J/ApJ/899/140ivo://CDS.VizieR/J/ApJ/899/140doi:10.26093/cds/vizier.18990140CDSVoggel K.T.Seth A.C.Sand D.J.Hughes A.Strader J.Crnojevic D.,Caldwell N.2023-06-14T12:45:19Z2021-11-05T06:29:54ZCDS support team

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

cds-question@unistra.frglobular-star-clustersgalaxiesvisible-astronomyphotometrytwo-color-diagramsTidally stripped galaxy nuclei and luminous globular clusters (GCs) are important tracers of the halos and assembly histories of nearby galaxies, but are difficult to reliably identify with typical ground-based imaging data. In this paper we present a new method to find these massive star clusters using Gaia DR2, focusing on the massive elliptical galaxy Centaurus A (Cen A). We show that stripped nuclei and GCs are partially resolved by Gaia at the distance of Cen A, showing characteristic astrometric and photometric signatures. We use this selection method to produce a list of 632 new candidate luminous clusters in the halo of Cen A out to a projected radius of 150kpc. Adding in broadband photometry and visual examination improves the accuracy of our classification. In a spectroscopic pilot program we have confirmed five new luminous clusters, which includes the 7th and 10th most luminous GC in Cen A. Three of the newly discovered GCs are further away from Cen A than all previously known GCs. Several of these are compelling candidates for stripped nuclei. We show that our novel Gaia selection method retains at least partial utility out to distances of ~25Mpc and hence is a powerful tool for finding and studying star clusters in the sparse outskirts of galaxies in the local universe.2020ApJ...899..140Vhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/899/140CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/345 : Gaia DR2 (Gaia Collaboration, 2018)J/ApJS/150/367 : Globular clusters in NGC 5128 (Peng+, 2004)J/AJ/132/2187 : MCT1 photometry of NGC 5128 globular clusters (Harris+, 2006)J/AJ/134/494 : NGC5128 globular clusters UBVRICMT1 phot. & RV (Woodley+,2007)J/MNRAS/386/1443 : 2dF study of globular clusters in NGC 5128 (Beasley+, 2008)J/A+A/523/A48 : Gaia photometry (Jordi+, 2010)J/AJ/139/1871 : Kinematics of globulars in NGC 5128 (Woodley+, 2010)J/ApJ/708/1335 : Spectroscopy of globulars in NGC 5128 (Woodley+, 2010)J/AJ/142/199 : Sizes and luminosities of stellar systems (Brodie+, 2011)J/AJ/143/84 : New candidate globular clusters in NGC 5128 (Harris+, 2012)J/ApJ/760/87 : Globular clusters of M60 with HST (Strader+, 2012)J/AJ/145/101 : Updated nearby galaxy catalog (Karachentsev+, 2013)J/MNRAS/445/2385 : HST/ACS Coma Cluster Survey. X. (den Brok+, 2014)J/MNRAS/441/3570 : Nuclear star clusters 228 spiral galaxies (Georgiev+, 2014)J/MNRAS/443/1151 : AIMSS Project. I. Compact Stellar Systems (Norris+, 2014)J/ApJ/812/34 : Properties UCD candidates in M87/M49/M60 regions (Liu+, 2015)J/MNRAS/457/2122 : Nuclear star clusters photometric masses (Georgiev+, 2016)J/A+A/586/A102 : UCDs in the halo of NGC1399 (Voggel+, 2016)J/MNRAS/469/3444 : Survey Centaurus A's Baryonic Structures II. (Taylor+, 2017)J/ApJ/858/102 : Gemini/NIFS and HST obs. of the galaxy M59-UCD3 (Ahn+, 2018)J/ApJ/878/18 : NGVS. XXIII. Nuclear star clusters (Sanchez-Janssen+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/899/140https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/899/140http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/899/140https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/899/140https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/899/140http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/899/140GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/899/140/table2 (List of Gaia ultra compact dwarf (UCD) candidates)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/899/140/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/899/140/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/899/140/table2?GETtext/xml+votable180.050000true198.276663062-42.99380527930.005555555555555556Cone search capability for table J/ApJ/899/140/table3 (List of MIKE spectroscopic targets of Gaia-based UCD candidates)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/899/140/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/899/140/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/899/140/table3?GETtext/xml+votable180.050000true202.432394-42.3914040.005555555555555556Cone search capability for table J/ApJ/899/140/table4 (List of the 57 previously confirmed UCDs that were used to assess completeness in Figure 1)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/899/140/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/899/140/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/899/140/table4?GETtext/xml+votable180.050000true200.90965389-42.773053060.0055555555555555565/10813 10815 10858 10900-10901 6/43251 43257-43259 43424 43426-43427 43608-43609 43612-43613 43776 437781.9867573869263685e-19 3.916500758235022e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/899/140?format=asciiOpticaldefaultJ/ApJ/899/140/table2List of Gaia ultra compact dwarf (UCD) candidatesRankRankmeta.codecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintKV19KV19 sequential identifiermeta.id;meta.maincharprimaryRAJ2000[198/205] Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[-46/-40] Declination (J2000)degpos.eq.dec;meta.mainGaiaDisplay data from Gaia DR2 (II/345) within 0.5"meta.ref.urlintnullableAEN[0.26/15.42] Gaia DR2 Astrometric Excess Noiseinstr.det.noisefloatGmag[11.23/19.0] Gaia DR2 Gmagmagphot.mag;em.opt.VfloatBP-RP[1.4/4.97] Gaia DR2 BP/RP Excess Factorphot.color.excessfloatu-r[0.41/3.41]? u-r color (1)magphot.color;em.opt.U;em.opt.Rfloatnullabler-z[-0.55/0.91]? r-z color (1)magphot.color;em.IR;em.IRfloatnullablermag[14.23/18.21]? r band magnitude (1)magphot.mag;em.opt.RfloatnullableVotes[1/5]? final visual assessment scoremeta.codefloatnullableCL[0/5.08]? Cluster Likelihoodstat.likelihoodfloatnullableMIKEIndicates that this source is available in MIKE spectroscopic targets (table3)meta.ref.urlcharJ/ApJ/899/140/table3List of MIKE spectroscopic targets of Gaia-based UCD candidatesSimbadNameSimbad column added by the CDSmeta.idcharnullableKV19KV19 sequential identifiermeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintLabelNew confirmed UCD labelsmeta.codecharRAJ2000[199/204] Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[-46/-41] Declination (J2000)degpos.eq.dec;meta.maingmag[15.18/18.3] apparent g band magnitudemagphot.mag;em.optfloatgMAG[-10.32/-9.61]? absolute g band magnitudemagphys.magAbsfloatnullableRVel[-95.2/719.2] Radial Velocitykm/sphys.veloc;pos.heliocentricfloate_RVel[1.2/32.7] Uncertainty in RVelkm/sstat.error;spect.dopplerVelocfloatS/N[5.2/23] Signal to noisestat.snrfloatCL[0.0001/5.08]? Cluster Likelihoodstat.likelihoodfloatnullableVotes[1/3.75]? final visual assessment scoremeta.codefloatnullableGaiaDisplay data from Gaia DR2 (II/345) within 0.5"meta.ref.urlintnullableJ/ApJ/899/140/table4List of the 57 previously confirmed UCDs that were used to assess completeness in Figure 1SimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameTaylor+, 2017, J/MNRAS/469/3444 designationmeta.id;meta.maincharRAJ2000[200/202] Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[-44/-42] Declination (J2000)degpos.eq.dec;meta.mainGmag[17.39/19.54] Gaia DR2 G band magnitudemagphot.mag;em.opt.VfloatAEN[1.76/15.29] Gaia DR2 Astrometric Excess Noiseinstr.det.noisefloatBP-RP[1.78/3.1] Gaia DR2 BP/RP Excess Factorphot.color.excessfloatgmag[17.02/18.77] g' band mag from Taylor+magphot.mag;em.optfloat