J/A+A/459/423 VI and [Fe/H] of Fornax dSph RGB stars (Battaglia+, 2006)
The DART imaging and CaT survey of the Fornax dwarf spheroidal galaxy.
Battaglia G., Tolstoy E., Helmi A., Irwin M.J., Letarte B., Jablonka P.,
Hill V., Venn K.A., Shetrone M.D., Arimoto N., Primas F., Kaufer A.,
Francois P., Szeifert T., Abel T., Sadakane K.
<Astron. Astrophys. 459, 423 (2006)>
=2006A&A...459..423B 2006A&A...459..423B
ADC_Keywords: Galaxies, nearby ; Stars, giant ; Photometry ; Abundances, [Fe/H]
Keywords: galaxies: dwarf - galaxies: individual: Fornax -
galaxies: kinematics and dynamics - galaxies: stellar content -
galaxies: Local Group - stars: abundances
Description:
We present the results of the DART imaging and CaII triplet (CaT)
survey of the Fornax dwarf spheroidal galaxy (dSph) at ESO. We
collected hundreds of low resolution spectra of Red Giant Branch (RGB)
stars in the CaT region, using VLT/FLAMES in Medusa mode, with the
GIRAFFE spectrograph (grating LR8, resolving power R∼6500). We list
the results for the targets with a S/N per Angstrom >10 and an error
in velocity <5km/s, because we found this to be the minimum for an
accurate determination of velocity and equivalent width. We checked
the sample to weed out any spurious object (e.g., broken fibres,
background galaxies, foreground stars, spectra not consistent with
RGBs). We use a 2.5sigma cut from the system velocity to derive which
stars are probable velocity members of the Fornax dSph. We transform
the equivalent width of the CaT lines of probable velocity members
into metallicity ([Fe/H]) using the relation derived by Rutledge et
al. (1997PASP..109..907R 1997PASP..109..907R) and combining the CaT lines as in Tolstoy et
al. (2001MNRAS.327..918T 2001MNRAS.327..918T). The errors in [Fe/H] are based on S/N
computations and adjusted to agree with repeated measurements.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 94 640 Properties of VLT/FLAMES targets in Fornax dSph
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See also:
I/185 : The giant branch of the Fornax dwarf spheroidal galaxy (Sagar+, 1990)
J/AJ/127/840 : VRI photometry of Fornax red giants (Pont+, 2004)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Star Name (fnxNNNNN or ETNNNN)
15 I1 h RAh Right Ascension (J2000)
17- 18 I2 min RAm Right Ascension (J2000)
20- 24 F5.2 s RAs Right Ascension (J2000)
27 A1 --- DE- Declination sign (J2000)
28- 29 I2 deg DEd Declination (J2000)
31- 32 I2 arcmin DEm Declination (J2000)
34- 37 F4.1 arcsec DEs Declination (J2000)
40- 45 F6.3 mag Vmag V band magnitude
49- 53 F5.3 mag e_Vmag Error in V band magnitude
56- 61 F6.3 mag Imag I band magnitude
65- 69 F5.3 mag e_Imag Error in I band magnitude
72- 75 F4.1 --- S/N Signal-to-noise ratio per Angstrom
79- 83 F5.2 [Sun] [Fe/H] ?=99.99 Metallicity from CaII triplet
lines equivalent width (1)
88- 91 F4.2 [Sun] e_[Fe/H] ?=9.99 Error in [Fe/H] (1)
94 A1 --- Member [Y/N] Flag indicating membership (2)
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Note (1): Targets with no metallicity information have an assigned value
[Fe/H]=99.99 and e_[Fe/H]=9.99
Note (2): Membership flag as follows:
Y = Probable velocity member
N = Probable non-member
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Acknowledgements:
Giuseppina Battaglia, gbattagl(at)astro.rug.nl
(End) G. Battaglia [Kapteyn Astron. Inst.], P. Vannier [CDS] 28-Nov-2006