Variability and stability in optical blazar jets: the case of OJ287

Understand

OJ287 is a BL Lac object at redshift z=0.306 that has shown double-peaked bursts at regular intervals of ~12 yr during the last ~ 40 yr.

• Due to this behavior, it has been suggested that OJ287 might host a close supermassive binary black hole.
• We present optical photopolarimetric monitoring data from 2005-2009, during which the latest double-peaked outburst occurred.
• We find a stable component in the optical jet: the optical polarization core.