Effects of ICRF2 on the TRF, CRF, and EOP
The ICRF2 became official on Jan 1, 2010. It includes positions of 3414 compact radio astronomical sources observed with VLBI, a fivefold increase over the first ICRF. ICRF2 was aligned with the ICRS using 138 stable sources common to both ICRF2 and ICRF-Ext2. Maintenance of ICRF2 is to be made using 295 defining sources chosen for their historical positional stability, minimal source structure, and sky distribution. The switchover to ICRF2 has had some small effects on the terrestrial reference frame (TRF), celestial reference frame (CRF) and Earth orientation parameter (EOP) solutions from VLBI. A CRF based on ICRF2 shows a relative rotation of ~40μas with respect to ICRF, mostly about the Y-axis. Small shifts are also seen in the EOP, the largest being ~11μas in Xpole. Some small but insignificant differences are also seen in the TRF.
KeywordsICRF ICRF2 Terrestrial reference frames Celestial reference frames Earth orientation parameters
We would like to thank the International VLBI Service for Geodesy and Astrometry (IVS) and all its components, which have made the ICRF2 and this study possible. We would also like to thank the National Radio Astronomy Observatory and the VLBA for observing time and support which greatly improved the quality and the quantity of the data used in the ICRF2 and in this study. NRAO is an NSF facility operated under cooperative agreement by Associated Universities, Inc.
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