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arXiv · 2205.00092

Inverse Multview I: Multi-Calibrator inverse phase referencing for Microarcsecond VLBI Astrometry

Lucas J. Hyland·Mark J. Reid·Simon P. Ellingsen·Maria J. Rioja·Richard Dodson·Gabor Orosz·Colin R. Masson·Jamie M. McCallum
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Abstract

Very Long Baseline Interferometry (VLBI) astrometry is a well established technique for achieving $\pm10~μ$as parallax accuracies at frequencies well above 10~GHz. At lower frequencies, uncompensated interferometer delays associated with the ionosphere play the dominant role in limiting the astrometric accuracy. Multiview is a novel VLBI calibration method, which uses observations of multiple quasars to accurately model and remove time-variable, directional-dependent changes to the interferometer delay. Here we extend the Multiview technique by phase referencing data to the target source ("inverse Multiview") and test its performance. Multiple observations with a four-antenna VLBI array operating at 8.3~GHz show single-epoch astrometric accuracies near $20~μ$as for target-reference quasar separations up to about 7 degrees. This represents an improvement in astrometric accuracy by up to an order of magnitude compared to standard phase referencing.

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Lucas J. Hyland, Mark J. Reid, Simon P. Ellingsen, Maria J. Rioja, Richard Dodson, Gabor Orosz, Colin R. Masson, Jamie M. McCallum. 2023-02-14. Inverse Multview I: Multi-Calibrator inverse phase referencing for Microarcsecond VLBI Astrometry. https://doi.org/10.3847/1538-4357%2Fac6d5b

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