How can I cite the UCC?

If you used the UCC please reference its original article:

@ARTICLE{2023MNRAS.526.4107P,
       author = {{Perren}, Gabriel I. and {Pera}, Mar{\'\i}a S. and {Navone}, Hugo D. and {V{\'a}zquez}, Rub{\'e}n A.},
        title = "{The Unified Cluster Catalogue: towards a comprehensive and homogeneous data base of stellar clusters}",
      journal = {\mnras},
     keywords = {methods: data analysis, catalogues, open clusters and associations: general, Astrophysics - Astrophysics of Galaxies},
         year = 2023,
        month = dec,
       volume = {526},
       number = {3},
        pages = {4107-4119},
          doi = {10.1093/mnras/stad2826},
       adsurl = {https://ui.adsabs.harvard.edu/abs/2023MNRAS.526.4107P}
}

What objects are included in the UCC?

The UCC lists any object that was catalogued as an open cluster in the literature. This object might be classified differently in other articles (e.g.: moving group, association, etc.) but it will remain listed in the UCC because at least one article at some point indicated that it was an open cluster.

The UCC is regularly updated to include new research. If your article is not listed in the database, you can contact me with the details and I will add it as soon as possible.

How are member stars selected?

Membership is obtained through the fastMP method described in Section 3 of Perren et al. (2023) . The fastMP membership estimation method has been incorporated into the ASteCA package. See details here.

The search bar works in three different modes: text, equatorial coordinates, and galactic coordinates.

To use the text based search simply type in the name of the cluster and the objects with the closest matches will be listed:

Text based search

The equatorial coordinates based search can be used simply typing the (ra, dec) values:

Equatorial coordinates based search

The galactic coordinates based search is similar to the equatorial, but you need to add a g before the (lon, lat) values:

Galactic coordinates based search

What are the C1, C2, and C3 parameters?

The C1, C2, and C3 parameters are the C_phot, C_dens, and the combined class respectively, described in Sect. 4.3 of the Perren et al. (2023) article where the UCC was initially introduced.

How are probable duplicates identified?

The probable duplicates are identified using the parallax based rules described in Sect. 4.1 of Perren et al. (2023) . These are:

if parallax >= 4
    xy_r, plx_r, pm_r = 20, 0.5, 1
else 3 <= parallax < 4
    xy_r, plx_r, pm_r = 15, 0.25, 0.75
else 2 <= parallax < 3
    xy_r, plx_r, pm_r = 10, 0.2, 0.5
else 1.5 <= parallax < 2
    xy_r, plx_r, pm_r = 7.5, 0.15, 0.35
else 1 <= parallax < 1.5
    xy_r, plx_r, pm_r = 5, 0.1, 0.25
else .5 <= parallax < 1
    xy_r, plx_r, pm_r = 2.5, 0.075, 0.2
else parallax < .5
    xy_r, plx_r, pm_r = 2, 0.05, 0.15
else parallax < .25
    xy_r, plx_r, pm_r = 1.5, 0.025, 0.1
else parallax is nan
    xy_r, pm_r = 2.5, 0.2

where parallax is the associated parallax of the OC, and xy_r, plx_r, pm_r are the parallax-based thresholds for each component (in arcmin, mas, and mas/yr; respectively).

Where can I see the latest changes?

The latest changes to the UCC can be seen in the Changelog.