J/A+A/635/A114 EW and [Fe/H] for 30000 globular cluster RGB stars (Husser+ 2020)
A stellar census in globular clusters with MUSE. Extending the CaT-metallicity
relation below the horizontal branch and applying it to multiple populations.
Husser T.-O., Latour M., Brinchmann J., Dreizler S., Giesers B.,
Goettgens F., Kamann S., Roth M.M., Weilbacher P.M., Wendt M.
<Astron. Astrophys. 635, A114 (2020)>
=2020A&A...635A.114H 2020A&A...635A.114H (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Stars, giant ; Abundances, [Fe/H] ;
Equivalent widths
Keywords: methods: data analysis - methods: observational -
techniques: imaging spectroscopy - stars: abundances -
globular clusters: general
Abstract:
The CaII triplet in the near-infrared at 8498, 8542, and 8662Å is
visible in stars with spectral types between F and M and can be used
to determine their metallicities. We calibrated the relation using
average cluster metallicities from literature and MUSE spectra, and
extend it below the horizontal branch - a cutoff that has
traditionally been made to avoid a non-linear relation - using a
quadratic function. In addition to the classic relation based on
V-\vhb$ we used calibrations based on absolute magnitude and
luminosity and used it for those cluster, for which no HB brightness
was available. The obtained relations are then used to calculate
metallicities for all the stars in the sample.
Description:
We measured equivalent widths of >30000 red giant branch stars in 25
globular clusters from our large MUSE survey and used mean cluster
metallicities to calibrate the CaT-metallicity relation, from which
reduced equivalent widths and metallicities were calculated for all
stars. Metallicities are given for four different calibrations, based
on the classical linear relation with only stars brighter than the HB
(1), all RGB stars and a quadratic relation (2), and two calibrations
based on absolute magnitude (3) and luminosity (4). All metallicities
are derived on the scale defined by Dias et al. (2016A&A...590A...9D 2016A&A...590A...9D).
The star IDs are taken from the ACS Survey of Galactic Globular
Clusters (Anderson et al., 2008AJ....135.2055A 2008AJ....135.2055A), if they exist in that
catalog.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
musecat.dat 591 30182 Measured equivalent widths of >30000 red giant
branch stars in 25 globular clusters (table 8)
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See also:
J/AJ/133/1658 : ACS survey of galactic globular clusters (Sarajedini+, 2007)
Byte-by-byte Description of file: musecat.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Cluster Name of globular cluster (NGC NNNN)
10- 16 I7 --- Id Unique ID of star within its cluster
18- 28 F11.7 deg RAdeg Right ascension (J2000)
30- 40 F11.7 deg DEdeg Declination (J2000)
42- 66 F25.17 0.1nm EW1 EW of 1st CaT line from Voigt profile fit
68- 96 F29.18 0.1nm e_EW1 Uncertainty for EW of 1st line
98-116 F19.17 0.1nm EW2 EW of 2nd CaT line from Voigt profile fit
118-138 F21.18 0.1nm e_EW2 Uncertainty for EW of 2nd line
140-158 F19.17 0.1nm EW3 EW of 3rd CaT line from Voigt profile fit
160-180 F21.18 0.1nm e_EW3 Uncertainty for EW of 3rd line
182-203 E22.17 0.1nm EW1int EW of 1st CaT line from integration
205-225 F21.18 0.1nm EW2int EW of 2nd CaT line from integration
227-248 F22.19 0.1nm EW3int EW of 3rd CaT line from integration
250-267 F18.16 --- REW1 ? Derived reduced EW from linear relation
with stars brighter than HB
269-288 F20.18 --- e_REW1 ? Uncertainty for reduced EW
290-311 F22.19 [Sun] [Fe/H]1 ? Derived metallicity from linear relation
with stars brighter than HB
313-331 F19.17 [Sun] e_[Fe/H]1 ? Uncertainty for metallicity
333-351 F19.16 --- REW2 ? Derived reduced EW from quadratic relation
with all RGB stars
353-373 F21.18 --- e_REW2 ? Uncertainty for reduced EW
375-397 F23.20 [Sun] [Fe/H]2 ? Derived metallicity from quadratic
relation with all RGB stars
399-418 F20.17 [Sun] e_[Fe/H]2 ? Uncertainty for metallicity
420-438 F19.16 --- REW3 ? Derived reduced EW from calibration based
on absolute magnitude
440-460 F21.18 --- e_REW3 ? Uncertainty for reduced EW
462-484 E23.19 [Sun] [Fe/H]3 ? Derived metallicity from calibration based
on absolute magnitude
486-505 F20.17 [Sun] e_[Fe/H]3 ? Uncertainty for metallicity
507-525 F19.16 --- REW4 ? Derived reduced EW from calibration based
on luminosity
527-547 F21.18 --- e_REW4 ? Uncertainty for reduced EW
549-570 E22.17 [Sun] [Fe/H]4 ? Derived metallicity from calibration based
on luminosity
572-591 F20.17 [Sun] e_[Fe/H]4 ? Uncertainty for metallicity
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Acknowledgements:
Tim-Oliver Husser, thusser(at)uni-goettingen.de
(End) Patricia Vannier [CDS] 05-Feb-2020