Kutkin, Alexander

A detailed study of the coreshift effect in the blazar 3C454.3.

Author list: A. M. Kutkin, K. V. Sokolovsky, M. M. Lisakov, P. A. Voytsik

We present a detailed study of the opacity-driven shift in the apparent parsec-scale radio core position (the ``coreshift effect``) in the blazar 3C454.3 during its 2008 flare. The effect is investigated using two independent techniques: cross-correlation analysis of single-dish 4.8-37 GHz radio light curves and 4.6-43 GHz VLBI data analysis. The VLBI analysis included uv-plane modeling of the source structure and image-plane cross-correlation to determine alignment between images at different frequencies. Both lightcurve and VLBI data analysis techniques provide consistent results. We estimate the magnetic field strength in the 43 GHz core as of B~0.07 G. Our analysis of time lags and core positions provide the jet velocity estimate of 0.7 mas/yr which is 2-8 times faster than previous VLBI kinematic estimates.