J/A+A/574/A125ivo://CDS.VizieR/J/A+A/574/A125doi:10.26093/cds/vizier.35740125CDSde Bruyn A.G.Macquart J.-P.2017-09-08T12:33:24Z2015-02-05T08:35:14ZCDS support team

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

cds-question@unistra.frquasarsradio-continuum-emissionpolarimetryWe examine the long-term evolution of the intra-hour variable quasar, J1819+3845, whose variations have been attributed to interstellar scintillation by extremely local turbulent plasma, located only 1-3pc from Earth. The variations in this source ceased some time between June 2006 and February 2007. The evolution of the source spectrum and the long-term lightcurve, and the persistent compactness of the source VLBI structure indicates that the cessation of rapid variability was associated with the passage of the scattering material out of the line of sight to the quasar. We present an analysis of the linear polarization variations and their relation to total intensity variations. The proper motion of polarized features in the quasar jet is found to be subluminal. Systematic time delays between Stokes I, Q and U, in combination with the structure of the source obtained from 8.4GHz VLBI data, confirm the estimate of the screen distance: 1-2pc, making the screen one of the nearest objects to the Solar System. We determine the physical properties of this scattering material. We examine the rotation measures of sources and the diffuse polarized emission in the surrounding region. We place a limit of 10rad/m^2^ on the RM change. The variability of sources near J1819+3845 is used to deduce that the screen must therefore be either very small (~100AU) or patchy.2015A&A...574A.125Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/574/A125CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/574/A125https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/574/A125http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/574/A125https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/574/A125https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/574/A125http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/574/A125GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapAssociated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/A+A/574/A125RadiodefaultJ/A+A/574/A125/10012003*Light curve flux data in Figure 8 for UT 2003-01-10recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHA[-91/91] Hour angle of the target in degrees (G1)degpos.eq.hafloatSIFlux density for Stokes I at 6cm (4.9GHz)mJyphys.polarization.stokesfloatSQFlux density for Stokes Q at 6cm (4.9GHz)mJyphys.polarization.stokesfloatSUFlux density for Stokes U at 6cm (4.9GHz)mJyphys.polarization.stokesfloatSVFlux density for Stokes V at 6cm (4.9GHz)mJyphys.polarization.stokesfloatJ/A+A/574/A125/26012002*Light curve flux data in Figure 10 for UT 2002-01-26recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHA[-91/91] Hour angle of the target in degrees (G1)degpos.eq.hafloatSI3.6Flux density for Stokes I at 3.6cm (8.5GHz)mJyphys.polarization.stokesfloatSQ3.6? Flux density for Stokes Q at 3.6cm (8.5GHz) (only for 14062005.dat) (1)mJyphys.polarization.stokesfloatnullableSI6? Flux density for Stokes I at 6cm (4.9GHz) (only for 26012002.dat)mJyphys.polarization.stokesfloatnullableJ/A+A/574/A125/14062005*Light curve flux data in Figure 11 for UT 2005-06-14recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHA[-91/91] Hour angle of the target in degrees (G1)degpos.eq.hafloatSI3.6Flux density for Stokes I at 3.6cm (8.5GHz)mJyphys.polarization.stokesfloatSQ3.6? Flux density for Stokes Q at 3.6cm (8.5GHz) (only for 14062005.dat) (1)mJyphys.polarization.stokesfloatnullableSI6? Flux density for Stokes I at 6cm (4.9GHz) (only for 26012002.dat)mJyphys.polarization.stokesfloatnullableJ/A+A/574/A125/26022006*Light curve flux data in Figure 7 for UT 2006-02-26recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHA[-91/91] Hour angle of the target in degrees (G1)degpos.eq.hafloatSIFlux density for Stokes I at 6cm (4.9GHz)mJyphys.polarization.stokesfloatSQFlux density for Stokes Q at 6cm (4.9GHz)mJyphys.polarization.stokesfloatSUFlux density for Stokes U at 6cm (4.9GHz)mJyphys.polarization.stokesfloatSVFlux density for Stokes V at 6cm (4.9GHz)mJyphys.polarization.stokesfloatJ/A+A/574/A125/21022004*Light curve flux data in Figure 8 for UT 2004-02-21recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHA[-91/91] Hour angle of the target in degrees (G1)degpos.eq.hafloatSIFlux density for Stokes I at 6cm (4.9GHz)mJyphys.polarization.stokesfloatSQFlux density for Stokes Q at 6cm (4.9GHz)mJyphys.polarization.stokesfloatSUFlux density for Stokes U at 6cm (4.9GHz)mJyphys.polarization.stokesfloatSVFlux density for Stokes V at 6cm (4.9GHz)mJyphys.polarization.stokesfloatJ/A+A/574/A125/12022005*Light curve flux data in Figure 8 for UT 2005-02-12recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHA[-91/91] Hour angle of the target in degrees (G1)degpos.eq.hafloatSIFlux density for Stokes I at 6cm (4.9GHz)mJyphys.polarization.stokesfloatSQFlux density for Stokes Q at 6cm (4.9GHz)mJyphys.polarization.stokesfloatSUFlux density for Stokes U at 6cm (4.9GHz)mJyphys.polarization.stokesfloatSVFlux density for Stokes V at 6cm (4.9GHz)mJyphys.polarization.stokesfloatJ/A+A/574/A125/14042002*Light curve flux data in Figure 1 for UT 2002-04-14recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHA[-91/91] Hour angle of the target in degrees (G1)degpos.eq.hafloatSI13Flux density for Stokes I at 13cm (2272MHz)mJyphys.polarization.stokesfloatSI6Flux density for Stokes I at 6cm (4900MHz)mJyphys.polarization.stokesfloatSI3Flux density for Stokes I at 3cm (8463MHz)mJyphys.polarization.stokesfloatJ/A+A/574/A125/22012006*Light curve flux data in Figure 8 for UT 2006-01-22recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHA[-91/91] Hour angle of the target in degrees (G1)degpos.eq.hafloatSIFlux density for Stokes I at 6cm (4.9GHz)mJyphys.polarization.stokesfloatSQFlux density for Stokes Q at 6cm (4.9GHz)mJyphys.polarization.stokesfloatSUFlux density for Stokes U at 6cm (4.9GHz)mJyphys.polarization.stokesfloatSVFlux density for Stokes V at 6cm (4.9GHz)mJyphys.polarization.stokesfloat