Multi-wavelength Photometric and Polarimetric Observations of the Outburst of 3C 454.3 in Dec. 2009

In December 2009, the bright blazar, 3C 454.3 exhibited a strong outburst in the optical, X-ray and gamma-ray regions. We performed photometric and polarimetric monitoring of this outburst in the optical and near-infrared bands with TRISPEC and HOWPol attached to the Kanata telescope. We also observed this outburst in the infrared band with AKARI, and the radio band with the 32-m radio telescope of Yamaguchi University. The object was in an active state from JD 2455055 to 2455159. It was 1.3 mag brighter than its quiescent state before JD 2455055 in the optical band. After the end of the active state in JD 2455159, a prominent outburst was observed in all wavelengths. The outburst continued for two months. Our optical and near-infrared polarimetric observations revealed that the position angle of the polarization (PA) apparently rotated clockwise by 240 degrees within 11 d in the active state (JD 2455063—2455074), and after this rotation, PA remained almost constant during our monitoring. In the outburst state, PA smoothly rotated counterclockwise by 350 degrees within 35 d (JD 2455157—2455192). Thus, we detected two distinct rotation events of polarization vector in opposite directions. We discuss these two events compared with the past rotation events observed in 2005, 2007 and 2008.This work was partly supported by a Grand-in-Aid from the Ministry of Education, Culture, Sports, Science, and Technology of Japan (22540252,). This research has made use of data from the University of Michigan Radio Astronomy Observatory which has been supported by the University of Michigan and by a series of grants from the National Science Foundation, most recently AST-0607523. The Submillimeter Array is a joint project between the Smithsonian Astrophysical Observatory and the Academia Sinica Institute of Astronomy and Astrophysics and is funded by the Smithsonian Institution and the Academia Sinica. M. Sasada and M. Yamanaka have been supported by the JSPS Research Fellowship for Young Scientists