J/ApJS/232/7ivo://CDS.VizieR/J/ApJS/232/7doi:10.26093/cds/vizier.22320007CDSFraija N.Benitez E.Hiriart D.Sorcia M.Lopez J.M.Mujica R.,Cabrera J.I.De Diego J.A.Rojas-Luis M.Salazar-Vazquez F.A.,Galvan-Gamez A.2017-11-13T13:10:03Z2017-10-19T08:13:07ZCDS support team

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

cds-question@unistra.frbl-lacertae-objectsinfrared-photometryvisible-astronomyphotometrypolarimetryThe results of 8yr R-band photopolarimetric data of blazar Mrk 421 collected from 2008 February to 2016 May are presented, along with extensive multiwavelength observations covering radio to TeV {gamma}-rays around the flares observed in 2008 May, 2010 March, and 2013 April. The most important results are found in 2013, when the source displayed in the R band a very high brightness state of 11.29+/-0.03mag (93.60+/-1.53mJy) on April 10 and a polarization degree of 11.00%+/-0.44% on May 13. The analysis of the optical data shows that the polarization variability is due to the superposition of two polarized components that might be produced in two distinct emitting regions. An intranight photopolarimetric variability study carried out over seven nights after the 2013 April maximum found flux and polarization variations on the nights of April 14, 15, 16, and 19. In addition, the flux shows a minimum variability timescale of {Delta}t=2.34+/-0.12hr, and the polarization degree presents variations of~1%-2% on a timescale of {Delta}t~minutes. Also, a detailed analysis of the intranight data shows a coherence length of the large-scale magnetic field of l_B_~0.3pc, which is the same order of magnitude as the distance traveled by the relativistic shocks. This result suggests that there is a connection between the intranight polarimetric variations and spatial changes of the magnetic field. Analysis of the complete R-band data along with the historical optical light curve found for this object shows that Mrk 421 varies with a period of 16.26+/-1.78yr.2017ApJS..232....7Fhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/232/7CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+AS/116/403 : VRI photometry of stars in 12 BL Lac objects (Fiorucci+, 1996)J/A+AS/132/305 : Extragal. radio sources at 22, 37 and 87GHz (Terasranta+ 1998)J/ApJ/672/40 : AO 0235+164 outburst in 2006 December (Hagen-Thorn+, 2008)J/ApJ/700/597 : FERMI LAT detected blazars (Abdo+, 2009)J/ApJS/194/29 : Observations of blazars at 15GHz (Richards+, 2011)J/ApJ/794/54 : Polarization and photometry for blazar W Comae (Sorcia+, 2014)J/A+A/576/A126 : The 2009 multiwavelength campaign on Mrk421 (Aleksic+, 2015)J/A+A/578/A22 : Mrk421 in March 2010 (Aleksic+, 2015)J/A+A/593/A91 : Mrk 421 multi-wavelength variability, 2007-2009 (Ahnen+, 2016)J/ApJS/222/6 : 4.5yr obs. of Mrk421 with ARGO-YBJ & Fermi (Bartoli+, 2016)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/232/7https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/232/7http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/232/7https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/232/7https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/232/7http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/232/7GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapInfraredOpticaldefaultJ/ApJS/232/7/table1R-band photopolarimetric data of Mrk 421 from February 2008 to May 2016recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMJDModified Julian Date of observation; JD-2400000.5dtime.epochdoublePol[0.3/11] Polarization degree%phys.polarizationfloate_Pol[0.1/0.5] Uncertainty in Pol%stat.errorfloatPAPosition angledegpos.posAng;phys.polarizationfloate_PA[0.8/9] Uncertainty in PAdegstat.errorfloatRmag[11.2/13.6] R band magnitudemagphot.mag;em.opt.Rfloate_Rmag[0.03/0.1] Uncertainty in Rmagmagstat.error;phot.mag;em.opt.RfloatRFlux[11/94] Optical Flux, R bandmJyphot.flux.density;em.opt.Rfloate_RFlux[0.8/4] Uncertainty in RFluxmJystat.errorfloat