J/ApJ/810/76 Grid of red giant synthetic spectra with 0<[M/H]≤-6 (Short+, 2015)
NLTE and LTE Lick indices for red giants from [Fe/H] 0.0 to -6.0 at SDSS
and IDS spectral resolution.
Short C.I., Young M.E., Layden N.
<Astrophys. J., 810, 76 (2015)>
=2015ApJ...810...76S 2015ApJ...810...76S (SIMBAD/NED BibCode)
ADC_Keywords: Abundances ; Stars, giant ; Models
Keywords: stars: atmospheres; stars: fundamental parameters; stars: late-type
Abstract:
We investigate the dependence of the complete system of 22 Lick
indices on overall metallicity scaled from solar abundances, [M/H],
from the solar value, 0.0, down to the extremely metal-poor (XMP)
value of -6.0, for late-type giant stars (MK luminosity class III,
logg=2.0) of MK spectral class late-K to late-F (3750<Teff<6500K) of
the type that are detected as "fossils" of early galaxy formation in
the Galactic halo and in extra-galactic structures. Our investigation
is based on synthetic index values, I, derived from atmospheric models
and synthetic spectra computed with PHOENIX in Local Thermodynamic
Equilibrium (LTE) and Non-LTE (NLTE), where the synthetic spectra have
been convolved to the spectral resolution, R, of both IDS and SDSS
(and LAMOST) spectroscopy. We identify nine indices, that we designate
"Lick-XMP", that remain both detectable and significantly
[M/H]-dependent down to [M/H] values of at least ~-5.0, and down to
[M/H]~-6.0 in five cases, while also remaining well-behaved
(single-valued as a function of [M/H] and positive in linear units).
For these nine indices, we study the dependence of I on NLTE effects,
and on spectral resolution. For our LTE I values for spectra of SDSS
resolution, we present the fitted polynomial coefficients, Cn, from
multi-variate linear regression for I with terms up to third order in
the independent variable pairs (Teff, [M/H]) and (V-K, [M/H]), and
compare them to the fitted Cn values of Worthey et al. (1994,
J/ApJS/94/687) at IDS spectral resolution.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table6.dat 93 324 LTE Partial I derivatives with respect to Teff and
[M], at each grid value of Teff and [M/H], in index
units and in units of σ for SDSS spectral
resolution for our nine H Lick-XMP indices
table7.dat 93 324 LTE Partial I derivatives with respect to V-K and
[M/H], at each grid value of V-K
for [M/H]=0.0 models and [M/H], in index
units and in units of σ for SDSS spectral
resolution for our nine H Lick-XMP indices
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See also:
J/MNRAS/435/3667 : Equivalent widths of 6 NGC5694 stars (Mucciarelli+, 2013)
J/ApJ/778/56 : Hamburg/ESO Survey extremely metal-poor stars (Cohen+, 2013)
J/MNRAS/429/126 : Atmospheric parameters from Fe lines (Ruchti+, 2013)
J/AJ/145/13 : Metal-poor stars from SDSS/SEGUE I. Abundances (Aoki+, 2013)
J/A+A/549/A129 : Equivalent widths of cool stars (Cesetti+, 2013)
J/ApJ/751/156 : Ti and Fe lines in red supergiants (Bergemann+, 2012)
J/ApJS/111/377 : Hγ + Hδ absorption features (Worthey+ 1997)
J/ApJS/94/687 : Old stellar populations. V. (Worthey+, 1994)
J/AJ/103/1987 : Stars of very low metal abundance (Beers+ 1992)
Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1 I1 --- Type [1/4] Partial derivative description (1)
3- 8 A6 --- Index Lick-XMP index (Fe4383, Fe4531, Fe5015, Fe5270,
Fe5335, Fe5406, Mg b, Mg1 and Na D)
10- 13 F4.1 [-] Z [-6/-0] Model metallicity
15- 21 F7.4 --- T6500 [-0.8/2] Type value at Z and
model temperature 6500K
23- 29 F7.4 --- T6000 [-0.7/2.3] Type value at Z and
model temperature 6000K
31- 37 F7.4 --- T5500 [-0.6/2.6] Type value at Z and
model temperature 5500K
39- 45 F7.4 --- T5250 [-0.6/2.7] Type value at Z and
model temperature 5250K
47- 53 F7.4 --- T5000 [-0.5/2.9] Type value at Z and
model temperature 5000K
55- 61 F7.4 --- T4750 [-0.5/3] Type value at Z and
model temperature 4750K
63- 69 F7.4 --- T4500 [-0.5/3.2] Type value at Z and
model temperature 4500K
71- 77 F7.4 --- T4250 [-0.6/3.4] Type value at Z and
model temperature 4250K
79- 85 F7.4 --- T4000 [-0.7/3.6] Type value at Z and
model temperature 4000K
87- 93 F7.4 --- T3750 [-1/3.8] Type value at Z and
model temperature 3750K
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Note (1): Partial derivative description as follows:
1 = 100K * ∂I/∂Teff|[M/H];
2 = 100K * ∂I/∂Teff|[M/H]/σ;
3 = 0.5 * ∂I/∂[M/H]|Teff;
4 = 0.5 * ∂I/∂[M/H]|Teff/σ.
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Byte-by-byte Description of file: table7.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 I1 --- Type [1/4] Partial derivative description (1)
3- 8 A6 --- Index Lick-XMP index (Fe4383, Fe4531, Fe5015, Fe5270,
Fe5335, Fe5406, Mg b, Mg1 and Na D)
10- 13 F4.1 [-] Z [-6/-0] Model metallicity
15- 21 F7.4 --- C0.887 [-5.7/2.6] Type value at Z and
model (V-K)=0.887mag
23- 29 F7.4 --- C1.211 Type value at Z and model (V-K)=1.211mag
31- 37 F7.4 --- C1.578 Type value at Z and model (V-K)=1.578mag
39- 45 F7.4 --- C1.792 Type value at Z and model (V-K)=1.792mag
47- 53 F7.4 --- C2.017 Type value at Z and model (V-K)=2.017mag
55- 61 F7.4 --- C2.290 Type value at Z and model (V-K)=2.290mag
63- 69 F7.4 --- C2.585 Type value at Z and model (V-K)=2.585mag
71- 77 F7.4 --- C2.966 Type value at Z and model (V-K)=2.966mag
79- 85 F7.4 --- C3.475 Type value at Z and model (V-K)=3.475mag
87- 93 F7.4 --- C4.329 [-0.9/2.5] Type value at Z and
model (V-K)=4.329mag
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Note (1): Note that V-K is [M/H]-dependent and the V-K values used to label
the columns are only valid for [M/H] = 0.0 (Fig. 4 gives an
indication of the [M/H]-dependence on V-K).
Partial derivative description as follows:
1 = 0.25mag * ∂I/∂(V-K)|[M/H];
2 = 0.25mag * ∂I/∂(V-K)|[M/H]/σ;
3 = 0.5 * ∂I/∂[M/H]|(V-K);
4 = 0.5 * ∂I/∂[M/H]|(V-K)/σ;
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 16-Dec-2015