Table agn_cross_id lists sources whose positions and proper motions define the celestial reference frame of Gaia catalogue.
agn_cross_id lists the sources in Gaia (E)DR3 cross-matched to sources in a number of external AGN catalogues. The first column is the sources identifier in the external catalogue specified in the third column, the second column is the source identifier in Gaia (E)DR3.
The selection of sources and the quality of the Gaia-CRF3 are discussed in Klioner et al. (2020).
Source name in the external catalogue (see description in agn_cross_id.catalogue_name).
A unique single numerical identifier of the source obtained from gaia_source (for a detailed description see gaia_source.source_id).
A unique name for each considered external catalogue used to cross match QSOs. Only one identification is given here even if the same source occurs in more than one catalogue. Further details are given in Chapter 4 of the full documentation.