J/AJ/157/95ivo://CDS.VizieR/J/AJ/157/95doi:10.26093/cds/vizier.51570095CDSGupta A.C.Gaur H.Wiita P.J.Pandey A.Kushwaha P.Hu S.M.,Kurtanidze O.M.Semkov E.Damljanovic G.Goyal A.Uemura M.Darriba A.,Chen XuVince O.Gu M.F.Zhang Z.Bachev R.Chanishvili R.Itoh R.,Kawabata M.Kurtanidze S.O.Nakaoka T.Nikolashvili M.G.Stawarz L.,Strigachev A.2019-07-24T13:40:23Z2019-06-07T06:47:35ZCDS support team

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

cds-question@unistra.frbl-lacertae-objectsinfrared-photometryvisible-astronomybroad-band-photometryWe report on a recent multiband optical photometric and polarimetric observational campaign of the blazar OJ 287 that was carried out during 2016 September-2017 December. We employed nine telescopes in Bulgaria, China, Georgia, Japan, Serbia, Spain, and the United States. We collected over 1800 photometric image frames in BVRI bands and over 100 polarimetric measurements over ~175 nights. In 11 nights with many quasi-simultaneous multiband (V, R, I) observations, we did not detect any genuine intraday variability in flux or color. On longer timescales, multiple flaring events were seen. Large changes in color with respect to time and in a color-magnitude diagram were seen, and while only a weak systematic variability trend was noticed in color with respect to time, the color-magnitude diagram shows a bluer-when-brighter trend. Large changes in the degree of polarization and substantial swings in the polarization angle were detected. The fractional Stokes parameters of the polarization showed a systematic trend with time in the beginning of these observations, followed by chaotic changes and then an apparently systematic variation at the end. These polarization changes coincide with the detection and duration of the source at very high energies as seen by VERITAS. The spectral index shows a systematic variation with time and V-band magnitude. We briefly discuss possible physical mechanisms that could explain the observed flux, color, polarization, and spectral variability.2019AJ....157...95Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/157/95CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+AS/116/403 : VRI photometry of stars in 12 BL Lac objectsJ/A+AS/129/569 : BVRI photometry of OJ 287 (Jia Guibin+ 1998)J/A+A/450/39 : BVRI photometry of 8 red blazars (Gu+, 2006)J/AJ/132/1256 : eim BATC photometry of OJ 287 (Wu+, 2006)J/MNRAS/385/823 : UBVRI light curves of OJ 287 (Zheng+, 2008)J/MNRAS/402/2087 : Optical polarization of OJ 287 in 2005-2009J/AJ/141/65 : BATC ceimo light curves of OJ 287 (Dai+, 2011)J/ApJ/764/5 : BR photometry of 2012 precursor flare in OJ287J/A+A/562/A79 : Variability of seven blazars in six bandsJ/A+A/597/A80 : GMVA 86GHz images of OJ 287 (Hodgson+, 2017)J/ApJ/835/275 : OJ 287 flux + polarization during 2016 outburstJ/A+A/610/A74 : OJ 287 far-infrared photometry (Kidger+, 2018)J/A+A/619/A88 : High cadence polarization monitoring of OJ287https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/157/95https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/157/95http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/157/95https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/157/95https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/157/95http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/157/95GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapInfraredOpticaldefaultJ/AJ/157/95/table1Observation log of optical photometric observations of the blazar OJ 287recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateDate of the observationtime.epochnullableTelTelescope code (1)meta.code;instr.telcharo_Bmag[0/8] Number of B band observationsmeta.numberinto_Vmag[0/72] Number of V band observationsmeta.numberinto_Rmag[0/74] Number of R band observationsmeta.numberinto_Imag[0/74] Number of I band observationsmeta.numberintJ/AJ/157/95/table3Results of intraday variability (IDV) observationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateDate of the observationtime.epochnullableBandBand or colorinstr.bandpasscharNobs[13/74] Number of observations in Bandmeta.numberintF1[0.01/3.92] The F_1_ value in the F-teststat.fit.paramfloatF2[0.15/2.76] The F_2_ value in the F-teststat.fit.paramfloatF[0.4/3.1] The F value in the F-teststat.fit.paramfloatFc(0.99)[1.73/4.16] The F_c_(0.99) value in the F-teststat.fit.paramfloatFc(0.999)[2.08/7] The F_c_(0.999) value in the F-teststat.fit.paramfloatchi2(1)[7.22/320.75] The {chi}^2^_1_ value in the {chi}^2^-teststat.valuefloatchi2(2)[5.25/16199.26] The {chi}^2^_2_ value in the {chi}^2^-teststat.valuedoublechi2(av)[6.23/8117.93] The {chi}^2^_av_ value in the {chi}^2^-teststat.valuefloatchi2(0.99)[26.22/104.01] The {chi}^2^_0.99_ value in the {chi}^2^-teststat.valuefloatchi2(0.999)[32.91/116.09] The {chi}^2^_0.999_ value in the {chi}^2^-teststat.valuefloatW1[0.00308/4.43] The W_1_ value in the Levene teststat.fit.paramdoublep1[0.0385/0.956] The p_1_ value in the Levene teststat.fit.paramdoubleW2[6.56e-05/19.9] The W_2_ value in the Levene teststat.fit.paramdoublep2[1.59e-05/0.994] The p_2_ value in the Levene teststat.fit.paramdoubleVarVariable flag (NV=Non-variable)meta.code;src.varchar