This paper aims to study the color behavior of the BL Lac object OJ 287 during optical outburst. According to the revisit of the data from the OJ-94 monitoring project and the analysis the data obtained with the 60/90 cm Schmidt Telescope of NAOC, we found a bluer-when-brighter chromatism in this object. The amplitude of variation tends to decrease with the decrease of frequency. These results are consistent with the shock-in-jet model. We made some simulations and confirmed that both amplitude difference and time delay between variations at different wavelengths can result in the phenomenon of bluer-when-brighter. Our observations confirmed that OJ 287 underwent a double-peaked outburst after about 12 years from 1996, which provides further evidence for the binary black hole model in this object.
@article{arxiv.1011.4989,
title = {Color Behavior Of BL Lacertae Object OJ 287 During Optical Outburst},
author = {Yan Dai and Jianghua Wu and Zong-Hong Zhu and Xu Zhou and Jun Ma},
journal= {arXiv preprint arXiv:1011.4989},
year = {2015}
}