J/ApJ/801/69 Iron EWs for 21 giant star members of NGC3201 (Mucciarelli+, 2015)
The origin of the spurious iron spread in the globular cluster NGC 3201.
Mucciarelli A., Lapenna E., Massari D., Ferraro F.R., Lanzoni B.
<Astrophys. J., 801, 69 (2015)>
=2015ApJ...801...69M 2015ApJ...801...69M
ADC_Keywords: Equivalent widths ; Abundances, [Fe/H] ; Radial velocities ;
Stars, giant ; Clusters, globular
Keywords: globular clusters: individual: NGC 3201;
stars: abundances; techniques: spectroscopic
Abstract:
NGC 3201 is a globular cluster suspected to have an intrinsic spread
in the iron content. We re-analyzed a sample of 21 cluster stars
observed with UVES-FLAMES at the Very Large Telescope and for which
Simmerer et al. (2013ApJ...764L...7S 2013ApJ...764L...7S) found a 0.4dex wide [Fe/H]
distribution with a metal-poor tail. We confirmed that when
spectroscopic gravities are adopted, the derived [Fe/H] distribution
spans ∼0.4dex. On the other hand, when photometric gravities are used,
the metallicity distribution from Fe I lines remains large, while that
derived from Fe II lines is narrow and compatible with no iron spread.
We demonstrate that the metal-poor component claimed by Simmerer et
al. (2013ApJ...764L...7S 2013ApJ...764L...7S) is composed by asymptotic giant branch stars
that could be affected by non-local thermodynamical equilibrium
effects driven by iron overionization. This leads to a decrease of the
Fe I abundance, while leaving the Fe II abundance unaltered. A similar
finding has been already found in asymptotic giant branch stars of the
globular clusters M5 and 47 Tucanae. We conclude that NGC 3201 is a
normal cluster, with no evidence of intrinsic iron spread.
Description:
High-resolution spectra taken with UVES-FLAMES at VLT for 21 giant
stars members of NGC 3201 have been retrieved from the ESO archive
(R∼45000 and coverage∼4800-6800Å).
Spectroscopic targets have been identified in our photometric catalog,
obtained by combining high-resolution images acquired with the Hubble
Space Telescope/Advanced Camera for Surveys (ACS) camera and
wide-field images acquired with the ESO-WFI imager. Both the
photometric data sets have been obtained through the V and I filters.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 86 21 Main information of the target stars
table2.dat 37 3244 Star identification number, wavelength,
oscillator strength, excitation potential and
measured EWs for all the used transitions
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See also:
B/eso : ESO Science Archive Catalog (ESO, 1991-2015)
B/hst : HST Archived Exposures Catalog (STScI, 2007)
J/ApJ/780/94 : Abundances of red giants in 47 Tuc (Cordero+, 2014)
J/A+A/527/A18 : EW of 6 subgiants of ω Cen (Pancino+, 2011)
J/ApJ/726/L20 : Spectroscopy of Terzan 5 (Origlia+, 2011)
J/ApJ/722/1373 : ω Centauri giants abundances (Johnson+, 2010)
J/A+A/517/A81 : 2nd & 3d param. of HB of globular clusters (Gratton+, 2010)
J/A+A/505/139 : Abundances of red giants in 17 GCs (Carretta+, 2009)
J/MNRAS/383/183 : CaII triplet of RGB from VLT/FLAMES obs. (Battaglia+, 2008)
J/AJ/134/1298 : CaII EWs in 29 Galactic clusters (Carrera+, 2007)
J/ApJS/161/304 : Star clusters in the MW and satellites (McLaughlin+, 2005)
J/AJ/130/2140 : Abundances & velocities in globular clusters (Pritzl+, 2005)
J/A+A/416/1117 : Abundances in the early Galaxy (Cayrel+, 2004)
J/PAZh/22/269 : Giant branch and variable stars in NGC 3201 (Samus+, 1996)
J/ApJS/90/83 : Binaries in NGC 3201 (Cote+, 1994)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- ID [63/374] Star identification number (G1)
5- 15 F11.7 deg RAdeg Right ascension in decimal degrees (J2000)
17- 27 F11.7 deg DEdeg Declination in decimal degrees (J2000)
29- 33 F5.2 mag Vmag [12.6/14] V-band magnitude
35- 39 F5.2 mag Imag [11/12.6] I-band magnitude
41- 45 F5.1 km/s HRV [487/500] Heliocentric radial velocity
47- 49 F3.1 km/s e_HRV [0.2/1] HRV uncertainty
51- 54 I4 K Teff [4330/4920] Effective temperature
56- 59 F4.2 [cm/s2] logg [0.8/1.7] Surface gravity
61- 64 F4.2 km/s Vt [1.4/1.9] Microturbulent velocity
66- 70 F5.2 [Sun] [FeI/H] [-1.7/-1.2] FeI metallicity (1)
72- 75 F4.2 [Sun] e_[FeI/H] [0.02/0.05] [FeI/H] uncertainty
77- 81 F5.2 [Sun] [FeII/H] [-1.5/-1.2] FeII metallicity (1)
83- 86 F4.2 [Sun] e_[FeII/H] [0.03/0.06] [FeII/H] uncertainty
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Note (1): [FeI/H] and [FeII/H] have been obtained adopting photometric
gravities. <[FeI/H]≥-1.46±0.02 and <[FeII/H]≥-1.40±0.01
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- ID [63/374] Star identification number (G1)
5- 12 F8.3 0.1nm lambda [4791/6753] Wavelength λ
14- 17 A4 --- Ion Ion identification (FeI or FeII)
19- 24 F6.3 [-] log(gf) [-6.2/0.7] Log of the oscillator strength
26- 30 F5.3 eV ExPot [0.05/5] Excitation potential
32- 36 F5.1 0.1pm EW [12/132] Equivalent width in mÅ
37 A1 --- --- [0]
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Global notes:
Note (G1):
Same identification numbers used by Simmerer et al. (2013ApJ...764L...7S 2013ApJ...764L...7S)
who adopted the original names by Cote et al. (1994, J/ApJS/90/83;
<CL* NGC 3201 CWFD 3-NNN> in Simbad).
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 15-Jul-2015