• Received : 2015.09.02
  • Accepted : 2015.10.15
  • Published : 2015.10.31


We present our efforts for extending the simultaneous multi-frequency receiver system of the Korean Very Long Baseline Interferometry (VLBI) Network (KVN) to global baselines in order to measure the frequency-dependent position shifts in Active Galactic Nuclei (AGN) jets, the so called core shift effect, with an unprecedented accuracy (a few micro-arcseconds). Millimeter VLBI observations with simultaneous multi-frequency receiver systems, like those of the KVN, enable us to explore the innermost regions of AGN and high precision astrometry. Such a system is capable of locating the frequency dependent opacity changes accurately. We have conducted the feasibility test-observations with the interested partners by implementing the KVN-compatible systems. Here we describe the science case for measuring the core shift effect in the AGN jet and report progress and future plans on extending the simultaneous multi-frequency system to global baselines.


techniques: interferometeric;astrometry;high angular resolution;radio continuum: active galactic nuclei


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Grant : 활동성은하핵 코어이동 현상연구