J/A+A/631/A14 NGC 2808 stellar population spectra (Latour+, 2019)
A stellar census in globular clusters with MUSE:
multiple populations chemistry in NGC 2808.
Latour M., Husser T.-O., Giesers B., Kamann S., Goettgens F., Dreizler S.,
Brinchmann J., Bastian N., Wendt M., Weilbacher P.M., Molinski N.S.
<Astron. Astrophys. 631, A14 (2019)>
=2019A&A...631A..14L 2019A&A...631A..14L (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Populations, stellar ; Spectroscopy
Keywords: techniques: imaging spectroscopy - stars: abundances -
globular clusters: individual: NGC 2808
Abstract:
Galactic globular clusters (GCs) are now known to host multiple
populations displaying particular abundance variations. The different
populations within a GC can be well distinguished following their
position in the pseudo two-colors diagrams, also referred to as
"chromosome maps". These maps are constructed using optical and
near-UV photometry available from the Hubble Space Telescope (HST) UV
survey of GCs. However, the chemical tagging of the various
populations in the chromosome maps is hampered by the fact that HST
photometry and elemental abundances are both available only for a
limited number of stars. The spectra collected as part of the MUSE
survey of globular clusters provide a spectroscopic counterpart to the
HST photometric catalogs covering the central regions of GCs. In this
paper, we use the MUSE spectra of 1155 red giant branch (RGB) stars in
NGC 2808 to characterize the abundance variations seen in the multiple
populations of this cluster. We use the chromosome map of NGC 2808 to
divide the RGB stars into their respective populations. We then
combine the spectra of all stars belonging to a given population,
resulting in one high signal-to-noise ratio spectrum representative of
each population. Variations in the spectral lines of O, Na, Mg, and Al
are clearly detected among four of the populations. In order to
quantify these variations, we measured equivalent width differences
and created synthetic populations spectra that were used to determine
abundance variations with respect to the primordial population of the
cluster. Our results are in good agreement with the values expected
from previous studies based on high-resolution spectroscopy. We do not
see any significant variations in the spectral lines of Ca, K, and Ba.
We also do not detect abundance variations among the stars belonging
to the primordial population of NGC 2808.
Description:
We provide the summed spectra of population 1 to 4. The radial
velocities are corrected so that the spectrum are at rest wavelength.
The table includes the list of stars whose spectrum are included in
the combined spectra along with their population number.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table.dat 32 1115 Star ID and population
list.dat 81 4 List of summed spectra
fits/* . 4 Individual summed spectra
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See also:
J/A+A/413/343 : RGB stars in NGC 2808 (Cacciari+, 2004)
J/A+A/480/397 : XMM observations of NGC 2808 and NGC 4372 (Servillat+, 2008)
J/A+A/490/641 : X-ray sources toward NGC 2808 (Servillat+, 2008)
J/A+A/528/A127 : Radial velocities in NGC 2808 (Moni Bidin+, 2011)
J/A+A/534/A123 : Horizontal branch stars in NGC 2808 (Gratton+, 2011)
J/A+A/542/A129 : NGC 2808 central kinematics (Luetzgendorf+, 2012)
J/MNRAS/437/1609 : NGC 2808 HB stars abundances (Marino+, 2014)
J/ApJ/810/148 : Red giant abundances in NGC 2808 (Carretta, 2015)
J/A+A/586/A51 : JK photometry of NGC 2808 (Massari+, 2016)
J/A+A/592/A66 : NGC 2808 AGB and RGB stars Na abundance (Wang+, 2016)
J/A+A/615/A17 : Red giant Aluminium abundances in NGC 2808 (Carretta+, 2018)
Byte-by-byte Description of file: table.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- ID ID from the ACS Survey of
Galactic Globular Clusters (1)
8 I1 --- Pop [1/4] Population number of the star
10- 20 F11.7 deg RAdeg Right ascension (J2000) (1)
22- 32 F11.7 deg DEdeg Declination (J2000) (1)
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Note (1): From https://archive.stsci.edu/prepds/acsggct/
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Nx Number of pixels along X-axis
6- 9 I4 0.1nm bAWAV Lower value of wavelength interval
11- 17 F7.2 0.1nm BAWAV Upper value of wavelength interval
19- 22 F4.2 0.1nm dAWAV Wavelength resolution
24- 26 I3 Kibyte size Size of FITS file
28- 53 A26 --- FileName Name of FITS file, in subdirectory fits
55- 81 A27 --- Title Title of the FITS file
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Acknowledgements:
Marilyn Latour, marilyn.latour(at)uni-goettingen.de
(End) Patricia Vannier [CDS] 07-Oct-2019