Astrometry

Comparison of multifrequency position measurements of compact extragalactic radio sources in the framework of the ICRF3
VLBI analysis of multifrequency source positions shows measurable frequency-dependent core shifts in compact extragalactic radio sources.
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Comparison of multifrequency position measurements of compact extragalactic radio sources in the framework of the ICRF3
Parsec-scale alignments of radio–optical offsets with jets in AGNs from multifrequency geodetic VLBI, Gaia EDR3, and the MOJAVE program
Alignment of multiwavelength VLBI–Gaia positions with parsec-scale jets; optical centroids are downstream and polarized, consistent with a core–jet scenario.
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Parsec-scale alignments of radio–optical offsets with jets in AGNs from multifrequency geodetic VLBI, Gaia EDR3, and the MOJAVE program
The Galactic Aberration and Its Impact on Astronomical Reference Frames
Review of Galactic aberration (~5 μas/yr) and its consequences for ICRF/Gaia frames and EOP (~1 μas/yr precession corrections).
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The Galactic Aberration and Its Impact on Astronomical Reference Frames
Revisiting astrometric parameters of quasars in Gaia-CRF2
Quality analysis of Gaia-CRF2 quasar astrometry using visibility periods and correlation coefficients; quasars with 13–16 visibility periods yield the most reliable parameters.
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Revisiting astrometric parameters of quasars in Gaia-CRF2
Systematics and accuracy of VLBI astrometry: A comparison with Gaia Data Release 2
ICRF3 vs Gaia DR2: S/X agrees at ~30 μas globally; K and X/Ka show zonal systematics, notably a >200 μas Z-glide in X/Ka.
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Systematics and accuracy of VLBI astrometry: A comparison with Gaia Data Release 2