J/ApJS/216/19ivo://CDS.VizieR/J/ApJS/216/19doi:10.26093/cds/vizier.22160019CDSLim D.Han S.-I.Lee Y.-W.Roh D.-G.Sohn Y.-J.Chun S.-H.Lee J.-W.,Johnson C.I.2015-03-30T17:59:50Z2015-03-05T08:46:10ZCDS support team

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

cds-question@unistra.frglobular-star-clusterschemical-abundancesspectroscopyThere is increasing evidence for the presence of multiple red giant branches (RGBs) in the color-magnitude diagrams of massive globular clusters (GCs). In order to investigate the origin of this split on the RGB, we have performed new narrow-band Ca photometry and low-resolution spectroscopy for M22, NGC 1851, and NGC 288. We find significant differences (more than 4{sigma}) in calcium abundance from the spectroscopic HK' index for M22 and NGC 1851. We also find more than 8{sigma} differences in CN-band strength between the Ca-strong and Ca-weak subpopulations for these GCs. For NGC 288, however, a large difference is detected only in the CN strength. The calcium abundances of RGB stars in this GC are identical to within the errors. This is consistent with the conclusion from our new Ca photometry where the RGB splits are confirmed in M22 and NGC 1851, but not in NGC 288. We also find interesting differences in the CN-CH correlations among these GCs. While CN and CH are anti-correlated in NGC 288, they show a positive correlation in M22. NGC 1851, however, shows no difference in CH between the two groups of stars with different CN strengths. We suggest that all of these systematic differences would be best explained by how strongly Type II supernovae enrichment has contributed to the chemical evolution of these GCs.2015ApJS..216...19Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/216/19CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVII/202 : Globular Clusters in the Milky Way (Harris, 1997)J/A+A/563/A13 : Horizontal branch stars in M22 (Gratton+, 2014)J/A+A/559/A101 : NGC6656 spectroscopy of 71 blue HB stars (Salgado+, 2013)J/A+A/541/A15 : Abundances of M22 subgiants (Marino+, 2012)J/A+A/539/A19 : Horizontal branch stars in NGC 1851 (Gratton+, 2012)J/AJ/142/126 : CN & CH in SDSS Galactic globular clusters (Smolinski+, 2011)J/A+A/533/A69 : Spectroscopy of 124 RGB stars in NGC 1851 (Carretta+, 2011)J/ApJ/742/37 : Abundances of six RGB stars in M22 (Roederer+, 2011)J/A+A/524/A44 : CN and CH line strengths in 12 globulars (Pancino+, 2010)J/MNRAS/405/839 : Spectroscopic obs. of globular clusters (Sharina+, 2010)J/ApJ/705/1481 : Spectro. of stars in 6 globular clusters (Da Costa+, 2009)J/A+A/505/139 : Abundances of red giants in 17 GCs (Carretta+, 2009)J/A+A/505/117 : Abundances of red giants in 15 GCs (Carretta+, 2009)J/A+A/486/437 : CN and CH line strengths in 8 Galactic GC (Kayser+, 2008)J/ApJS/99/637 : Equivalent widths for 54 red giants (Norris+ 1995)J/PASP/107/32 : uvby-hk photometry in M22 (Anthony-Twarog+ 1995)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/216/19https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/216/19http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/216/19https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/216/19https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/216/19http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/216/19GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJS/216/19/table3 (Index measurements for the sample stars in M22 and NGC 288)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/216/19/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/216/19/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/216/19/table3?GETtext/xml+votable180.050000true279.0415-23.881450.005555555555555556Cone search capability for table J/ApJS/216/19/table4 (Index measurements for the sample stars in NGC 1851)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/216/19/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/216/19/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/216/19/table4?GETtext/xml+votable180.050000true78.43302-40.021030.0055555555555555566/16647 16658 28966 28967 28972 28973 34242 34243https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJS/216/19?format=asciiOpticaldefaultJ/ApJS/216/19/table3Index measurements for the sample stars in M22 and NGC 288hk[0.4/1.3] The hk index (1)magspect.indexfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGCGlobular cluster name (M22 or N288)meta.id.parentcharSeqStar identifier (\dicS{[LHL2015] {GC}-NNNN} in Simbad)meta.id;meta.mainintRAJ2000Right Ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainy[11.8/17.8] The Stroemgren y band magnitudemagphot.mag;em.opt.VfloatHK'[0.18/0.61] The HK' index (G1)magspect.indexfloate_HK'Error in HK'magstat.errorfloatdHK'The {delta}HK' index (deviation from fit)magstat.fit.residualfloatCN[-0.5/0.6] The CN indexmagspect.indexfloate_CNError in CNmagstat.errorfloatdCNThe {delta}CN index (deviation from fit)magstat.fit.residualfloatCH[0.8/1.4] The CH indexmagspect.indexfloate_CHError in CHmagstat.errorfloatdCHThe {delta}CH index (deviation from fit)magstat.fit.residualfloatJ/ApJS/216/19/table4Index measurements for the sample stars in NGC 1851recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGCGlobular cluster name (N1851)meta.id.parentcharSeqStar identifier (\dicS{[LHL2015] N1851-NNNN} in Simbad)meta.id;meta.mainintRAJ2000Right Ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainVmag[14.5/17.6] The V band magnitudemagphot.mag;em.opt.VfloatU-IThe (U-I) color indexmagphot.color;em.opt.U;em.opt.RfloatHK'[0.34/0.67] The HK' index (G1)magspect.indexfloate_HK'Error in HK'magstat.errorfloatdHK'The {delta}HK' index (deviation from fit)magstat.fit.residualfloatCN[-0.4/0.8] The CN indexmagspect.indexfloate_CNError in CNmagstat.errorfloatdCNThe {delta}CN index (deviation from fit)magstat.fit.residualfloatCH[0.9/1.3] The CH indexmagspect.indexfloate_CHError in CHmagstat.errorfloatdCHThe {delta}CH index (deviation from fit)magstat.fit.residualfloat