Optical multi-color monitoring of OJ 287 from 2006 to 2012

• Published in: Research in astronomy and astrophysics Vol. 17; no. 8; pp. 57 - 68
• Main Authors: Guo, Qian, Xiong, Ding-Rong, Bai, Jin-Ming, Fan, Xu-Liang, Yi, Wei-Min
• Format: Journal Article
• Language: English
• Published: Beijing National Astronomical Observatories, CAS and IOP Publishing Ltd 01.08.2017; IOP Publishing
• Subjects: active; BL Lacertae objects; BL Lacertae objects: individual (OJ 287); galaxies; galaxies: active; galaxies: photometry; individual; Lacertae; Light curve; objects; OJ; photometry; Variability
• ISSN: 1674-4527; 2397-6209
• DOI: 10.1088/1674-4527/17/8/82

We present our optical multi-color monitoring of the BL Lac object OJ 287 from January 2006to December 2012 in the V, R and I bands. A relatively active state in OJ 287 has been found over allmonitored epochs, among which the variations of average magnitude in V/R/I bands were measuredwith △V = 1.956 mag, △R =2.067 mag and A1 =2.115 mag, respectively. No reliable intraday variabil-ity is detected, but possible variability is detected on 16 nights. Their relative variation amplitudes fallinto the range between 1% and 8%, with the majority between 2% and 4%. No time lags have been de-tected, but strong correlations exist among light curves in the three wavebands. The bluer-when-brightertrend is dominant over intraday timescales, which supports the shock-in-jet model. When combiningwith additional V/R band data obtained from SMARTS and the Steward Observatory, we also find abluer-when-brighter trend over a long-term timescale. Some possible periods of 513, 176, 36, 30, 26,17 and 14 d are found in all time-series data sets from 2006 to 2017. Possible explanations about theseperiods are given.