Polarization angle swings in blazars: The case of 3C 279

DOI: 
10.1051/0004-6361/201527725
Publication date: 
01/05/2016
Main author: 
Kiehlmann, S.
IAA authors: 
Agudo, I.;Casadio, C.;Gómez, J. L.
Authors: 
Kiehlmann, S.;Savolainen, T.;Jorstad, S. G.;Sokolovsky, K. V.;Schinzel, F. K.;Marscher, A. P.;Larionov, V. M.;Agudo, I.;Akitaya, H.;Benítez, E.;Berdyugin, A.;Blinov, D. A.;Bochkarev, N. G.;Borman, G. A.;Burenkov, A. N.;Casadio, C.;Doroshenko, V. T.;Efimova, N. V.;Fukazawa, Y.;Gómez, J. L.;Grishina, T. S.;Hagen-Thorn, V. A.;Heidt, J.;Hiriart, D.;Itoh, R.;Joshi, M.;Kawabata, K. S.;Kimeridze, G. N.;Kopatskaya, E. N.;Korobtsev, I. V.;Krajci, T.;Kurtanidze, O. M.;Kurtanidze, S. O.;Larionova, E. G.;Larionova, L. V.;Lindfors, E.;López, J. M.;McHardy, I. M.;Molina, S. N.;Moritani, Y.;Morozova, D. A.;Nazarov, S. V.;Nikolashvili, M. G.;Nilsson, K.;Pulatova, N. G.;Reinthal, R.;Sadun, A.;Sasada, M.;Savchenko, S. S.;Sergeev, S. G.;Sigua, L. A.;Smith, P. S.;Sorcia, M.;Spiridonova, O. I.;Takaki, K.;Takalo, L. O.;Taylor, B.;Troitsky, I. S.;Uemura, M.;Ugolkova, L. S.;Ui, T.;Yoshida, M.;Zensus, J. A.;Zhdanova, V. E.
Journal: 
Astronomy and Astrophysics
Publication type: 
Article
Volume: 
590
Pages: 
A10
Abstract: 
Context. Over the past few years, on several occasions, large, continuous rotations of the electric vector position angle (EVPA) of linearly polarized optical emission from blazars have been reported. These events are often coincident with high energy γ-ray flares and they have attracted considerable attention, since they could allow us to probe the magnetic field structure in the γ-ray emitting region of the jet. The flat-spectrum radio quasar <ASTROBJ>3C 279</ASTROBJ> is one of the most prominent examples showing this behaviour. <BR /> Aims: Our goal is to study the observed EVPA rotations and to distinguish between a stochastic and a deterministic origin of the polarization variability. <BR /> Methods: We have combined multiple data sets of R-band photometry and optical polarimetry measurements of <ASTROBJ>3C 279</ASTROBJ>, yielding exceptionally well-sampled flux density and polarization curves that cover a period of 2008-2012. Several large EVPA rotations are identified in the data. We introduce a quantitative measure for the EVPA curve smoothness, which is then used to test a set of simple random walk polarization variability models against the data. <BR /> Results: <ASTROBJ>3C 279</ASTROBJ> shows different polarization variation characteristics during an optical low-flux state and a flaring state. The polarization variation during the flaring state, especially the smooth ~360° rotation of the EVPA in mid-2011, is not consistent with the tested stochastic processes. <BR /> Conclusions: We conclude that, during the two different optical flux states, two different processes govern polarization variation, which is possibly a stochastic process during the low-brightness state and a deterministic process during the flaring activity.The measured and processed optical polarization and R-band photometry data are only available at the CDS via anonymous ftp to <A href='http://cdsarc.u-strasbg.fr'>http://cdsarc.u-strasbg.fr</A> (ftp://130.79.128.5) or via <A href='http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/590/A10'>http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/590/A10</A>
Database: 
ADS
SCOPUS
SCOPUS
WOK
URL: 
https://ui.adsabs.harvard.edu/#abs/2016A&A...590A..10K/abstract
ADS Bibcode: 
2016A&A...590A..10K
Keywords: 
polarization;galaxies: active;galaxies: jets;quasars: individual: 3C 279