APASS DR9 Neighbourhood (gaiadr3.apassdr9_neighbourhood)

The table has 76274751 rows, 6 columns.


Table apassdr9_neighbourhood includes all good neighbours for each matched Gaia object. A good neighbour for a given Gaia source is a nearby object in the external catalogue whose position is compatible (within position errors) with the Gaia target. The cross-match algorithm is not symmetric and searches Gaia sources counterparts in APASS DR9. 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.

Reference papers:

  • 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.

More information can be found on the credit and citation instructions page.


Name Type UCD Unit Description
source_id long meta.id

Unique Gaia source identifier

clean_apassdr9_oid long meta.id.cross

External Catalogue source identifier

original_ext_source_id long meta.id.cross

Original External Catalogue source identifier

angular_distance double pos.angDistance arcsec

Angular Distance between the two sources

score double meta.code

Score of neighbours

xm_flag integer meta.code.status

Cross-match algorithm flag