2-6 September 2024
CJD Bonn Castell
Europe/Berlin timezone
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Contribution

CJD Bonn Castell

Source-frequency Phase-referencing Observations of AGNs with EAVN and Yebes

Speakers

  • Dr. Guang-Yao ZHAO

Primary authors

Co-authors

Content

We report results from the first successful simultaneous 22/43 GHz dual-frequency observing campaign with a joint array of the KVN, VERA, and Yebes 40m RT in 2018.

Simultaneous receiving makes it straightforward to apply frequency phase transfer (FPT) and source frequency phase referencing (SFPR) methods, which are essential for overcoming the main challenges of mm-VLBI observations and achieving astrometry.

Our analysis confirms the coherence time at 43 GHz was extended to tens of minutes after applying FPT from 22 GHz on all baselines to Yebes. These results mark the longest baseline to date (10,138 km) for the successful application of this method.

Combined with the regularized maximum likelihood (RML) imaging methods, we have achieved unprecedented angular resolutions of the observed targets.

The SFPR data also enabled us to measure the core shift of the targets and explore the magnetic field properties. Thanks to the long baseline lengths and the high-fidelity RML images, we are able to obtain core shift measurements with high precision, reaching 17$\sim$30 microarcseconds.