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D. Mayer, J. Böhm:
"Comparing Vienna CRF solutions to Gaia-CRF2";
International Association of Geodesy Symposia, 1 (2020), 1 - 8.

We are using various models and analysis strategies, such as galactic aberration, ray-tracing etc., to create different Vienna celestial reference frame (CRF) solutions. These solutions are then compared against the Gaia reference frame (Gaia-CRF2). This is done using a degree 2 vector spherical harmonics approach. The estimated parameters are used to investigate the impact of the various analysis methods on the differences between Gaia and the Very Long Baseline Interferometry (VLBI) CRF. We find that correcting for galactic aberration reduces the difference between the Gaia-CRF2 and the VLBI CRF significantly (30 ľas in D2 and 13 ľas in D3). Furthermore, we find that using a priori ray-traced tropospheric delays in addition with low absolute constraints on tropospheric gradients reduces the ae20 parameter by 20 ľas. Using these analysis strategies we can explain almost all significant differences between the Gaia-CRF2 and the VLBI CRF. However, the vector spherical harmonic (VSH) parameter ae20 is still highly significant and can not be explained by modeling and analysis choices from the VLBI technique.

Gaia, Galactic aberration, ICRF, Reference systems

http://dx.doi.org/10.1007/1345_2020_99

https://publik.tuwien.ac.at/files/publik_290481.pdf