Multiwavelength Observations of 6 BL Lac Objects in 2008-2012
1 Astron. Inst., St.-Petersburg State Univ., Russia
2 Institute for Astrophysical Research, Boston University, MA, USA
3 University of Crete, Heraklion, Greece
4 Joint Institute for VLBI in Europe, Dwingeloo, Netherlands
5 Instituto de Astrofisíca de Andalucía, CSIC, Granada, Spain
6 Steward Observatory, University of Arizona, Tucson, AZ, USA
Published online: 9 December 2013
We present results of 4 years of VLBA monitoring along with γ-ray and optical R-band photometric observations of 6 BL Lac objects (3C 66A, S5 0716+71, PKS 0735+17, S4 0954+68, W Com, and OT 081). We have analyzed total intensity images obtained with the VLBA at 43 GHz and investigated the kinematic evolution of the parsec scale jets of the sources. For all sources we compare flux variations in the VLBI core and bright superluminal knots with γ-ray and optical light curves. The majority of γ-ray flares have optical counterparts. 67% of the γ-ray events are coincident with the appearance of new superluminal knots and/or flares in the millimeter-wave core. These results support the conclusion that for many flares in blazars the region of the γ-ray and optical emission is located in the vicinity or downstream of the mm-wave VLBI core.
© Owned by the authors, published by EDP Sciences, 2013
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.