US/Mountain, 28 May - 2 June 2017
A large rotation of the polarization angle of the TeV Blazar W Comae
1 Instituto de Astronomía, Universidad Nacional Autónoma de México, AP 70-264, 04510 DF, Mexico
2 Instituto de Astronomía, Universidad Nacional Autónoma de México, AP 877, 22800, Ensenada BC, Mexico
Published online: 9 December 2013
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 Δt ∼ 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 11) was observed. This rotation corresponds to a large change of Δθ ∼ 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%.
© Owned by the authors, published by EDP Sciences, 2013
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