J/A+A/607/A44       FLAMES observations of NGC6535           (Bragaglia+, 2017)
NGC 6535: the lowest mass Milky Way globular cluster with a Na-O
anti-correlation? Cluster mass and age in the multiple population context.
    Bragaglia A., Carretta E., D'Orazi V., Sollima A., Donati P., Gratton R.G.,
    Lucatello S.
    <Astron. Astrophys. 607, A44 (2017)>
    =2017A&A...607A..44B        (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Abundances ; Spectroscopy

Keywords: stars: abundances - stars: atmospheres - stars: Population II -
          open clusters and associations: individual: NGC 6535 -
          globular clusters: general

Abstract:
    To understand globular clusters (GCs) we need to comprehend how their
    formation process was able to produce their abundance distribution of
    light elements. In particular, we need to figure out which stars
    imprinted the peculiar chemical signature of GCs. One of the best way
    is to study the light-element anti-correlations in a large sample of
    GCs, analysed homogeneously. As part of our spectroscopic survey of
    GCs with FLAMES, we present here the results of our study of about 30
    red giant member stars in the low-mass, low-metallicity Milky Way
    cluster NGC 6535. We measured its metallicity (finding [Fe/H]=-1.95,
    rms=0.04dex in our homogeneous scale) and other elements, in
    particular we concentrate here on O and Na abundances. These elements
    define the normal Na-O anti-correlation of classical GCs, making NGC
    6535 perhaps the lowest mass cluster with confirmed presence of
    multiple populations. We updated the census of Galactic and
    extragalactic GCs for which a statement on the presence or absence of
    multiple populations can be made on the basis of high-resolution
    spectroscopy preferentially, or photometry and low-resolution
    spectroscopy otherwise, discussing the importance of mass and age of
    the clusters.

Description:
    We used FLAMES@VLT spectra of 45 stars in the globular cluster NGC
    6535 to measure radial velocity and infer cluster membership, to
    derive atmospheric parameters and abundances (in particular of the
    light elements O and Na). We find a O-Na anticorrelation, as normal
    for a GC. We also compile a list of clusters known to host (or not)
    multiple populations on the basis of their chemistry.

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table2.dat        91       45   Basic information on observed stars


See also:
   J/AJ/121/916 : HST obs. of NGC 2298, 5897, 6535, and 6626 (Testa+, 2001)


Byte-by-byte Description of file: table2.dat

   Bytes Format Units   Label     Explanations

   1-  7  A7    ---     ID        Star ID (from Testa et al., 2001,
                                   Cat. J/AJ/121/916)
       9  A1    ---     Instr     UVES (U) or GIRAFFE (G) spectrum acquired
  11- 12  I2    h       RAh       Right ascension (J2000.0)
  14- 15  I2    min     RAm       Right ascension (J2000.0)
  17- 21  F5.2  s       RAs       Right ascension (J2000.0)
      23  A1    ---     DE-       Declination sign (J2000.0)
  24- 25  I2    deg     DEd       Declination (J2000.0)
  27- 28  I2    arcmin  DEm       Declination (J2000.0)
  30- 34  F5.2  arcsec  DEs       Declination (J2000.0)
  36- 41  F6.3  mag     Vmag      V magnitude
  43- 47  F5.3  mag     V-I       (V-I) colour index
  49- 54  F6.3  mag     Ksmag     ?=0 2MASS Ks magnitude
  56- 61  F6.2  km/s    HRV       Heliocentric radial velocity
  63- 66  F4.2  km/s    e_HRV     Error on HRV
  68- 70  A3    ---     Memb      Membership flag (M/NM?/NM)
  72- 87  A16   ---     2MASS     2MASS identification
  89- 91  A3    ---     q_2MASS   2MASS quality flag for JHK


Acknowledgements:
    Angela Bragaglia, angela.bragaglia(at)oabo.inaf.it
(End)                                        Patricia Vannier [CDS]  02-Aug-2017