Significant core shift variability in parsec-scale jets of active galactic nuclei

Understand

The apparent position of jet base (core) in radio-loud active galactic nuclei changes with frequency because of synchrotron self-absorption.

• Studying this `core shift` effect enables us to reconstruct properties of the jet regions close to the central engine.
• We report here results from core shift measurements in AGNs observed with global VLBI at 2 and 8 GHz at epochs from 1994 to 2016.
• Our sample contains 40 objects observed at least 10 times during that period.