J/MNRAS/438/3507ivo://CDS.VizieR/J/MNRAS/438/3507doi:10.26093/cds/vizier.74383507CDSDa Costa G.S.Held E.V.Saviane I.2024-08-08T20:12:29Z2016-08-03T08:25:24ZCDS support team

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

cds-question@unistra.frglobular-star-clustersradial-velocityline-intensitiesWe present a detailed study of the strengths of the calcium triplet absorption lines in the spectra of a large sample of red giant members of the luminous outer Galactic halo globular cluster NGC 5824. The spectra were obtained with the FORS2 and GMOS-S multi-object spectrographs at the VLT and the Gemini-S telescope, respectively. By comparing the line strengths of the NGC 5824 stars with those for red giants in clusters with well-established abundances, we conclude that there is an intrinsic abundance dispersion in NGC 5824 characterized by an inter-quartile range in [Fe/H] of 0.10dex and a total range of ~0.3dex. As for {omega} Cen and M22, the abundance distribution shows a steep rise on the metal-poor side and a shallower decline on the metal-rich side. There is also some indication that the distribution is not unimodal with perhaps three distinct abundance groupings present. NGC 5824 has a further unusual characteristic: the outer surface density profile shows no signs of a tidal cutoff. Instead, the profile has a power-law distribution with cluster stars detected to a radius exceeding 400pc. We postulate that NGC 5824 may be the remnant nuclear star cluster of a now disrupted dwarf galaxy accreted during the formation of the Galaxy's halo. We further speculate that the presence of an intrinsic [Fe/H] spread is the characteristic that distinguishes former nuclear star clusters from other globular clusters.2014MNRAS.438.3507Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/438/3507CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/438/3507https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/438/3507http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/438/3507https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/438/3507https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/438/3507http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/438/3507GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/438/3507/table1 (NGC 5824 stars observed)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/438/3507/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/438/3507/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/438/3507/table1?GETtext/xml+votable180.050000true226.1037-33.063910.0055555555555555566/44084 440863.322582951404819e-19 3.852589004194616e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/438/3507?format=asciiOpticaldefaultJ/MNRAS/438/3507/table1NGC 5824 stars observedClassClass code (1)meta.code.classcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDStar identification numbermeta.id;meta.mainintRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declinaiton (J2000)degpos.eq.dec;meta.mainVmagV magnitudemagphot.mag;em.opt.VfloatV-IV-I colour indexmagphot.color;em.opt.V;em.opt.IfloatRVRadial velocitykm/sphys.veloc;pos.heliocentricintSum(W)Ca 8542{AA} and 8862{AA} lines equivalent widths sum (W8542+W8862)0.1nmspect.line.eqWidthfloate_Sum(W)rms uncertainty on Sum(W)0.1nmstat.errorfloatW8807? Ca 8807{AA} line equivalent width0.1nmspect.line.eqWidthfloatnullablee_W8807? rms uncertainty on W88070.1nmstat.errorfloatnullableNFNumber of observations with FORS2 at the VLTmeta.numberintNGNumber of observations with GMOS-S at Gemini Southmeta.numberintSimbadSimbad column added by the CDSmeta.ref.urlchar