J/A+A/595/L2ivo://CDS.VizieR/J/A+A/595/L2doi:10.26093/cds/vizier.35959002CDSMassari D.Fiorentino G.McConnachie A.Bellini A.Tolstoy E.,Turri P.Andersen D.Bono G.Stetson P.B.Veran J.-P.2017-05-12T14:15:53Z2016-10-24T09:07:43ZCDS support team

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

cds-question@unistra.frgalaxiesglobular-star-clustersproper-motionsFor the first time the astrometric capabilities of the MCAO facility GeMS with the GSAOI camera on Gemini-South are tested to quantify the accuracy in determining stellar proper motions in the Galactic globular cluster NGC 6681. Proper motions from HST/ACS for a sample of its stars are already available, and this allows us to construct a distortion-free reference at the epoch of GeMS observations that is used to measure and correct the temporally changing distortions for each GeMS exposure. In this way, we are able to compare the corrected GeMS images with a first-epoch of HST/ACS images to recover the relative proper motion of the Sagittarius dwarf spheroidal galaxy with respect to NGC 6681. We find this to be (pm_{alpha}_cos{delta}, pm_{delta}_)=(4.09,-3.41)mas/yr, which matches previous HST/ACS measurements with a very good accuracy of 0.03mas/yr and with a comparable precision (r.m.s of 0.43mas/yr). This study successfully demonstrates that high-quality proper motions can be measured for quite large fields of view (85arcsecx85arcsec) with MCAO-assisted, ground-based cameras and provides a first, successful test of the performances of GeMS on multi-epoch data.2016A&A...595L...2Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/595/L2CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/595/L2https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/595/L2http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/595/L2https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/595/L2https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/595/L2http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/595/L2GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/595/L2/pm_tab (Stellar positions, proper motions and related errors)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/595/L2/pm_tab?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/595/L2/pm_tab?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/595/L2/pm_tab?GETtext/xml+votable180.050000true280.795445-32.30247020.005555555555555556Cone search capability for table J/A+A/595/L2/list (List of fits images)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/595/L2/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/595/L2/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/595/L2/list?GETtext/xml+votable180.050000true280.80607-32.298510.005555555555555556Associated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/A+A/595/L26/478683.2082799382822207e-19 4.2441532724171825e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/595/L2?format=asciidefaultJ/A+A/595/L2/pm_tabStellar positions, proper motions and related errorsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDStar IDmeta.id;meta.mainintXX coordinate in the Ma13 reference frame (1)pos.cartesian.x;instr.detdoubleYY coordinate in the Ma13 reference frame (1)pos.cartesian.y;instr.detdoubleF555WF555W magnitudemagphot.mag;em.opt.VfloatpmXProper motion mu(alpha)cos(delta)mas/yrpos.pm;pos.eq.rafloate_pmXrms uncertainty on pmXmas/yrstat.errorfloatpmYProper motion mu(delta)mas/yrpos.pm;pos.eq.decfloate_pmYrms uncertainty pmYmas/yrstat.errorfloatRAJ2000Right ascension (J2000) (2)degpos.eq.ra;meta.mainDEJ2000Declination (J2000) (2)degpos.eq.dec;meta.mainJ/A+A/595/L2/listList of fits imagesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension of center (J2000)degpos.eq.ra;meta.mainDEJ2000Declination of center (J2000)degpos.eq.dec;meta.mainscaleScale of the imagearcsec/pixinstr.scalefloatNxNumber of pixels along X-axismeta.numberintNyNumber of pixels along Y-axismeta.numberintsizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTextTitle of the FITS filemeta.title;meta.fitscharAssocDataAssociated Data web pagemeta.bib.pagechar