J/ApJS/171/146 Population synthesis in the blue. IV (Schiavon+, 2007)
Population synthesis in the blue.
IV. Accurate model predictions for Lick indices and UBV colors in single
stellar populations.
Schiavon R.P.
<Astrophys. J. Suppl. Ser., 171, 146-205 (2007)>
=2007ApJS..171..146S 2007ApJS..171..146S
ADC_Keywords: Abundances ; Clusters, globular ; Magnitudes ;
Models, evolutionary ; Spectroscopy
Keywords: galaxies: abundances - galaxies: elliptical and lenticular, cD -
galaxies: evolution - galaxies: stellar content -
globular clusters: general - stars: fundamental parameters
Abstract:
We present a new set of model predictions for 16 Lick absorption line
indices from Hδ through Fe5335 and UBV colors for single stellar
populations with ages ranging between 1 and 15Gyr, [Fe/H] ranging
from -1.3 to +0.3, and variable abundance ratios. The models are based
on accurate stellar parameters for the Jones library stars and a new
set of fitting functions describing the behavior of line indices as a
function of effective temperature, surface gravity, and iron
abundance. The abundances of several key elements in the library stars
have been obtained from the literature in order to characterize the
abundance pattern of the stellar library, thus allowing us to produce
model predictions for any set of abundance ratios desired. We develop
a method to estimate mean ages and abundances of iron, carbon,
nitrogen, magnesium, and calcium that explores the sensitivity of the
various indices modeled to those parameters. The models are compared
to high-S/N data for Galactic clusters spanning the range of ages,
metallicities, and abundance patterns of interest. Essentially all
line indices are matched when the known cluster parameters are adopted
as input. Comparing the models to high-quality data for galaxies in
the nearby universe, we reproduce previous results regarding the
enhancement of light elements and the spread in the mean
luminosity-weighted ages of early-type galaxies.
Description:
We adopted the library of stellar spectra by Jones (1999, Ph.D.
thesis, Univ. North Carolina). It consists of spectra of 684 stars
collected with the coude-feed telescope at Kitt Peak National
Observatory. The spectra cover the region that goes from 3820 to
5410Å with a gap between 4500 and 4780Å, with a resolution of
1.8Å.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table30.dat 159 623 Stars that make up the spectral library,
their atmospheric parameters, and Lick indices
measured in their spectra
table31.dat 138 158 Lick indices for single stellar populations:
the base models computed with solar-scaled
isochrones
table32.dat 138 134 Lick indices for single stellar populations:
the base models computed with α-enhanced
isochrones
table33.dat 49 195 Magnitudes computed using the solar-scaled
isochrones
table34.dat 49 165 Magnitudes computed using the α-enhanced
isochrones
table35.dat 138 120 Lick indices computed for the abundance pattern
of M67
table36.dat 138 120 Lick indices computed for the abundance pattern
of CN-strong stars in 47 Tuc, adopting the
solar-scaled Padova isochrones by Girardi et al.
(2000A&AS..141..371G 2000A&AS..141..371G), and a dwarf-poor IMF (x=-4)
table37.dat 138 120 Lick indices computed for the abundance pattern
of CN-weak stars in 47 Tuc, adopting the
solar-scaled Padova isochrones by Girardi et al.
(2000A&AS..141..371G 2000A&AS..141..371G), and a dwarf-poor IMF (x=-4)
table38.dat 138 120 Lick indices computed for the (CN-strong)
abundance pattern of NGC 6528, adopting the
solar-scaled Padova isochrones by Girardi et al.
(2000A&AS..141..371G 2000A&AS..141..371G) and a Salpeter IMF.
table39.dat 138 120 Model that best matches indices in the stacked
SDSS spectrum for <Mr> = -20.78
table40.dat 138 120 Model that best matches indices in the stacked
SDSS spectrum for <Mr> = -21.25
table41.dat 138 120 Model that best matches indices in the stacked
SDSS spectrum for <Mr> = -21.73
table42.dat 138 120 Model that best matches indices in the stacked
SDSS spectrum for <Mr> = -22.19
table43.dat 115 16 Corrections to σ=0km/s, for a 1.5 Gyr-old
stellar population with solar metallicity
table44.dat 115 16 Corrections to σ=0km/s, for a 3.5 Gyr-old
stellar population with solar metallicity
table45.dat 115 16 Corrections to σ=0km/s, for a 7.9 Gyr-old
stellar population with solar metallicity
table46.dat 115 16 Corrections to σ=0km/s, for a 14.1 Gyr-old
stellar population with solar metallicity
models.dat 164 6 Recapitulation table of the 6 models used to
compute Lick indices
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See also:
J/AJ/127/1513 : Lick indices on M67 members (Schiavon+, 2004)
J/ApJ/601/485 : Synthetic Lick indices of alpha-enhanced stars
(Franchini+, 2004)
J/ApJ/613/312 : Synthetic Lick indices of alpha-enhanced stars. II.
