J/ApJ/873/65ivo://CDS.VizieR/J/ApJ/873/65doi:10.26093/cds/vizier.18730065CDSSakai S.Lu J.R.Ghez A.Jia S.Do T.Witzel G.Gautam A.K.Hees A.,Becklin E.Matthews K.Hosek M.W.2020-11-29T06:56:49Z2020-09-02T12:34:45ZCDS support team

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

cds-question@unistra.frastrometryinfrared-photometrygalactic-centerPrecision measurements of the stars in short-period orbits around the supermassive black hole at the Galactic Center are now being used to constrain general relativistic effects, such as the gravitational redshift and periapse precession. One of the largest systematic uncertainties in the measured orbits has been errors in the astrometric reference frame, which is derived from seven infrared-bright stars associated with SiO masers that have extremely accurate radio positions, measured in the Sgr A*-rest frame. We have improved the astrometric reference frame within 14" of the Galactic Center by a factor of 2.5 in position and a factor of 5 in proper motion. In the new reference frame, Sgr A* is localized to within a position of 0.645mas and proper motion of 0.03mas/yr. We have removed a substantial rotation (2.25{deg} per decade), that was present in the previous less-accurate reference frame used to measure stellar orbits in the field. With our improved methods and continued monitoring of the masers, we predict that orbital precession predicted by general relativity will become detectable in the next ~5yr.2019ApJ...873...65Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/873/65CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/470/191 : Mid-IR and radio interferometry of S Ori (Wittkowski+, 2007)J/A+A/511/A18 : NIR observations of stars near SgrA* (Schoedel+, 2010)J/ApJ/725/331 : Astrometry in the Galactic Center (Yelda+, 2010)J/A+A/557/A82 : NIR polarimetry of Galactic center sources (Buchholz+, 2013)J/ApJ/783/131 : Kinematic of stars in Galactic center (Yelda+, 2014)J/ApJ/830/17 : GC secondary IR astrometric standards (Boehle+, 2016)J/ApJ/863/15 : Spitzer, VLT and Keck NIR light curves of SgrA* (Witzel+, 2018)J/A+A/618/L10 : SgrA* orbital motions with GRAVITY (GRAVITY Col., 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/873/65https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/873/65http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/873/65https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/873/65https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/873/65http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/873/65GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/873/65/table2 (Galactic Center secondary IR astrometric standard and point-spread function (PSF) stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/873/65/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/873/65/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/873/65/table2?GETtext/xml+votable180.050000true266.4168211-29.00792360.0055555555555555566/28830https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/873/65?format=asciiInfrareddefaultJ/ApJ/873/65/table2Galactic Center secondary IR astrometric standard and point-spread function (PSF) starsSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameName of the standardmeta.id;meta.maincharK'mag[7.4/15.7] K' magnitudemagphot.mag;em.IR.KfloatT0[2009.4/2013.8] Average time of the IR positional measurementyrtime.epoch;stat.meanfloatRad[0.36/17.6] Radiusarcsecphys.angSize;srcfloatdRA[-6.4/15.5] Positional offset in RA (1)arcsecpos.eq.ra;arith.difffloate_dRA[0.05/1.1] Uncertainty in dRA, milli-arcsec (2)masstat.errorfloatdDE[-9.52/12.31] Positional offset in DE (1)arcsecpos.eq.dec;arith.difffloate_dDE[0.06/3.5] Uncertainty in dDE, milli-arcsec (2)masstat.errorfloatvRA[-9.01/13.4] Velocity fit in RAmas/yrphys.veloc;pos.eq.rafloate_vRA[0.009/0.4] Uncertainty in vRA (3)mas/yrstat.errorfloatvDE[-9.3/11.2] Velocity fit in DEmas/yrphys.veloc;pos.eq.decfloate_vDE[0.016/0.9] Uncertainty in vDE (3)mas/yrstat.errorfloatStd[Y/N] Astrometric Standard (4)meta.codecharPSFPSF Star (5)obs.fieldchar_RAPosition, computed from SIMBAD Sgr A* position (17:45:40.0359-29:00:28.169) with dRA and dDE offsets (right ascension part)degpos.eq.ra;meta.main_DEPosition, computed from SIMBAD Sgr A* position (17:45:40.0359-29:00:28.169) with dRA and dDE offsets (declination part)degpos.eq.dec;meta.main