J/AJ/132/1256ivo://CDS.VizieR/J/AJ/132/1256doi:10.26093/cds/vizier.51321256CDSWu J.Zhou X.Wu X.-B.Liu F.-K.Peng B.Ma J.Wu Z.Jiang Z.,Chen J.2017-07-05T07:00:03Z2008-06-11T16:03:57ZCDS support team

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

cds-question@unistra.frbl-lacertae-objectsphotometryWe present the results of our optical monitoring of the BL Lacertae object OJ 287 during the first half of 2005. The source did not show large-amplitude variations during this period and was in a relatively quiescent state. A possible period of 40 days was derived from its light curves in three BATC wave bands. A bluer-when-brighter chromatism was discovered, which is different from the extremely stable color during the outburst in 1994-1996. The different color behaviors imply different variation mechanisms in the two states. We then revisited the optical data on OJ 287 from the OJ-94 project and also found a probable period of 40 days in its optical variability during the late 1994 outburst. The results suggest that two components contribute to the variability of OJ 287 during its outburst state. The first component is the normal blazar variation. This component has an amplitude similar to that of the quiescent state and also may share a similar periodicity. The second component can be taken as a "low-frequency modulation" to the first component. It may be induced by the interaction of the assumed binary black holes in the center of this object. The 40 day period may be related to the helical structure of the magnetic field at the base of the jet or to the orbital motion close to the central primary black hole.2006AJ....132.1256Whttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/132/1256CatalogResearchIsServedByTAP VizieR generic servicerelated-toII/262 : BATC Data Release One - BATC DR1 (Zhou+ 1995-2005)J/A+AS/136/455 : BVRI photometry of 3 BL Lac objects (Bai+, 1999)J/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)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/132/1256https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/132/1256http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/132/1256https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/132/1256https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/132/1256http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/132/1256GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tap4.932729789091509e-19 5.256786987571587e-19OpticaldefaultJ/AJ/132/1256/oj287Observational log and results in the BATC e, i and m bandsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintObs.DateUT date of the Observation (1)time.epochnullableObs.TimeUT time of the Observation (1)time.epochnullableJDJulian Date of the Observation (1)dtime.epochdoubleExpExposure timestime.duration;obs.exposureintBand[eim] BATC band (2)instr.bandpasscharmagBATC band magnitudemagphot.magfloate_magError in magmagstat.error;phot.magfloat