SIMBAD references

We present a detailed analysis on photopolarimetric monitoring on OJ 287 (OHIO J 287) conducted at the Nordic Optical Telescope during January 1991. Large rapid variations were observed in flux, polarization and position angle; the largest being a 40% increase in the flux with a simultaneous 55 degree position angle rotation in five hours. Changes in the wavelength dependent polarization and position angle were observed in timescales of hours. Several different models have been considered in explaining the observations. The standard two-component model or the shock in the jet model cannot explain all the observed variations, although many of the observed effects can be explained using a two-component model. Models with relativistic beaming effects or changes in the accretion disk can be used to explain these observations.