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Description
The gamma-ray blazar OJ 287 was in a high activity state during 2015 December-2016 February. Coinciding with this high brightness state, we observed this source for photometry on 40 nights in R-band and for polarimetry on nine epochs in UBV RI bands. During the period of our observations, the source brightness varied from 13.20+/-0.04 mag to 14.98+/-0.04mag and the degree of polarization (P) fluctuated between 6.0%+/-0.3% and 28.3%+/-0.8% in R-band. Focusing on intranight optical variability (INOV), we find a duty cycle of about 71% using {chi}^2^-statistics, similar to that known for blazars. From INOV data, the shortest variability timescale is estimated to be 142+/-38min, yielding a lower limit of the observed Doppler factor {delta}_0_=1.17, the magnetic field strength B<=3.8G, and the size of the emitting region R_s_<2.28x10^14^cm. On internight timescales, a significant anticorrelation between R-band flux and P is found. The observed P at U-band is generally larger than that observed at longer-wavelength bands, suggesting a wavelength-dependent polarization. Using V-band photometric and polarimetric data from Steward Observatory obtained during our monitoring period, we find a varied correlation between P and V-band brightness. While an anticorrelation is sometimes seen between P and V-band magnitude, no correlation is seen at other times, thereby suggesting the presence of more than one short-lived shock component in the jet of OJ 287.
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