J/ApJ/929/147ivo://CDS.VizieR/J/ApJ/929/147doi:10.26093/cds/vizier.19290147CDSDumont A.Seth A.C.Strader J.Voggel K.Sand D.J.Hughes A.K.,Caldwell N.Crnojevic D.Mateo M.Bailey J.I.Forbes D.A.2025-07-18T20:13:11Z2024-04-17T09:53:17ZCDS support team

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

cds-question@unistra.frglobular-star-clustersradial-velocityvisible-astronomyspectroscopyinfrared-photometrybroad-band-photometrygalaxy-kinematicsblack-holesabsolute-magnitudeThe dense central regions of tidally disrupted galaxies can survive as ultracompact dwarfs (UCDs) that hide among the luminous globular clusters (GCs) in the halo of massive galaxies. An exciting confirmation of this model is the detection of overmassive black holes in the centers of some UCDs, which also lead to elevated dynamical mass-to-light ratios (M/Ldyn). Here we present new high-resolution spectroscopic observations of 321 luminous GC candidates in the massive galaxy NGC 5128/Centaurus A. Using these data we confirm 27 new luminous GCs, and measure velocity dispersions for 57 luminous GCs (with g-band luminosities between 2.5x10^5^ and 2.5x10^7^L_{sun}_), of which 48 are new measurements. Combining these data with size measurements from Gaia, we determine the M/L_dyn_ for all 57 luminous GCs. We see a clear bimodality in the M/L_dyn_ distribution, with a population of normal GCs with mean M/L_dyn_=1.51+/-0.31, and a second population of ~20 GCs with elevated mean M/L_dyn_=2.68+/-0.22. We show that black holes with masses ~4%-18% of the luminous GCs can explain the elevated mass-to-light ratios. Hence, it is plausible that the NGC 5128 sources with elevated M/L_dyn_ are mostly stripped galaxy nuclei that contain massive central black holes, though future high spatial resolution observations are necessary to confirm this hypothesis for individual sources. We also present a detailed discussion of an extreme outlier, VHH81-01, one of the largest and most massive GC in NGC 5128, making it an exceptionally strong candidate to be a tidally stripped nucleus.2022ApJ...929..147Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/929/147CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/371 : The Dark Energy Survey (DES): Data Release 2 (Abbott+, 2021)J/A+AS/127/409 : New nearby dwarf galaxy candidates list (Karachentseva+ 1998)J/A+AS/139/393 : Young Massive Star Clusters. II. (Larsen, 1999)J/A+A/369/812 : UVKs phot. of globular clusters in NGC 5128 (Rejkuba, 2001)J/A+A/407/1157 : UVES sky atlas (Hanuschik+, 2003)J/AJ/128/723 : Washington Photometry in NGC 5128. II (Harris+, 2004)J/ApJS/150/367 : Globular clusters in NGC 5128 (Peng+, 2004)J/AJ/130/873 : Properties of BQS objects in the SDSS DR3 area (Jester+, 2005)J/AJ/134/494 : NGC 5128 GCs UBVRICMT1 phot. & RV (Woodley+, 2007)J/MNRAS/386/1443 : 2dF study of globular clusters in NGC 5128 (Beasley+, 2008)J/MNRAS/392/879 : Globular clusters in nearby dwarf galaxies (Georgiev+, 2009)J/ApJ/722/1373 : {omega} Centauri giants abundances (Johnson+, 2010)J/ApJ/725/670 : Kinematics in the M32 nucleus (Seth, 2010)J/AJ/139/1871 : Kinematics of globulars in NGC 5128 (Woodley+, 2010)J/AJ/143/84 : New candidate globular clusters in NGC 5128 (Harris+, 2012)J/ApJ/791/107 : Parameters of NGC 5139 SGBs stars (Villanova+, 2014)J/ApJ/813/82 : z<0.06 broad-line AGN emission-line measures (Reines+, 2015)J/ApJ/805/65 : FLAMES obs. of NGC 5128's globular clusters (Taylor+, 2015)J/ApJ/850/15 : Mass-to-light ratios in early-type galaxies (Pechetti+, 2017)J/MNRAS/469/3444 : 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/858/118 : Kinematic data of 3 nearby low-mass galaxies (Nguyen+, 2018)J/ApJ/899/140 : 632 Gaia Ultracompact Dwarf galaxy candidates (Voggel+, 2020)J/ApJ/914/16 : NGC 5128 GCs from PISCes, Gaia DR2 and NSC (Hughes+, 