Intra-Night Variability of OJ 287 with Long-Term Multiband Optical Monitoring

Abstract

Abstract:We present long-term optical multi-band photometric monitoring of the blazar OJ 287 from 6 March 2010 to 3 April 2016, with high temporal resolution in the VRI-bands. The flux variations and colour-magnitude variations on long and short timescales were investigated to understand the emission mechanisms. In our observation, the major outbursts occurred in January 2016, as predicted by the binary pair of black holes model for OJ 287, with F var of 1.3∼2.1%, and variability amplitude (Amp) of 5.8∼9.0%. The intra-night variability (IDV) durations were from 18.5 to 51.3 min, and the minimal variability timescale was about 4.7 min. The colour-magnitude variation showed a weak positive correlation on the long timescale with Pearson's r = 0.450, while a negative correlation was found on intra-night timescales. We briefly discuss the possible physical mechanisms that are most likely to be responsible for the observed flux and colour-magnitude correlation variability.

Observational Implications of OJ 287’s Predicted 2022 Disk Impact in the Black Hole Binary Model

“…This is the time when the Roche lobe flare should have been observed. This IDV flare of 4.2 mJy is an order of magnitude bigger than the IDV flares usually seen in OJ287 and, if regarded as a continuation of the normal IDV distribution, would represent over 10σ deviation [57]. Thus, it is most likely that we witness a different process here.…”

Minute-scale Rapid Variability of Mrk 501 by Multi-band Photometric Monitoring from 2010 to 2017

“…The field of view is ∼7.3×7.3 arcmin 2 . The readout noise and gain were 2.29 electrons and 1.4 electrons/ADU, respectively, with 16 μs (readout time per pixel) (Dai et al 2015;Xiong et al 2016;Zeng et al 2017Zeng et al , 2018. YAO2.4 was equipped with a 2×2 K Y-Faint Object Spectrograph and Camera (YFOSC), developed by Copenhagen University, with a field of view ∼10× 10 arcmin 2 (Dai et al 2015;Zeng et al 2018).…”

“…The image reduction and analysis procedures, soft packages, and aperture radius selection were described in our previous work (Dai et al 2015;Zeng et al 2017Zeng et al , 2018. We used the two comparison stars, star "1" and star "4" listed in Table 2, to obtain magnitudes for Mrk501 (m 1 and m 4 ), respectively, and then calculated the average (m 1 + m 4 )/2 as the magnitude of Mrk501 for each CCD frame.…”

Photometric Monitoring of Blazar 3C 66A with the Yunnan University Astronomical Observatory 1 m Telescope

“…4 Aperture photometry radii of the source and comparison stars are performed with the same value in each frame, which is determined by the FWHM of the source. As in our previous work, we concentrate on an aperture radius of about 1.5 FWHM for our analysis, which always provides the best signal-to-noise ratio (S/N) (Zeng et al 2017(Zeng et al , 2018(Zeng et al , 2019. We used the three comparison stars, star "2," star "3" and star "5" listed in Table 1, to obtain magnitudes for 3C 66A, and then calculated the average and corresponding standard deviation as the magnitude of 3C 66A in each photometric observation.…”