OJ 287 flux & polarization during 2016 outburst

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.