J/AJ/147/4ivo://CDS.VizieR/J/AJ/147/4doi:10.26093/cds/vizier.51470004CDSRoss T.L.Holtzman J.A.Anthony-Twarog B.J.Bond H.E.Twarog B.,Saha A.Walker A.2017-07-06T06:26:18Z2014-08-29T15:47:42ZCDS support team

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

cds-question@unistra.frglobular-star-clustersopen-star-clustershst-photometryWe quantified and calibrated the metallicity and temperature sensitivities of colors derived from nine Wide-Field Camera 3 filters on board the Hubble Space Telescope using Dartmouth isochrones and Kurucz atmosphere models. The theoretical isochrone colors were tested and calibrated against observations of five well studied galactic clusters, M92, NGC 6752, NGC 104, NGC 5927, and NGC 6791, all of which have spectroscopically determined metallicities spanning -2.30<[Fe/H]<+0.4. We found empirical corrections to the Dartmouth isochrone grid for each of the following color-magnitude diagrams (CMDs): (F555W-F814W, F814W), (F336W-F555W, F814W), (F390M-F555W, F814W), and (F390W-F555W, F814W). Using empirical corrections, we tested the accuracy and spread of the photometric metallicities assigned from CMDs and color-color diagrams (which are necessary to break the age-metallicity degeneracy). Testing three color-color diagrams [(F336W-F555W),(F390M-F555W),(F390W-F555W), versus (F555W-F814W)], we found the colors (F390M-F555W) and (F390W-F555W) to be the best suited to measure photometric metallicities. The color (F390W-F555W) requires much less integration time, but generally produces wider metallicity distributions and, at very low metallicity, the metallicity distribution function (MDF) from (F390W-F555W) is ~60% wider than that from (F390M-F555W). Using the calibrated isochrones, we recovered the overall cluster metallicity to within ~0.1dex in [Fe/H] when using CMDs (i.e., when the distance, reddening, and ages are approximately known). The measured MDF from color-color diagrams shows that this method measures metallicities of stellar clusters of unknown age and metallicity with an accuracy of ~0.2-0.5dex using F336W-F555W, ~0.15-0.25dex using F390M-F555W, and ~0.2-0.4dex with F390W-F555W, with the larger uncertainty pertaining to the lowest metallicity range.2014AJ....147....4Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/147/4CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/hst : HST Archived Exposures Catalog (STScI, 2007)VII/202 : Globular Clusters in the Milky Way (Harris, 1997)J/AJ/143/50 : White dwarfs in 47 Tuc (NGC 104) with HST (Woodley+, 2012)J/A+A/543/A106 : UBVRI photometry in NGC6791 (Brogaard+, 2012)J/A+A/492/171 : VIc light curves of NGC 6791 V20 (Grundahl+, 2008)J/AJ/130/1693 : HST-ACS observations of 5 globular clusters (Brown+, 2005)J/A+A/440/901 : Reddening and metallicity of NGC 6752 (Gratton, 2005)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/147/4https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/147/4http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/147/4https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/147/4https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/147/4http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/147/4GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/147/4/table7 (Cluster data)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/147/4/table7?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/147/4/table7?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/147/4/table7?GETtext/xml+votable180.050000true259.27937543.13283330.0055555555555555566/9666 14575 33321 41852 47125https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/147/4?format=asciiOpticaldefaultJ/AJ/147/4/table7Cluster datarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameGalactic cluster namemeta.id;meta.maincharRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.mainE(B-V)Reddeningmagphot.color.excessfloatm-MDistance modulus (m-M)_v_ (1)magphot.mag.distModfloat[Fe/H]0Lower value of spectroscopic metallicity range (from literature)log(Sun)phys.abund.Fefloat[Fe/H]1Upper value of spectroscopic metallicity range (from literature)log(Sun)phys.abund.Fefloat[Fe/H]Isochrone metallicity adoptedlog(Sun)phys.abund.Fefloat[a/Fe]l? {alpha} enhancement [{alpha}/Fe] (from literature)log(Sun)phys.abundfloatnullable[a/Fe]{alpha} enhancement [{alpha}/Fe] adoptedlog(Sun)phys.abundfloatAgeEstimated ageGyrtime.agefloatisochroneSimbad column added by the CDSmeta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlcharJ/AJ/147/4/table10Corrected isochrone sequence in color-color diagramsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[Fe/H][-2.3/0.4] Metallicity (5 values: -2.30, -1.45, -0.70, -0.40, +0.40)log(Sun)phys.abund.ZfloatV-IHST/WFC3 F555W-F814W corrected color index (1)magphot.color;em.opt.V;em.opt.Ifloatu-VHST/WFC3 F336W-F555W corrected color index (1)magphot.color;em.opt.U;em.opt.VfloatCaII-VHST/WFC3 F390M-F555W corrected color index (1)magphot.color;em.opt.B;em.opt.VfloatU-VHST/WFC3 F390W-F555W corrected color index (1)magphot.color;em.opt.U;em.opt.Vfloat