V. M. Larionov, S. G. Jorstad, A. P. Marscher, D. A. Morozova, I. S. Troitsky, D. A. Blinov, E. N. Kopatskaya, E. G. Larionova
We present optical photopolarimetric observations of the BL Lac object S4
0954+658 obtained with the 70-cm telescope in Crimea, 40-cm telescope in
St.Petersburg, and 1.8-m Perkins telescope at Lowell Observatory (Flagstaff,
Az). After a faint state with a brightness level R ~17.6 mag registered in the
first half of January 2011, the optical brightness of the source started to
rise and reached ~14.8 mag during the middle of March, showing flare-like
behavior. The most spectacular case of intranight variability was observed
during the night of 2011 March 9, when the blazar brightened by ~0.7 mag within
~7 hours. During the rise of the flux the position angle of optical
polarization rotated smoothly over more than 200 degrees. S4 0954+658 is a
gamma-ray blazar with gamma-ray flux of (5{\pm}3)x10^{-10} phot/cm^2/s
according to the Fermi 11-month Catalog Extragalactic Sources. Our analysis of
contemporaneous Fermi LAT data does not show any sign of increased gamma-ray
activity above the detection threshold except for an elevated flux on 2011
March 5, JD2455626, coincident with the local optical maximum.
View original:
http://arxiv.org/abs/1110.5861
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