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J/AJ/136/1039     CaII index of SMC red giant branch stars      (Carrera+, 2008)

The chemical enrichment history of the Small Magellanic Cloud and its gradients. Carrera R., Gallart C., Aparicio A., Costa E., Mendez R.A., Noel N.E.D. <Astron. J., 136, 1039-1048 (2008)> =2008AJ....136.1039C
ADC_Keywords: Magellanic Clouds ; Stars, giant ; Spectra, infrared ; Radial velocities ; Photometry, VRI Keywords: galaxies: evolution - galaxies: individual (SMC) - galaxies: stellar content - Local Group - Magellanic Clouds Abstract: We present stellar metallicities derived from Ca II triplet spectroscopy in over 350 red giant branch stars in 13 fields distributed in different positions in the Small Magellanic Cloud, ranging from ∼1° to ∼4° from its center. In the innermost fields, the average metallicity is [Fe/H]~-1. This value decreases when we move away toward outermost regions. This is the first detection of a spectroscopic metallicity gradient in this galaxy. We show that the metallicity gradient is related to an age gradient, in the sense that more metal-rich stars, which are also younger, are concentrated in the central regions of the galaxy. Description: The spectroscopic observations were carried on in service mode with the VLT Antu telescope, at Paranal Observatory (Chile), through program 074.B-0446. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 67 372 Red giants stars observed
See also: J/AJ/131/2514 : Radial velocities of red giants in the SMC (Harris+, 2006) J/AJ/135/836 : Calcium triplet index in LMC stars (Carrera+, 2008) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 2 I2 h RAh Hour of Right Ascension (J2000) 4- 5 I2 min RAm Minute of Right Ascension (J2000) 7- 10 F4.1 s RAs Second of Right Ascension (J2000) 12 A1 --- DE- Sign of the Declination (J2000) 13- 14 I2 deg DEd Degree of Declination (J2000) 16- 17 I2 arcmin DEm Arcminute of Declination (J2000) 19- 22 F4.1 arcsec DEs Arcsecond of Declination (J2000) 24- 28 F5.2 0.1nm W.CaT The CaT index (1) 30- 33 F4.2 0.1nm e_W.CaT The 1σ uncertainty in W.CaT 35- 39 F5.2 mag Vmag ?=99.99 The V band magnitude 41- 45 F5.2 mag Imag ?=99.99 The I band magnitude 47- 52 F6.1 km/s RV Radial velocity 54- 57 F4.1 km/s e_RV The 1σ uncertainty in RV 59- 67 A9 --- Comm Additional comment ("AGB", "AGB?" or "No member")
Note (1): Defined as ΣCa, the sum of the equivalent widths of the three CaT lines (848.4-868.2nm). The metallicity is given by: [Fe/H] =-2.95+0.3ΣCa+0.23MI, where MI is the absolute I magnitude, and [Fe/H] is in the Carretta & Gratton scale (1997, Cat. J/A+AS/121/95) metallicity scale.
Nomenclature Note: Sources identified as <[CGA2008] JHHMMSS.s+DDMMSS.s> in Simbad History: From electronic version of the journal References: Noel et al., Paper I 2007AJ....133.2037N Carrera et al., Paper II 2007AJ....134.1298C, Cat. J/AJ/134/1298 Carrera et al., Paper III 2008AJ....135..836C, Cat. J/AJ/135/836
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 06-Apr-2011
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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