J/A+A/625/A50ivo://CDS.VizieR/J/A+A/625/A50doi:10.26093/cds/vizier.36250050CDSFahrion K.Georgiev I.Hilker M.Lyubenova M.van de Ven G.,Alfaro-Cuello M.Corsini E.M.Sarzi M.McDermid R.M.de Zeeuw T.2020-12-01T15:27:19Z2019-05-09T09:05:21ZCDS support team

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

cds-question@unistra.frgalaxiescatalogsradial-velocitygalaxy-classification-systemsPhotometric surveys of galaxy clusters have revealed a large number of ultra compact dwarfs (UCDs) around predominantly massive elliptical galaxies. Their origin is still debated as some UCDs are considered to be the remnant nuclei of stripped dwarf galaxies while others seem to mark the high-mass end of the star cluster population. We aim to characterize the properties of a UCD found at very close projected distance (r_wproj_=1.1kpc) from the centre of the low-mass (M~10^10^M_{sun}_) early-type galaxy FCC 47. This is a serendipitous discovery from MUSE adaptive optics science verification data. We explore the potential origin of this UCD as either a massive cluster or the remnant nucleus of a dissolved galaxy. We used archival Hubble Space Telescope data to study the photometric and structural properties of FCC 47-UCD1. In the MUSE data, the UCD is unresolved, but we used its spectrum to determine the radial velocity and metallicity. The surface brightness of FCC 47-UCD1 is best described by a single King profile with low concentration C=Rt/Rc~10 and large effective radius (r_eff_=24pc). Its integrated magnitude and blue colour (Mg=-10.55mag, (g-z)=1.46mag) combined with a metallicity of [M/H]=-1.12+/-0.10dex and an age >8Gyr obtained from the full fitting of the MUSE spectrum suggests a stellar population mass of M*=4.87x10^6^M_{sun}_. The low S/N of the MUSE spectrum prevents detailed stellar population analysis. Due to the limited spectral resolution of MUSE, we can only give an upper limit on the velocity dispersion ({sigma}<17km/s), and consequently on its dynamical mass (M_dyn_<1.3x10^7^M_{sun}_). The origin of the UCD cannot be constrained with certainty. The low metallicity, old age, and magnitude are consistent with a star cluster origin, whereas the extended size is consistent with an origin as the stripped nucleus of a dwarf galaxy with a initial stellar mass of a few 10^8^M_{sun}_.2019A&A...625A..50Fhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/625/A50CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toV/143 : Revised Bologna Catalog of M31 clusters, V.5 (Galleti+ 2012)J/A+A/416/917 : Revised Bologna Catalog of M31 globular clustersJ/MNRAS/414/3699 : Study of hot stellar systems and galaxies (Misgeld+, 2011)J/A+A/472/111 : Centaurus Compact Object Survey (Mieske+, 2007)J/ApJ/812/34 : Properties of UCD candidates in M87/M49/M60 regionsJ/AJ/142/199 : Sizes and luminosities of stellar systems (Brodie+, 2011)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/625/A50https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/625/A50http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/625/A50https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/625/A50https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/625/A50http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/625/A50GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/625/A50/tableb1 (Table of literature UCDs)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/625/A50/tableb1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/625/A50/tableb1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/625/A50/tableb1?GETtext/xml+votable180.050000true51.6371667-35.71558330.0055555555555555565/6976 6/2622-2623 2664 2704 2708 7612 24733 25083 26157 26351 27716 27719 27728 27730 27743 27764-27765 27767 27773 27912-27913 27936 27938 28045 33952 33954 34534-34535 34538 36290 38852-38853 43227 43262-43263 43626-43627https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/625/A50?format=asciiOpticaldefaultJ/A+A/625/A50/tableb1Table of literature UCDsSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameName of the UCDmeta.id;meta.ucdcharHostName of the host galaxymeta.id.parentcharRAJ2000? Right ascension (J2000)pos.eq.ra;meta.mainnullableDEJ2000? Declination (J2000)pos.eq.dec;meta.mainnullableRVRadial velocitykm/sphys.veloc;pos.heliocentricfloatVMAGAbsolute V band magnitudemagphys.magAbsfloatrprojProjected distance to hostkpcpos.distancefloatreffEffective radiuspcphys.size.radiusfloatRef[0/13]? Reference number (1)meta.id;meta.mainintnullable