J/AJ/127/840 VRI photometry of Fornax red giants (Pont+, 2004)
The chemical enrichment history of the Fornax dwarf spheroidal galaxy from the
infrared calcium triplet.
Pont F., Zinn R., Gallart C., Hardy E., Winnick R.
<Astron. J., 127, 840-860 (2004)>
=2004AJ....127..840P 2004AJ....127..840P
ADC_Keywords: Stars, giant ; Photometry ; Abundances, [Fe/H] ; Equivalent widths
Keywords: galaxies: abundances - galaxies: individual (Fornax) - Local Group -
stars: abundances
Abstract:
Near-infrared spectra were obtained for 117 red giants in the Fornax
dwarf spheroidal galaxy with the FORS1 spectrograph on the VLT, in
order to study the metallicity distribution of the stars and to lift
the age-metallicity degeneracy of the red giant branch (RGB) in the
color-magnitude diagram (CMD). Metallicities are derived from the
equivalent widths of the infrared calcium triplet lines at 8498, 8542,
and 8662Å calibrated with data from globular clusters, the open
cluster M67, and the LMC. For a substantial portion of the sample, the
strength of the calcium triplet is unexpectedly high, clearly
indicating that the main stellar population of Fornax is significantly
more metal-rich than could be inferred from the position of its RGB in
the CMD.
Description:
The observations were obtained on the night of 1999 December 1, using
the FORS1 instrument installed on the Cassegrain focus of the UT1
telescope (first 8.2m unit of the ESO Very Large Telescope) at
Paranal, Chile.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 100 118 Fornax star data
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See also:
I/185/ : Giant branch of Fornax dwarf spheroidal galaxy (Sagar+, 1990)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- [PZG2004] Object identification number
5 I1 h RAh Hour of Right Ascension (J2000)
7- 8 I2 min RAm Minute of Right Ascension (J2000)
10- 14 F5.2 s RAs Second of Right Ascension (J2000)
16 A1 --- DE- Sign of the Declination (J2000)
17- 18 I2 deg DEd Degree of Declination (J2000)
20- 21 I2 arcmin DEm Arcminute of Declination (J2000)
23- 27 F5.2 arcsec DEs Arcsecond of Declination (J2000)
29- 34 F6.3 mag Vmag ? The V band magnitude (1)
36- 40 F5.3 mag e_Vmag ? The 1σ error in Vmag (1)
42- 47 F6.3 mag Rcmag ? The Cousins R band magnitude (1)
49- 53 F5.3 mag e_Rcmag ? The 1σ error in Rcmag (1)
55- 60 F6.3 mag Icmag The Cousins I band magnitude (1)
61 A1 --- u_Icmag Uncertainty flag on Imag
63- 67 F5.3 mag e_Icmag ? The 1σ error in Icmag (1)
69- 73 F5.3 mag V-Ic ? The (V-Ic) color (1)
75- 78 F4.2 0.1nm CaEW ? Weighted sum of the Ca widths (2)
80- 83 F4.2 0.1nm e_CaEW ? The 1σ error in CaEW
85- 89 F5.2 [Sun] [Fe/H] ? Metallicity
90 A1 --- u_[Fe/H] Uncertainty flag on [Fe/H]
92- 95 F4.2 [Sun] e_[Fe/H] ? The 1σ error in [Fe/H]
97- 99 A3 --- n_[PZG2004] Additional notes on [PZG2004] (3)
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Note (1): Photometry from Gallart et al. (in prep.).
Note (2): Where CaEW = 0.5w1 + w2 + 0.6w3, where w1, w2 and w3 are the
equivalent widths of individual Calcium lines (λ 8498, 8542,
8662 Angstroms, respectively).
Note (3): Notes are numbered as follows:
1 = suspected non-member from radial velocity
2 = visible double
3 = no second spectrum
4 = second spectrum truncated
5 = large dip in the spectrum at 8680Å
6 = faint visible companion
7 = sky noise >7%
g = equivalent width from Gaussian fit
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 02-Jul-2004