Abstract
We present results of 4 years of VLBA monitoring along with°-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°-ray and optical light curves. The majority of °-ray flares have optical counterparts. 67% of the°-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°-ray and optical emission is located in the vicinity or downstream of the mm-wave VLBI core.
Highlights
Blazars display high variability at different timescales over a broad range of frequencies
We have examined VLBA images of the sources for both variability of the core and appearance of superluminal knots ejected during this period
We have found that a high level of the γ-ray activity in 5 out of the 6 blazars studied coincides with the appearance of a new superluminal knot and/or a flare in the millimeterwave core, as well as optical flares
Summary
Blazars display high variability at different timescales over a broad range of frequencies. Their extreme properties are thought to be the result of their relativistic jets pointing toward us. Blazars comprise only a few percent of the overall AGN population, they represent the most numerous class of objects identified with γ-ray sources. The origin of this high-energy radiation is still not clear, according to radio-interferometer observations γray bright blazars have the most relativistic jets [1, 2]. There are a number of studies that have revealed a connection between the γ-ray emission and jet properties There are a number of studies that have revealed a connection between the γ-ray emission and jet properties (e.g. [3,4,5])
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
