J/A+A/555/A134ivo://CDS.VizieR/J/A+A/555/A134doi:10.26093/cds/vizier.35550134CDSLiu B.-R.Liu X.Marchili N.Liu J.Mi L.-G.Krichbaum T.P.,Fuhrmann L.Zensus J.A.2017-06-26T11:50:42Z2013-07-12T08:43:01ZCDS support team

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

cds-question@unistra.frquasarsradio-continuum-emissionThe quasar 1156+295 (4C +29.45) is one of the targets in the Urumqi monitoring program which aimed to search for evidence of annual modulation in the timescales of Intra-Day Variable (IDV) sources. The IDV observations of 1156+295 were carried out nearly monthly from October 2007 to October 2009, with the Urumqi 25m radio telescope at 4.8GHz. The source has shown prominent IDV of total flux density in most observing sessions with variability timescales of 1 day at 4.8GHz. The estimated IDV timescales seem to follow an annual cycle, which can be fitted with an anisotropic interstellar scintillation (ISS) model, suggesting that a significant part of the flux density variations is due to ISS. The source underwent a dramatic flare in 2008. We studied the possible consequences of the flare on the IDV of 1156+295, by comparing the changes in its variability characteristics with the evolution of the 43 GHz VLBA core size of the source. The quasar 1156+295 shows evidence for an annual modulation of its IDV timescales at 4.8GHz, the ISS-induced IDV timescales and variability strength might be affected by the overall activity state of the source core. More frequent IDV and VLBI measurements are required to confirm the relation between the IDV appearance and the core-size evolution of the source.2013A&A...555A.134Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/555/A134CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/544/A34 : Bright AGN VLBI imaging study at 2 and 8GHz (Pushkarev+, 2012)J/AJ/142/108 : Radio variability of compact, flat-spectrum AGNs (Koay+, 2011)J/ApJ/737/45 : Variable 1.4GHz radio sources from NVSS & FIRST (Ofek+, 2011)J/MNRAS/418/2260 : VLBI observations of NRAO 530 at 22, 43 & 86GHz (Lu+, 2011)J/ApJS/175/314 : VSOP 5GHz AGN survey V. (Dodson+, 2008)J/AJ/135/1384 : R-band variability in 5 blazars (Gupta+, 2008)J/ApJ/616/110 : VSOP 5GHz AGN Survey. IV (Horiuchi+, 2004)J/ApJS/131/95 : VSOP 5 GHz continuum survey (Fomalont+, 2000)J/PASJ/52/997 : VSOP 5 GHz AGN Survey (Hirabayashi+, 2000)J/A+AS/139/545 : 1-22 GHz spectra survey (Kovalev+, 1999)J/A+AS/128/315 : BVRI photometry of blazars (Jia Guibin+ 1998)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/555/A134https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/555/A134http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/555/A134https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/555/A134https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/555/A134http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/555/A134GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tap3.180513520130092e-24 3.180513520130092e-24RadiodefaultJ/A+A/555/A134/table3All flux density obtained with the Urumqi 25m radio telescope at 4.8GHzrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMJDModified Julian Date of observationdtime.epochdoubleFluxCalibrated flux density at 4.8GHzJyphot.flux.density;em.radio.3-6GHzfloate_FluxFlux uncertaintyJystat.error;phot.fluxfloat