J/AJ/149/153 Abundances of red giants in 10 globular clusters (Meszaros+, 2015) ================================================================================ Exploring anticorrelations and light element variations in northern globular clusters observed by the APOGEE survey. Meszaros S., Martell S.L., Shetrone M., Lucatello S., Troup N.W., Bovy J., Cunha K., Garcia-Hernandez D.A., Overbeek J.C., Allende Prieto C., Beers T.C., Frinchaboy P.M., Garcia Perez A.E., Hearty F.R., Holtzman J., Majewski S.R., Nidever D.L., Schiavon R.P., Schneider D.P., Sobeck J.S., Smith V.V., Zamora O., Zasowski G. =2015AJ....149..153M ================================================================================ ADC_Keywords: Clusters, globular ; Stars, giant ; Abundances Keywords: stars: abundances - stars: AGB and post-AGB - stars: chemically peculiar - stars: evolution Abstract: We investigate the light-element behavior of red giant stars in northern globular clusters (GCs) observed by the SDSS-III Apache Point Observatory Galactic Evolution Experiment. We derive abundances of 9 elements (Fe, C, N, O, Mg, Al, Si, Ca, and Ti) for 428 red giant stars in 10 GCs. The intrinsic abundance range relative to measurement errors is examined, and the well-known C-N and Mg-Al anticorrelations are explored using an extreme-deconvolution code for the first time in a consistent way. We find that Mg and Al drive the population membership in most clusters, except in M107 and M71, the two most metal-rich clusters in our study, where the grouping is most sensitive to N. We also find a diversity in the abundance distributions, with some clusters exhibiting clear abundance bimodalities (for example M3 and M53) while others show extended distributions. The spread of Al abundances increases significantly as cluster average metallicity decreases as previously found by other works, which we take as evidence that low metallicity, intermediate mass AGB polluters were more common in the more metal-poor clusters. The statistically significant correlation of [Al/Fe] with [Si/Fe] in M15 suggests that ^28^Si leakage has occurred in this cluster. We also present C, N, and O abundances for stars cooler than 4500K and examine the behavior of A(C+N+O) in each cluster as a function of temperature and [Al/Fe]. The scatter of A(C+N+O) is close to its estimated uncertainty in all clusters and independent of stellar temperature. A(C+N+O) exhibits small correlations and anticorrelations with [Al/Fe] in M3 and M13, but we cannot be certain about these relations given the size of our abundance uncertainties. Star-to-star variations of {alpha}-element (Si, Ca, Ti) abundances are comparable to our estimated errors in all clusters. Description: We investigated the abundances of nine elements (Fe, C, N, O, Mg, Al, Si, Ca, Ti) for 428 stars in 10 globular clusters (NGC 7078, NGC 6341, NGC 5024, NGC 5466, NGC 6205, NGC 7089, NGC 5272, NGC 5904, NGC 6171, and NGC 6838) using Apache Point Observatory Galactic Evolution Experiment (APOGEE; Majewski et al. 2015, cat. J/AJ/149/7) DR10 spectra. The APOGEE is a three-year, near-infrared (15090-16990{AA}), high-resolution spectroscopic survey of about 100000 red giant stars included as part of the third Sloan Digital Sky Survey (SDSS-III; Eisenstein et al., 2011AJ....142...72E). With a nominal resolving power of 22500, APOGEE is deriving abundances of up to 15 elements for nearly 100000 stars. APOGEE is in a unique position among the various Galactic spectroscopic surveys, as it uses the Sloan 2.5m telescope at Apache Point Observatory, and thereby has access to the northern hemisphere. APOGEE observes a large sample of northern globular clusters. The spectra used in this paper are publicly available as part of the 10th data release (DR10; Ahn et al., 2014ApJS..211...17A) of SDSS-III. The initial set of stars selected were the same used by Meszaros et al. 2013 (cat. J/AJ/146/133) to check the accuracy and precision of APOGEE parameters published in DR10. However, instead of using the automatic APOGEE Stellar Parameters and Chemical Abundances Pipeline (ASPCAP), we will make use of photometry and theoretical isochrones to constrain the effective temperature (T_eff_) and surface gravity log(g) and use an independent semi-automated method for elemental abundance determination for 10 northern globular clusters. