J/MNRAS/396/1895 MgI and sTiO index definitions (Cenarro+, 2009)
Mg and TiO spectral features at the near-IR: spectrophotometric index
definitions and empirical calibrations.
Cenarro A.J., Cardiel N., Vazdekis A., Gorgas J.
<Mon. Not. R. Astron. Soc., 396, 1895-1914 (2009)>
=2009MNRAS.396.1895C 2009MNRAS.396.1895C
ADC_Keywords: Clusters, globular ; Spectroscopy
Keywords: stars: abundances - stars: fundamental parameters -
globular clusters: general - galaxies: stellar content
Abstract:
Using the near-infrared spectral stellar library of Cenarro et al.
(J/MNRAS/326/959), the behaviour of the MgI line at 8807Å and
nearby TiO bands is analyzed in terms of the effective temperature,
surface gravity and metallicity of the library stars. New
spectroscopic indices for both spectral features - namely MgI and sTiO
- are defined, and their sensitivities to different signal-to-noise
ratios, spectral resolutions, flux calibrations and sky emission-line
residuals are characterized. The two new indices exhibit interesting
properties. In particular, MgI is a good indicator of the Mg
abundance, whereas sTiO is a powerful dwarf-to-giant discriminator for
cold spectral types. Empirical fitting polynomials that reproduce the
strength of the new indices as a function of the stellar atmospheric
parameters are computed, and a fortran routine with the fitting
function predictions is made available. A thorough study of several
error sources, non-solar [Mg/Fe] ratios and their influence on the
fitting function residuals is also presented. From this analysis, an
[Mg/Fe] underabundance of ~-0.04 is derived for the Galactic open
cluster M67.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 96 5 Definition of previous and new indices for the
near-IR MgI line (λ 8807Å) and
TiO bands (λλ 8432, 8442, 8452Å;
λλ 8860, 8868Å)
table10.dat 103 706 *MgI and sTiO index measurements
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Note on table10.dat: Additional information for the library stars (e.g.
atmospheric parameters, [Ca/Fe] abundances, CaT, PaT, and CaT* index values,
their errors and fitting function residuals, B and V apparent magnitudes,
signal-to-noise ratios per angstrom, and other names) can be found at
Cenarro et al., (2001, Cat. J/MNRAS, 326, 959 and 2001MNRAS.326..981C 2001MNRAS.326..981C)
and at http://www.ucm.es/info/Astrof/ellipt/MgIsTiO.html
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See also:
J/MNRAS/326/959 : Near-IR Ca triplet empirical calibration (Cenarro+ 2001)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Index Index name
6- 8 A3 --- Ref Reference code (1)
10- 12 A3 --- Type Type (2)
14- 26 A13 0.1nm lambda Central bandpass
28- 40 A13 0.1nm lambdaCont1 Continuum bandpass
42- 54 A13 0.1nm lambdaCont2 Continuum bandpass
56- 68 A13 0.1nm lambdaCont3 Continuum bandpass
70- 82 A13 0.1nm lambdaCont4 Continuum bandpass
84- 96 A13 0.1nm lambdaCont5 Continuum bandpass
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Note (1): Codes for the references are as follow:
CVP = Carter et al., 1986ApJ...311..637C 1986ApJ...311..637C
DTT = Diaz et al. 1989MNRAS.239..325D 1989MNRAS.239..325D
TW = this work
Note (2): Types as follows:
c-a = classical-atomic index
c-m = classical-molecular index
g-s = generic-atomic and generic-slope-like indices
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Byte-by-byte Description of file: table10.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq Sequential number
5- 18 A14 --- Name Star name
20- 21 I2 h RAh Right ascension (J2000)
23- 24 I2 min RAm Right ascension (J2000)
26- 29 F4.1 s RAs Right ascension (J2000)
31 A1 --- DE- Declination sign (J2000)
32- 33 I2 deg DEd Declination (J2000)
35- 36 I2 arcmin DEm Declination (J2000)
38- 39 I2 arcsec DEs Declination (J2000)
40 A1 --- r [*S] Remark on the position (1)
42- 54 A13 --- SpType MK spectral type
57- 62 F6.3 0.1nm MgI MgI index measurement
64- 68 F5.3 0.1nm e_MgI rms uncertainty on MgI (2)
70- 75 F6.3 0.1nm dMgI ? Fitting function residual for MgI
77- 81 F5.3 0.1nm sTiO sTiO index measurement
83- 87 F5.3 0.1nm e_sTiO rms uncertainty on sTiO (2)
89- 94 F6.3 0.1nm dsTiO ? Fitting function residual for IsTiO
96-101 F6.3 [-] [Mg/Fe] ? [Mg/Fe] abundances (when available)
103 I1 --- r_[Mg/Fe] ? Reference for [Mg/Fe] (3)
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Note (1): Note on position as follows:
* = original position in B1950, transformed into J2000 by CDS
S = position from Simbad Database
Note (2): accounting for photon noise and typical uncertainties
in radial velocity
Note (3): Sources for [Mg/Fe] values as follows:
1 = the catalogue of spectroscopic abundances in stars
(Borkova & Marsakov, 2005, Cat. J/AZh/82/453)
2 = the catalogue of chemical abundances in late-type stars
(Thevenin 1998, Cat. III/193) corrected to the
Borkova & Marsakov (2005, Cat. J/AZh/82/453) system
3 = Pilachowski, Sneden & Kraft (1996AJ....111.1689P 1996AJ....111.1689P)
4 = Gratton & Sneden (1987A&A...178..179G 1987A&A...178..179G)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 01-Apr-2011