J/MNRAS/454/2621ivo://CDS.VizieR/J/MNRAS/454/2621doi:10.26093/cds/vizier.74542621CDSMalavolta L.Piotto G.Bedin L.R.Sneden C.Nascimbeni V.Sommariva V.2024-08-15T20:16:00Z2016-09-23T14:23:46ZCDS support team

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

cds-question@unistra.frglobular-star-clustersradial-velocityWe present a detailed study of the internal kinematics of the Galactic globular cluster M 4 (NGC 6121), by deriving the radial velocities from 7250 spectra for 2771 stars distributed from the upper part of the red giant branch down to the main sequence. We describe new approaches to determine the wavelength solution from day-time calibrations and to determine the radial velocity drifts that can occur between calibration and science observations when observing with the GIRAFFE spectrograph at Very Large Telescope. Two techniques to determine the radial velocity are compared, after a qualitative description of their advantages with respect to other commonly used algorithm, and a new approach to remove the sky contribution from the spectra obtained with fibre-fed spectrograph and further improve the radial velocity precision is presented. The average radial velocity of the cluster is <v>=71.08+/-0.08km/s with an average dispersion of {mu}_vc_=3.97km/s. Using the same data set and the same statistical approach of previous analyses, 20 additional binary candidates are found, for a total of 87 candidates. A new determination of the internal radial velocity dispersion as a function of cluster distance is presented, resulting in a dispersion of 4.5km/s within 2-arcmin from the centre of cluster and steadily decreasing outward. We statistically confirm the small amplitude of the cluster rotation, as suggested in the past by several authors. This new analysis represents a significant improvement with respect to previous results in literature and provides a fundamental observational input for the modelling of the cluster dynamics.2015MNRAS.454.2621Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/454/2621CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJS/120/265 : HST photometry of M4 (Ibata+, 1999)J/MNRAS/442/2381 : Variable stars in M4 primary field (Nascimbeni+, 2014)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/454/2621https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/454/2621http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/454/2621https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/454/2621https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/454/2621http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/454/2621GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/454/2621/table3 (Average RVs of 2719 stars of the sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/454/2621/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/454/2621/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/454/2621/table3?GETtext/xml+votable180.050000true245.86279194-26.387166940.0055555555555555566/42955https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/454/2621?format=asciidefaultJ/MNRAS/454/2621/table3Average RVs of 2719 stars of the samplerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Rigth ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainIDIdentification numbermeta.id;meta.mainintVmagV magnitudemagphot.mag;em.opt.VfloatB-VB-V colour indexmagphot.color;em.opt.B;em.opt.VfloatV0magDereddened V magnitudemagphot.mag.reddFree;em.opt.Vfloat(B-V)0Dereddened B-V colour indexmagphot.color;em.opt.B;em.opt.Vfloato_VmagNumber of observationsmeta.numberintRVMean radial velocitykm/sphys.veloc;pos.heliocentricdoublesigma? Radial velocity dispersionkm/sspect.dopplerVelocfloatnullable<sigma>Average radial velocity dispersionkm/sphys.veloc.dispersionfloatstdratiosigma/<sigma> ratiostat.errordoubleSimbadSimbad column added by the CDSmeta.ref.urlcharJ/MNRAS/454/2621/table4Individual RVs of 2730 stars of the sampleFibFiber numbermeta.idintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDIdentification numbermeta.id;meta.mainintMJDModified Julian datedtime.epochdoublejj index referring to individual exposuremeta.idintGIRFileGIRAFFE file namemeta.id;meta.filecharBERVBarycentric earth radial velocitykm/sspect.dopplerVeloc;pos.earth;pos.eopfloatvobsrjObserved velocity, vobs_r,j_ (1)km/sphys.velocdoublevrjVelocity, v_r,j_(1)km/sphys.velocdoubleFWHMFull width at half maximumkm/sspect.line.widthfloatSNRSignql-to-noise ratiostat.snr;arith.ratiofloat1/chi2Inverse of {chi}2meta.notedouble