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IERS Message No. 106                                    January 22, 2007
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IERS/IVS Working Group on the Second Realization of the ICRF


The IERS Directing Board has established the Working Group on the Second
Realization of the ICRF, jointly with International VLBI Service for
Geodesy and Astrometry (IVS).

The purpose of the working group is to generate the second realization
of the ICRF from VLBI observations of extragalactic radio sources,
consistent with the current realization of the ITRF and EOP data
products. The working group will apply state-of-the-art astronomical and
geophysical models in the analysis of the entire relevant S/X
astrometric and geodetic VLBI data set. The working group will carefully
consider the selection of defining sources and the mitigation of source
position variations to improve the stability of the ICRF. The goal is to
present the second ICRF to relevant authoritative bodies, e.g. IERS and
IVS, and submit the revised ICRF to the IAU Division I working group on
the second realization of the ICRF for adoption at the 2009 IAU general
assembly.

The chair of the working group is Chopo Ma. It will meet for the first
time before the EGU General Assembly at Vienna in April 2007.

More details can be found at
http://www.iers.org/MainDisp.csl?pid=198-1100160 .

With best regards,
Chopo Ma


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