2021)J/A+A/649/A3 : Gaia EDR3 photometric passbands (Riello+, 2021)http://datalab.noirlab.edu/nscdr2 : NOIRLab Source Catalog (NSC) homepagehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/929/147https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/929/147http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/929/147https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/929/147https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/929/147http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/929/147GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/929/147/table2 (List of all observed luminous globular clusters (GCs) candidates)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/929/147/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/929/147/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/929/147/table2?GETtext/xml+votable180.050000true200.92624389-43.565931110.0055555555555555566/43252 43254-43255 43258-43259 43261-43263 43432 43434 43604-43605https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/929/147?format=asciiOpticalInfrareddefaultJ/ApJ/929/147/table2List of all observed luminous globular clusters (GCs) candidatesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000[198.28/203.54] Right Ascension (J2000)degpos.eq.ra;meta.mainsigGCs with visually verified velocity dispersionmeta.ref.urlcharIDDiscovery identifier (G1)meta.id;meta.maincharprimaryr_IDReference for ID (1)meta.ref;pos.framecharDEJ2000[-45.22/-41.3] Declination (J2000)degpos.eq.dec;meta.mainS/N[0.78/52.5]? Signal-to-Noisestat.snrfloatnullableg0mag[14.63/23.42]? Intrinsic NOAO DR2 g band AB magnitudemagphot.mag;em.opt.BfloatnullableRVel[-147/903]? Heliocentric radial velocitykm/sspect.dopplerVeloc;pos.heliocentricfloatnullablee_RVel[2.4/158]? Uncertainty in RVelkm/sstat.error;spect.dopplerVelocfloatnullableZ[0/2]? Derived luminosity-weighted metallicityphys.abund.Zfloatnullablee_Z[0.3/0.4]? Uncertainty in Zstat.error;src.redshiftfloatnullablesetupInstrument and setup used (G2)instr.setupcharMmCandidate has RVel expected for Cen A GC? (2)meta.code.membercharRefLiterature source of candidate (G3)meta.bibcharrCatDisplay data from Voggel+ 2020, J/ApJ/899/140 ; Hughes+ 2021, J/ApJ/914/16 and Harris+ 2012, J/AJ/143/84 and Woodley+ 2010, J/AJ/139/1871 within 3"meta.ref.urlintnullableSimbadNameSimbad column added by the CDSmeta.idcharnullableJ/ApJ/929/147/table3List of 57 luminous GCs with visually verified velocity dispersionr_rhmReference for rhm (2)meta.ref;pos.framecharIDDiscovery identifier (G1)meta.id;meta.maincharE_BHMass[90000/1030000]? Upper uncertainty in BHMasssolMassstat.error;stat.maxdoublenullablee_BHMass[12000/174000]? Lower uncertainty in BHMasssolMassstat.errordoublenullableRefLiterature source of candidate (G3)meta.bibcharf_ID[*] Flag on ID (1)meta.codecharsetupInstrument and setup used (G2)instr.setupcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRVel[280/903] Heliocentric radial velocitykm/sspect.dopplerVeloc;pos.heliocentricfloate_RVel[2.4/6.1] Uncertainty in RVelkm/sstat.error;spect.dopplerVelocfloatsigma[6.5/22] Derived velocity dispersionkm/sphys.veloc.dispersionfloate_sigma[0.8/5] Uncertainty in sigmakm/sstat.errorfloatsigmaGl[5.8/21.5] Global velocity dispersion; See Section 5km/sphys.veloc.dispersionfloatrhm[0.13/1.8] Calculated half-mass radiusarcsecphys.angSize;srcfloatVMag[-11.1/-8.6] Absolute V band Vega magnitude (3)magphys.magAbs;em.opt.VfloatE(B-V)[0.08/0.2] Color excess in (B-V) used for Vmagmagphot.color.excessfloatM/LV[0.8/7.2] V band mass-to-light ratioSunphys.composition.massLightRatiofloatE_M/LV[0.2/1.2] Upper uncertainty in M/LVSunstat.error;stat.maxfloate_M/LV[0.18/1.1] Lower uncertainty in M/LVSunstat.errorfloatBHMass[76000/861000]? Predicted Black Hole mass (4)solMassphys.massdoublenullable