J/ApJS/229/21ivo://CDS.VizieR/J/ApJS/229/21doi:10.26093/cds/vizier.22290021CDSXiong D.Bai J.Zhang H.Fan J.Gu M.Yi T.Zhang X.2017-09-04T07:58:32Z2017-06-28T09:55:33ZCDS support team

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

cds-question@unistra.frquasarsinfrared-photometryvisible-astronomyphotometryWe have monitored the quasar 3C 273 in the optical V, R, and I bands from 2005 to 2016. Intraday variability (IDV) is detected on seven nights. The variability amplitudes on most of the nights are less than 10%, and on four nights, more than 20%. When considering the nights with time spans >4hr, the duty cycle (DC) is 14.17%. Over the 12yrs, the overall magnitude and color index variabilities are {Delta}I=0.67, {Delta}R=0.72, {Delta}V=0.68, and {Delta}(V-R)=0.25, respectively. The largest clear IDV has an amplitude of 42% over just 5.8 minutes, and the weakest detected IDV is 5.4% over 175 minutes. The BWB (bluer when brighter) chromatic trend is dominant for 3C 273 and appears at different flux levels on intraday timescales. The BWB trend exists for short-term timescales and intermediate-term timescales but different timescales have different correlations. There is no BWB trend for our whole time-series data sets. A significant anticorrelation between the BWB trend and length of timescales is found. Combining with V-band data from previous works, we find a possible quasi-periodicity of P=3918+/-1112 days. The possible explanations for the observed variability, BWB chromatic trend, and periodicity are discussed.2017ApJS..229...21Xhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/229/21CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/601/A35 : High-fidelity VLA imaging of 3C273 (Perley+, 2017)J/A+A/576/A122 : 3C 273 high energy spectrum (Esposito+, 2015)J/ApJS/213/26 : Optical light curves of PHL1811 and 3C273 (Fan+, 2014)J/MNRAS/435/1300 : Intranight optical variability of AGN (Goyal+, 2013)J/MNRAS/392/1181 : BV(RI)c photometry of 3C 273 (Dai+, 2009)J/AJ/134/799 : Multiwaveband polarimetry of 15 AGN (Jorstad+, 2007)J/A+A/450/39 : BVRI photometry of 8 red blazars (Gu+, 2006)J/ApJ/522/846 : Optical monitoring of GeV loud blazars (Xie+, 1999)J/A+AS/132/83 : BVRI photometry of 7 BL Lac objects (Bai+ 1998)http://isdc.unige.ch/3c273/ : 3C 273's databasehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/229/21https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/229/21http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/229/21https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/229/21https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/229/21http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/229/21GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapInfraredOpticaldefaultJ/ApJS/229/21/table2Data of I BandrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateUT date of the observationtime.epoch;obsnullableMJDModified Julian Date of observationdtime.epochdoubleImag[11.9/12.6] Apparent I band magnitudemagphot.mag;em.opt.Ifloate_Imag[0.002/0.06] The rms error in Imagmagstat.error;phot.mag;em.opt.IfloatJ/ApJS/229/21/table3Data of R BandrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateUT date of the observationtime.epoch;obsnullableMJDModified Julian Date of observationdtime.epochdoubleRmag[12.3/13.1] Apparent R band magnitudemagphot.mag;em.opt.Rfloate_Rmag[0.001/0.06] The rms error in Rmagmagstat.error;phot.mag;em.opt.RfloatJ/ApJS/229/21/table4Data of V BandrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateUT date of the observationtime.epoch;obsnullableMJDModified Julian Date of observationdtime.epochdoubleVmag[12.4/13.1] Apparent V band magnitudemagphot.mag;em.opt.Vfloate_Vmag[0.001/0.05] The rms error in Vmagmagstat.error;phot.mag;em.opt.Vfloat