J/ApJ/454/788ivo://CDS.VizieR/J/ApJ/454/788doi:10.26093/cds/vizier.14540788CDSCote P.Welch D.L.Fischer P.Gebhardt K.2018-02-05T13:48:47Z1997-12-09T20:56:20ZCDS support team

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

cds-question@unistra.frglobular-star-clustersradial-velocityccd-photometryBV CCD frames have been used to derive surface brightness profiles for NGC 3201 which extend out to ~18'. A total of 857 radial velocities with median precision ~1km/s for 399 member giants have been used to trace the velocity dispersion profile out to 32.1' (the approximate tidal radius determined from fits of single-mass, isotropic King-Michie models to the cluster surface brightness profiles). The median difference in radial velocity for stars on either side of an imaginary axis stepped through the cluster in 1 deg increments shows a statistically significant maximum amplitude of 1.22+/-0.25km/s. We discuss several possible explanations of this result, including (1) cluster rotation, (2) preferential stripping of stars on prograde orbits near the limiting radius, (3) the projection of the cluster space velocity onto the plane of the sky, and (4) a slight drift in the velocity zero point. It is difficult to unambiguously identify the primary cause of the observed structure in the velocity field, however, and we suspect that all of the above processes may play a role. The BV surface brightness profiles and radial velocities have been modeled with both single- and multimass King-Michie models and nonparametric techniques. The corresponding density profiles and M/L profiles show good agreement over the interval 1.5<~R<~10pc, and both approaches suggest a steady rise in M/L with distance from the cluster center. Due to the low cluster luminosity we are unable to place useful constraints on the anisotropy of M/L_B~M/L_V~2.0+/-0.2 for the multimass and nonparametric models, compared to ~1.65+/-0.15 for models having equal-mass stars. Our best-fit, multimass models have mass function slopes of x~0.75+/-0.25, consistent with recent findings that the form of the mass function depends on the position relative to the potential of the Galaxy.1995ApJ...454..788Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/454/788CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/454/788https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/454/788http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/454/788https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/454/788https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/454/788http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/454/788GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/454/788/table3 (Radial velocities and photometry)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/454/788/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/454/788/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/454/788/table3?GETtext/xml+votable180.050000true153.6581667-46.26363890.0055555555555555566/38465 38467 38468https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/454/788?format=asciidefaultJ/ApJ/454/788/table3Radial velocities and photometryrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintStarStar identification numbermeta.id;meta.mainintRAJ2000Right ascension, equinox=J2000.0pos.eq.ra;meta.mainDEJ2000Declination, equinox=J2000.0pos.eq.dec;meta.mainDistDistance from cluster centerarcminpos.angDistancefloatHJDHJD of radial velocitydspect.dopplerVelocdoubleHRVHeliocentric radial velocitykm/sspect.dopplerVeloc;pos.heliocentricfloato_HRVNumber of radial velocity measurementsmeta.numberinte_HRVHRV uncertaintykm/sstat.errorfloatHRVmeanWeighted mean heliocentric radial velocitykm/sspect.dopplerVeloc;stat.meanfloate_HRVmeanHRVmean uncertaintykm/sstat.errorfloatVmagApparent V magnitudemagphot.mag;em.opt.VfloatB-VApparent B-V colormagphot.color;em.opt.B;em.opt.VfloatChi2Chi-square for radial velocitiesstat.fit.chi2floatChi2_R[]? Reduced chi-square for radial velocitiesmeta.notefloatnullableProb[0/1]? Probability of obtaining a chi-square this large purely as a consequence of measurement errorstat.probabilityfloatnullableSrcSource of photometry, 'APM' or 'CCD'meta.refcharSimbadSimbad column added by the CDSmeta.ref.urlchar