Effects of ICRF2 on the TRF, CRF, and EOP

Paper i proceeding, 2013

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 ICRFExt2. 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 ~40 mas with respect to ICRF, mostly about the Y-axis. Small shifts are also seen in the EOP, the largest being ~11 mas in Xpole. Some small but insignificant differences are also seen in the TRF.