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table1.dat 33 10 Properties of clusters from the literature table2.dat 95 428 Properties of stars analyzed table5.dat 114 289 Identifiers, stellar parameters, and elemental abundances from the literature for stars in our sample refs.dat 64 31 References -------------------------------------------------------------------------------- See also: II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003) VII/202 : Globular Clusters in the Milky Way (Harris, 1997) J/AJ/149/7 : SDSS-III/APOGEE. I. Be stars (Chojnowski+, 2015) J/AJ/148/24 : Extinction maps in the bulge from APOGEE (Schultheis+, 2014) J/AJ/146/156 : APOGEE M-dwarf survey. I. (Deshpande+, 2013) J/AJ/146/133 : Stellar parameters from SDSS-III APOGEE DR10 (Meszaros+, 2013) J/ApJ/754/L38 : Abundances & radial velocities of M13 giants (Johnson+, 2012) J/AJ/141/175 : Abundances in M15 RGB/RHB stars (Sobeck+, 2011) J/AJ/141/62 : M5 chemical abundances for evolved stars (Lai+, 2011) J/AJ/140/1119 : Radial velocities of NGC 5466 members (Shetrone+, 2010) J/AJ/139/2289 : Abundances of five red giants in M5 (Koch+, 2010) 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/ApJ/689/1031 : Heavy element abundances in giant stars (Yong+, 2008) J/A+A/464/967 : Abundances of red giants in NGC 6388 (Carretta+, 2007) J/ApJ/638/1018 : Equivalent widths for giant stars in M13 and M71 (Yong+, 2006) J/AJ/129/303 : Abundances of stars in M3 and M13 (Cohen+, 2005) J/AJ/120/1364 : Abundances in M3 and M13 (Cavallo+, 2000) http://sdss3.org/ : SDSS-III website Byte-by-byte Description of file: table1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 3 A3 --- --- [NGC] 5- 8 I4 --- NGC NGC number of the cluster 10- 14 A5 --- Cluster Cluster name 15- 17 I3 --- Nst [8/122] Number of stars observed in cluster 19- 23 F5.2 [Sun] [Fe/H] Log Fe/H number abundance (1) 25- 28 F4.2 [Sun] e_[Fe/H] Uncertainty in [Fe/H] 30- 33 F4.2 mag E(B-V) The (B-V) color excess (2) -------------------------------------------------------------------------------- Note (1): From Harris 1996 (cat. VII/195, cat. VII/202) 2010 edition. Clusters are listed in order of the average cluster metallicity determined in this paper. Note (2): From Harris 1996 (cat. VII/195, cat. VII/202) 2010 edition. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table2.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 2 A2 --- --- [2M] 3- 18 A16 --- 2MASS Star 2MASS identifier (HHMMSSss+DDMMSSs, J2000) 20- 24 A5 --- Cluster Cluster name 26- 31 F6.1 km/s HV Heliocentric velocity 33- 36 I4 K Teff Photometric effective temperature 38- 41 F4.2 [cm/s2] logg [0.3/4] Log surface gravity; from isochrones 43- 47 F5.2 [Sun] [Fe/H] [-2.6/-0.6] Log Fe/H abundance 49- 53 F5.2 [Sun] [C/Fe] ? Log C/Fe abundance 55- 59 F5.2 [Sun] [N/Fe] ? Log N/Fe abundance 61- 65 F5.2 [Sun] [O/Fe] ? Log O/Fe abundance 67- 71 F5.2 [Sun] [Mg/Fe] ? Log Mg/Fe abundance 73- 77 F5.2 [Sun] [Al/Fe] ? Log Al/Fe abundance 79- 83 F5.2 [Sun] [Si/Fe] ? Log Si/Fe abundance 85- 89 F5.2 [Sun] [Ca/Fe] ? Log Ca/Fe abundance 91- 95 F5.2 [Sun] [Ti/Fe] ? Log Ti/Fe abundance -------------------------------------------------------------------------------- Byte-by-byte Description of file: table5.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 2 A2 --- --- [2M] 3- 18 A16 --- 2MASS Star 2MASS identifier (HHMMSSss+DDMMSSs, J2000) 20- 23 A4 --- Cluster Cluster name 25- 28 I4 K Teff ? Effective temperature 30- 33 F4.2 [cm/s2] logg ? Log surface gravity 35- 40 F6.3 [Sun] [Fe/H] ? Log Fe/H abundance 42- 46 F5.2 [Sun] [C/Fe] ? Log C/Fe abundance 48- 52 F5.2 [Sun] [N/Fe] ? Log N/Fe abundance 54- 59 F6.3 [Sun] [O/Fe] ? Log O/Fe abundance 61- 66 F6.3 [Sun] [Mg/Fe] ? Log Mg/Fe abundance 68 A1 --- l_[Al/Fe] [<] Upper limit flag on [Al/Fe] 69- 74 F6.3 [Sun] [Al/Fe] ? Log Al/Fe abundance 76- 80 F5.3 [Sun] [Si/Fe] ? Log Si/Fe abundance 82- 86 F5.2 [Sun] [Ca/Fe] ? Log Ca/Fe abundance 88- 91 F4.2 [Sun] [Ti/Fe] ? Log Ti/Fe abundance 93-111 A19 --- OName Other name(s) 113-114 A2 --- Ref Literature reference code; in refs.dat file -------------------------------------------------------------------------------- Byte-by-byte Description of file: refs.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 2 A2 --- Ref Reference identifier 4- 22 A19 --- BibCode Bibliographic code 24- 44 A21 --- Aut Author's name 46- 64 A19 --- Cat Catalog in the VizieR database -------------------------------------------------------------------------------- History: From electronic version of the journal ================================================================================ (End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 22-May-2015