https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/695/A260?format=asciidefaultJ/A+A/695/A260/listList of fits imagesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension of center (J2000)degpos.eq.ra;meta.mainDEJ2000Declination of center (J2000)degpos.eq.dec;meta.mainNxNumber of pixels along X-axismeta.numberintNyNumber of pixels along Y-axismeta.numberintObs.dateObservation datestime.epoch;obsnullablesizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitscharAssocDataAssociated Data web pagemeta.ref.urlchar