URAT-1 Best Neighbour (gaiadr3.urat1_best_neighbour)
The table has 227682883 rows, 7 columns.
urat1_best_neighbour lists each matched Gaia object with its best neighbour in the external catalogue. The cross-match algorithm is not symmetric and searches Gaia sources counterparts in URAT-1. The best neighbour is chosen among good neighbours as the one with the highest value of the figure of merit, which evaluates the ratio between two opposite models/hypotheses: the counterpart candidate is a match or it is found by chance. Good neighbours are nearby objects in the external catalogue whose position is compatible within position errors with the Gaia target. The cross-match algorithm is positional and exploits the full 5 parameter covariance matrix of the Gaia astrometric solution when available and the external catalogue positions and position errors. In addition it takes into account the external catalogue environment using the local density.
Please note that the cross-match algorithm is a trade-off between multiple requirements, in particular between completeness and correctness. It is thus not limited to a simple cone search.
- Marrese et al. (2017)
- Marrese et al. (2019)
If you have used Gaia data in your research, please use the following acknowledgement:
This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement.
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Unique Gaia source identifier
Original External Catalogue source identifier
Angular Distance between the two sources
Cross-match algorithm flag
External Catalogue source identifier
Number of neighbours in External Catalogue
Number of mates in Gaia Catalogue