J/AJ/152/58ivo://CDS.VizieR/J/AJ/152/58doi:10.26093/cds/vizier.51520058CDSParisi M.C.Geisler D.Carraro G.Claria J.J.Villanova S.,Gramajo L.V.Sarajedini A.Grocholski A.J.2017-12-05T05:09:41Z2016-09-23T09:46:11ZCDS support team

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

cds-question@unistra.frmagellanic-cloudsstellar-associationsgiant-starsmetallicityline-intensitiesThis paper represents a major step forward in the systematic and homogeneous study of Small Magellanic Cloud (SMC) star clusters and field stars carried out by applying the calcium triplet technique. We present in this work the radial velocity and metallicity of approximately 400 red giant stars in 15 SMC fields, with typical errors of about 7km/s and 0.16dex, respectively. We added to this information our previously determined metallicity values for 29 clusters and approximately 350 field stars using the identical techniques. Using this enlarged sample, we analyze the metallicity distribution and gradient in this galaxy. We also compare the chemical properties of the clusters and of their surrounding fields. We find a number of surprising results. While the clusters, taken as a whole, show no strong evidence for a metallicity gradient (MG), the field stars exhibit a clear negative gradient in the inner region of the SMC, consistent with the recent results of Dobbie et al. For distances to the center of the galaxy less than 4{deg}, field stars show a considerably smaller metallicity dispersion than that of the clusters. However, in the external SMC regions, clusters and field stars exhibit similar metallicity dispersions. Moreover, in the inner region of the SMC, clusters appear to be concentrated in two groups: one more metal-poor and another more metal-rich than field stars. Individually considered, neither cluster group presents an MG. Most surprisingly, the MG for both stellar populations (clusters and field stars) appears to reverse sign in the outer regions of the SMC. The difference between the cluster metallicity and the mean metallicity of the surrounding field stars turns out to be a strong function of the cluster metallicity. These results could be indicating different chemical evolution histories for these two SMC stellar populations. They could also indicate variations in the chemical behavior of the SMC in its internal and external regions.2016AJ....152...58Phttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/152/58CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/149/154 : CaII spectroscopy of SMC red giants. III. (Parisi+, 2015)J/MNRAS/449/639 : VMC survey. XIV. SFR in SMC (Rubele+, 2015)J/MNRAS/442/1680 : Red giants in SMC. Abundances (Dobbie+, 2014)J/MNRAS/442/1663 : Velocities of red giants in the SMC (Dobbie+, 2014)J/AJ/139/1168 : CaII spectroscopy of SMC fields stars (Parisi+, 2010)J/AJ/138/517 : CaII spectroscopy of SMC red giants (Parisi+, 2009)J/AJ/136/1039 : CaII index of SMC red giant branch stars (Carrera+, 2008)J/MNRAS/389/678 : Extended objects in Magellanic Clouds (Bica+, 2008)J/AJ/132/1630 : CaII spectroscopy in MC clusters (Grocholski+, 2006)J/AJ/131/2514 : Radial velocities of red giants in the SMC (Harris+, 2006)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/152/58https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/152/58http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/152/58https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/152/58https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/152/58http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/152/58GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/152/58/table2 (Small Magellanic Cloud (SMC) field results)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/152/58/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/152/58/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/152/58/table2?GETtext/xml+votable180.050000true15.1271667-73.08733330.0055555555555555566/32953 32958 33287 33293 33295 33306 33313 33315 33320 33329 33330https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/152/58?format=asciidefaultJ/AJ/152/58/table2Small Magellanic Cloud (SMC) field resultsSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintPapIIINumber of stars belonging to the corresponding cluster in Paper III (Parisi et al. 2015, Cat. J/AJ/149/154)meta.numberintnullableFieldName of the selected field in SMC (G1)meta.id;meta.maincharprimaryNs[9/40] Number of stars belonging to the corresponding fieldmeta.id;obs.fieldint[Fe/H]G[-1.3/-0.7] Peak of the fitted Gaussian function ([Fe/H_G_)log(Sun)phys.luminosity.fun;stat.maxfloate_[Fe/H]G[0.03/0.08] Standard error in [Fe/H]Glog(Sun)stat.error;phys.abund.Fefloat[Fe/H]M[-1.2/-0.7] Median metallicity value ([Fe/H]_M_)log(Sun)phys.abund.Z;stat.medianfloate_[Fe/H]M[0.04/0.1] Standard error in [Fe/H]Mlog(Sun)stat.error;phys.abund.Fefloat_RAPosition from SIMBAD for the cluster surrounded by the field (right ascension part)degpos.eq.ra;meta.main_DEPosition from SIMBAD for the cluster surrounded by the field (declination part)degpos.eq.dec;meta.mainJ/AJ/152/58/table1Measured values for field starsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintFieldName of the selected field in SMC (G1)obs.fieldcharChip[MS] Chip (M=Master or S=Secondary)meta.notecharStar[1/32] Field member identification numbermeta.id;obs.fieldintV-VHB[-10.4/1.5]? Brightness difference between star and clumpmagphot.mag;arith.difffloatnullableWCaII[3.2/11.2]? Summed Ca II equivalent width ({Sigma}W); in {AA} (1)0.1nmspect.line.eqWidthfloatnullablee_WCaII[0.04/1.83]? The 1{sigma} error in WCaII ({sigma}_{Sigma}W_); in {AA}0.1nmstat.errorfloatnullable[Fe/H][-3.9/1.1]? Metallicityphys.abund.Zfloatnullablee_[Fe/H][0.07/0.68]? The error in [Fe/H]stat.error;phys.abund.Fefloatnullable