J/ApJ/954/206ivo://CDS.VizieR/J/ApJ/954/206doi:10.26093/cds/vizier/ba-xt-6eCDSWang Y.Yuan H.Chen B.Chen X.Wu H.Niu Z.Huang S.Liu J.2026-07-02T12:00:32Z2025-11-27T15:53:30ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frglobular-star-clustersgalaxiestwo-color-diagramsinfrared-photometryvisible-astronomybroad-band-photometryspectroscopyWe have found 50 new globular cluster (GC) candidates around M31 with Gaia Early Data Release 3 (EDR3), with the help of Pan-STARRS1 DR1 magnitudes and Pan-Andromeda Archaeological Survey (PAndAS) images. Based on the latest Revised Bologna Catalog and simbad, we trained two random forest (RF) classifiers, the first one to distinguish extended sources from point sources and the second one to further select GCs from extended sources. From 1.85 million sources of 16^m^<g<19.5^m^ and within a large area of ~392deg2 around M31, we selected 20,658 extended sources and 1934 initial GC candidates. After visual inspection of the PAndAS images, to eliminate the contamination from noncluster sources, particularly galaxies, we finally got 50 candidates. These candidates are divided into three types (a, b, and c), according to their projected distance D to the center of M31 and their probability of being a true GC, P_GC_, which is calculated by our second RF classifier. Among these candidates, 14 are found to be associated (in projection) with the large-scale structures within the halo of M31. We also provide several simple parameter criteria for selecting extended sources effectively from Gaia EDR3, which can reach a completeness of 92.1% with a contamination fraction lower than 10%.2023ApJ...954..206Whttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/954/206CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toV/143 : Revised Bologna Catalog of M31 clusters, V.5 (Galleti+ 2012)V/156 : LAMOST DR7 catalogs (Luo+, 2019)VII/285 : Gaia DR2 quasar & galaxy classification (Bailer-Jones+, 2019)I/350 : Gaia EDR3 (Gaia Collaboration, 2020)I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)II/389 : The Pan-STARRS release 1 (PS1) Survey - DR2 (Magnier+, 2025)J/A+A/416/917 : Revised Bologna Cat. of M31 globular clusters (Galleti+, 2004)J/AJ/134/706 : New globular clusters in M 31 (Kim+, 2007)J/PASP/119/7 : HST WFPC2 star clusters in M31 (Krienke+, 2007)J/ApJS/177/174 : Star clusters in M31 (Narbutis+, 2008)J/MNRAS/402/803 : M31 globular cluster system (Peacock+, 2010)J/AJ/142/139 : A new catalog of HII regions in M31 (Azimlu+, 2011)J/ApJ/752/95 : PHAT stellar cluster survey. I. Year 1 (Johnson+, 2012)J/ApJS/199/37 : GALEX catalog of star clusters in M31 (Kang+, 2012)J/ApJ/802/127 : PHAT stellar cluster survey. II. AP catalog (Johnson+, 2015)J/ApJ/833/167 : PAndAS view of Andromeda satellites. II. (Martin+, 2016)J/ApJ/868/55 : Large-scale structure of M31. II. PAndAS (McConnachie+, 2018)J/A+A/623/A65 : Multiphot. of M31 outer halo globular clusters (Wang+, 2019)J/ApJ/899/140 : 632 Gaia Ultracompact Dwarf galaxy candidates (Voggel+, 2020)J/A+A/649/A3 : Gaia EDR3 photometric passbands (Riello+, 2021)J/A+A/658/A51 : New M31 star cluster candidates (Wang+, 2022)J/ApJ/947/34 : New velocity measurements of NGC 5128 GCs (Hughes+, 2023)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/954/206https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/954/206http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/954/206https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/954/206https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/954/206http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/954/206GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/954/206/table8 (Catalog of the 20,658 extended sources classified by Clf1 (see Section 3.2))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/954/206/table8?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/954/206/table8?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/954/206/table8?GETtext/xml+votable180.050000true16.42383529.31220.005555555555555556Cone search capability for table J/ApJ/954/206/table10 (Catalog of the visually checked globular cluster (GC) candidates)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/954/206/table10?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/954/206/table10?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/954/206/table10?GETtext/xml+votable180.050000true10.3625480640.693683060.0055555555555555562/10 4/139 142 176 178-179 184 1271 1277 5/549-551 553-555 560 562-563 574-575 710-711 728 740 744 5077-5079 5081-5083 5105 5117 6/2111 2154 2191 2195 2211 2266 2288 2290-2291 2294 2474 2834-2835 2888 2890-2891 2894 2916 2920 2964 2968 2980 2984 19967 20287 20303 20307 20323 20416-20417 20419 20428-20429 20431 20464-20465 20467 20476-20477 204791.9867573869263685e-19 3.916500758235022e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/954/206?format=asciiOpticalInfrareddefaultJ/ApJ/954/206/table8Catalog of the 20,658 extended sources classified by Clf1 (see Section 3.2)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGCcVisually checked globular cluster candidate (link to Table 10)meta.ref.urlintnullableGaiaGaia EDR3 identifiermeta.id;meta.mainRAJ2000[0/22.7] Right Ascension (J2000)degpos.eq.ra;meta.mainindexedDEJ2000[29.2/53.3] Declination (J2000)degpos.eq.dec;meta.mainindexedGmag[15.7/22.4] Gaia EDR3 G band magnitudemagphot.mag;em.optfloatgmag[15.1/19.5] Pan-STARRs g band AB magnitudemagphot.mag;em.opt.Bfloatg-r[0.001/2.2] Pan-STARRs (g-r) colormagphot.color;em.opt.B;em.opt.RfloatE(BP/RP)[0.04/2.5] Log of Gaia EDR3 bp_rp_excess parameter; Section 2.2phot.color.excess;em.opt.B;em.opt.RfloatGp-G[-4.92/0.6] Difference between predicted and observed Gaia G magnitudesmagstat.fit.residual;phot.mag;em.optfloatPext[0.5/1] Likelihood source is extended (G1)stat.likelihoodfloatPGC[0/1] Likelihood source is a globular cluster (G1)stat.likelihoodfloatPS1Display the Pan-STARRS DR2 catalog (II/389) within 3"meta.ref.urlcharJ/ApJ/954/206/table10Catalog of the visually checked globular cluster (GC) candidatesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[1/50] Identifier; same as in Figure 14meta.idintRAJ2000[0.6/22.6] Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[33.4/49.2] Declination (J2000)degpos.eq.dec;meta.mainGmag[18.3/22] Gaia EDR3 G band magnitudemagphot.mag;em.optfloatgmag[16.7/19.5] Pan-STARRs g band AB magnitudemagphot.mag;em.opt.Bfloatg-r[0.002/1.2] Pan-STARRs (g-r) colormagphot.color;em.opt.B;em.opt.RfloatE(BP/RP)[0.4/1.5] Log of Gaia EDR3 bp_rp_excess parameter; Section 2.2phot.color.excess;em.opt.B;em.opt.RfloatGp-G[-3.2/-0.7] Difference between predicted and observed Gaia G magnitudesmagstat.fit.residual;phot.mag;em.optfloatPext[0.6/1] Likelihood source is extended (G1)stat.likelihoodfloatPGC[0.27/0.97] Likelihood source is a globular cluster (G1)stat.likelihoodfloat