A large rotation of the polarization angle of the TeV Blazar W Comae

Erika Benítez, Marco Sorcia, David Hiriart, José L. Gómez
2013 EPJ Web of Conferences  
Optical R-band polarimetric variability observations of the TeV Blazar W Comae are presented. Data obtained from 2008 February to 2013 May (∼5.2 years) are analyzed. The source presented a maximum flux variability of ∼3 mJy. The minimum variability time scale displayed by the source during the monitored period is ∆t ∼ 3.3 d. A maximum linear polarisation degree value of P= (33.8 ± 1.6)% was observed in 2013 May 12. A rotation of the position angle from 78 • (2008 March 10) to 229 • (2008 July
more » ... 229 • (2008 July 11) was observed. This rotation corresponds to a large change of ∆θ ∼ 150 • in a period of 123 d or to a rotation of ∼1.2 • per day. After the high activity state observed in 2008, the position angle shows a preferential value of ∼ 56 • , with variations of ∼60-120 • . From the Stokes parameters we infer the existence of two optically-thin synchrotron components that contribute to the optical polarized flux. One of them is stable, with P∼11%.
doi:10.1051/epjconf/20136107010 fatcat:4fxncudpr5edzn2gmbkdhcou4u