J/MNRAS/392/1181ivo://CDS.VizieR/J/MNRAS/392/1181doi:10.26093/cds/vizier.73921181CDSDai B.Z.Li X.H.Liu Z.M.Zhang B.K.Na W.W.Wu Y.F.Hao J.M.,Xiang Y.Jiang Z.J.Zhang L.2024-07-07T20:17:34Z2009-06-29T21:52:28ZCDS support team

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

cds-question@unistra.frbl-lacertae-objectsinfrared-photometryvisible-astronomybroad-band-photometryThe long baseline simultaneous multiband (BVRI) observations of blazar 3C 273 are presented. We have made 758 optical multiband observations with the Yunnan Astronomical Observatory (YAO) 103cm and Shanghai Astronomical Observatory (SHAO) 156cm from 2003 January to 2005 April. In our observational campaign, the average colour indices are B-V=0.21, V-R= 0.26 and R-I=0.31 . The mean magnitudes in B, V, R and I are 12.895, 12.698, 12.441 and 12.139, respectively. The source is in a steady state over observational campaign. The correlations between colour index and brightness are discussed. We find that the correlations of B-V versus B, V-R versus V and R-I versus R have significant negative correlation, while B-V versus V, V-R versus R and R-I versus I have positive correlation. These strong correlations imply that the spectrum becomes bluer (flatter) when the source becomes brighter, and redden (softer) when the source fades both in intraday and long-term variability. The spectral evolution trends of 3C 273 are consistent with those of BL Lac objects.2009MNRAS.392.1181Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/392/1181CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/392/1181https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/392/1181http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/392/1181https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/392/1181https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/392/1181http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/392/1181GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticalInfrareddefaultJ/MNRAS/392/1181/table3The observations in B,V,R,I bandsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMJDModified Julian datedtime.epochdoubleObsObservation datestime.epoch;obsnullablemagMagnitude in band "Band"magphot.magfloate_magrms uncertainty on magmagstat.error;phot.magfloatBand[BVRI] Magnitude photometric band (1)instr.bandpasscharTelTelescope used (SAO or YAO)instr.setupchar