J/ApJ/794/54ivo://CDS.VizieR/J/ApJ/794/54doi:10.26093/cds/vizier.17940054CDSSorcia M.Benitez E.Hiriart D.Lopez J.M.Cabrera J.I.Mujica R.2017-07-03T13:29:14Z2017-05-12T16:05:55ZCDS support team

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

cds-question@unistra.frbl-lacertae-objectsaccretionpolarimetryphotometryAn R-band photopolarimetric variability analysis of the TeV bright blazar W Comae between 2008 February 28 and 2013 May 17 is presented. The source showed a gradual tendency to decrease its mean flux level with a total change of 3 mJy. A maximum and minimum brightness states in the R band of 14.25+/-0.04 and 16.52+/-0.1 mag, respectively, were observed, corresponding to a maximum variation of {Delta}F=5.40 mJy. We estimated a minimum variability timescale of {Delta}t=3.3 days. A maximum polarization degree P=33.8%+/-1.6%, with a maximum variation of {Delta}P=33.2%, was found. One of our main results is the detection of a large rotation of the polarization angle from 78{deg} to 315{deg} ({Delta}{theta}~237{deg}) that coincides in time with the {gamma}-ray flare observed in 2008 June. This result indicates that both optical and {gamma}-ray emission regions could be co-spatial. During this flare, a correlation between the R-band flux and polarization degree was found with a correlation coefficient of r_F-p _=0.93+/-0.11. From the Stokes parameters, we infer the existence of two optically thin synchrotron components that contribute to the polarized flux. One of them is stable with a constant polarization degree of 11%. Assuming a shock-in jet model during the 2008 flare, we estimated a maximum Doppler factor {delta}_D_~27 and a minimum of {delta}_D_~16; a minimum viewing angle of the jet ~2.0{deg}; and a magnetic field B~0.12 G.2014ApJ...794...54Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/794/54CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+AS/116/403 : VRI photometry of stars in 12 BL Lac objects (Fiorucci+, 1996)J/A+AS/128/315 : BVRI photometry of blazars (Jia Guibin+ 1998)J/ApJ/833/77 : gamma-ray bright blazars optical polarization (Itoh+, 2016)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/794/54https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/794/54http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/794/54https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/794/54https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/794/54http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/794/54GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/ApJ/794/54/table1Polarization and Photometry in the R-Band for W ComaerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintCycleCycle numbermeta.id;meta.maincharDateDate of the observationtime.epochnullableJDJulian Date of the observation (JD -2450000.00)dtime.epochdoublepPolarization degree%phys.polarizationfloate_pUncertainty in p%stat.errorfloatthetaOrientation of electric vector position angledegphys.electField;pos.posAnginte_thetaUncertainty in thetadegstat.error;pos.posAngintRmagR band magnitudemagphot.mag;em.opt.Rfloate_RmagUncertainty in Rmagmagstat.error;phot.mag;em.opt.RfloatRFluxR band flux densitymJyphot.flux.density;em.opt.Rfloate_RFluxUncertainty in RFluxmJystat.errorfloat