Comparison of Gaia DR2 Parallaxes of Stars with VLBI Astrometry.

We compare the parallaxes of stars from VLBI astrometry in the literature to those in the Gaia DR2 catalog. Our full sample contains young stellar objects, evolved AGB stars, pulsars, and other radio stars. Excluding AGB stars, which show significant discrepancies between Gaia and VLBI parallaxes, and stars in binary systems, we obtain an average, systematic, parallax offset of −75 ± 29 μas for Gaia DR2, consistent with their estimate of a parallax zero-point between −100 and 0 μas. [ABSTRACT FROM AUTHOR]