The ICRF-Ext.2

This maintenance/extension catalog ICRF-Ext2 (Fey et al., 2004) contains all the observed extragalactic sources in the VLBI astrometric/geodetic data set. VLBI data obtained between 1999 May and the end of 2002 May together with older data have been used for this second extension and revision of the ICRF. Around 1.2 million new observations from approximately 400 sessions were added since ICRF-Ext1.

Based on inclusion of the additional data, ICRF candidate and "other" sources positions have been revised. Positions in the frame of ICRF, for additional 109 new sources (with respect to the 608 ICRF sources) are also given. All but four of the new sources are located north of declination -30°. Like for the ICRF-Ext1, positions of the ICRF defining sources remain unchanged. As in the original ICRF, the formal errors were inflated applying an additive variance and a scaling factor to provide more realistic errors.

 

All	List		717 objects.
Defining	List		212 objects.
Candidate	List		294 objects.
Other	List		102 objects.
New	List		109 objects.

ICRF-Ext.2 catalog, from CDS, in VO (Virtual Observatory) format