(Franchini+, 2004)
Byte-by-byte Description of file: table30.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Stellar identification
12- 16 I5 K Teff Effective temperature
18- 22 F5.2 [cm/s2] log(g) Log of the surface gravity
24- 28 F5.2 [Sun] [Fe/H] Metallicity
30- 35 F6.2 mag Mbol Bolometric magnitude
37- 41 F5.2 mag VMAG Absolute V band magnitude
43- 47 F5.2 mag (B-V)0 Intrinsic (B-V) color index
49- 54 F6.3 0.1nm HdF Lick HδF index in Angstroms
56- 61 F6.3 0.1nm HdA Lick HδA index in Angstroms
63- 68 F6.3 mag CN1 Lick CN1 index
70- 75 F6.3 mag CN2 Lick CN2 index
77- 82 F6.3 0.1nm Ca4227 Lick Ca4227 index in Angstroms
84- 89 F6.3 0.1nm G4300 Lick G4300 index in Angstroms
91- 97 F7.3 0.1nm HgF Lick HγF index in Angstroms
99-104 F6.3 0.1nm HgA Lick HγA index in Angstroms
106-111 F6.3 0.1nm Fe4383 Lick Fe4383 index in Angstroms
113-118 F6.3 0.1nm C2-4668 ? Lick C24668 index in Angstroms
120-125 F6.3 0.1nm Hb Lick Hβ index in Angstroms
127-132 F6.3 0.1nm Fe5015 Lick Fe5015 index in Angstroms
134-139 F6.3 0.1nm Mgb Lick Mg b index in Angstroms
141-145 F5.3 mag Mg2 Lick Mg2 index
147-152 F6.3 0.1nm Fe5270 Lick Fe5270 index in Angstroms
154-159 F6.3 0.1nm Fe5335 Lick Fe5335 index in Angstroms
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Byte-by-byte Description of file: table3[34].dat
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Bytes Format Units Label Explanations
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1- 5 F5.2 Gyr Age [0.1,17.7] Model age
7- 11 F5.2 [Sun] [Fe/H] [-1.3,0.4] Model metallicity
13- 17 F5.3 mag VMAG1 Absolute V band magnitude (1)
19- 23 F5.3 mag (B-V)1 The (B-V) color index (1)
25- 30 F6.3 mag (U-B)1 The (U-B) color index (1)
32- 36 F5.3 mag VMAG2 Absolute V band magnitude (2)
38- 42 F5.3 mag (B-V)2 The (B-V) color index (2)
44- 49 F6.3 mag (U-B)2 The (U-B) color index (2)
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Note (1): Obtained using the calibrations presented in Paper I.,
(Schiavon et al., 2002ApJ...580..850S 2002ApJ...580..850S)
Note (2): Obtained integrating the colors provided by Girardi et al.
(2000A&AS..141..371G 2000A&AS..141..371G).
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Byte-by-byte Description of file: table3[1256789].dat table4[012].dat
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Bytes Format Units Label Explanations
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1- 5 F5.2 Gyr Age [0.1,17.7] Model age
7- 10 F4.1 [Sun] [Fe/H] [-1.3,0.3] Model metallicity
12- 16 F5.2 --- x [-4,1.35] IMF power law index (1)
18- 24 F7.4 0.1nm HdF Lick HδF index in Angstroms
26- 32 F7.4 0.1nm HdA Lick HδA index in Angstroms
34- 40 F7.4 mag CN1 Lick CN1 index
42- 48 F7.4 mag CN2 Lick CN2 index
50- 56 F7.4 0.1nm Ca4227 Lick Ca4227 index in Angstroms
58- 64 F7.4 0.1nm G4300 Lick G4300 index in Angstroms
66- 72 F7.4 0.1nm HgF Lick HγF index in Angstroms
74- 80 F7.4 0.1nm HgA Lick HγA index in Angstroms
82- 88 F7.4 0.1nm Fe4383 Lick Fe4383 index in Angstroms
90- 96 F7.4 0.1nm C2-4668 Lick C24668 index in Angstroms
98-103 F6.4 0.1nm Hb Lick Hβ index in Angstroms
105-110 F6.4 0.1nm Fe5015 Lick Fe5015 index in Angstroms
112-117 F6.4 0.1nm Mgb Lick Mg b index in Angstroms
119-124 F6.4 mag Mg2 Lick Mg2 index
126-131 F6.4 0.1nm Fe5270 Lick Fe5270 index in Angstroms
133-138 F6.4 0.1nm Fe5335 Lick Fe5335 index in Angstroms
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Note (1): the power-law of the initial mass function (IMF) relates the
number of stars φ with the mass M with
dφ/dM ∝ M(1-x)
(for a Salpeter law, x=1.35; x=-4.0 for a dwarf-poor IMF).
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Byte-by-byte Description of file: table4[3456].dat
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Bytes Format Units Label Explanations
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1- 3 I3 km/s sig [25,400] Velocity dispersion σ
5- 10 F6.4 0.1nm HdF Lick HδF index in Angstroms (1)
12- 17 F6.4 0.1nm HdA Lick HδA index in Angstroms (1)
19- 24 F6.4 mag CN1 Lick CN1 index (1)
26- 31 F6.4 mag CN2 Lick CN2 index (1)
33- 38 F6.4 0.1nm Ca4227 Lick Ca4227 index in Angstroms (1)
40- 45 F6.4 0.1nm G4300 Lick G4300 index in Angstroms (1)
47- 52 F6.4 0.1nm HgF Lick HγF index in Angstroms (1)
54- 59 F6.4 0.1nm HgA Lick HγA index in Angstroms (1)
61- 66 F6.4 0.1nm Fe4383 Lick Fe4383 index in Angstroms (1)
68- 73 F6.4 0.1nm C2-4668 Lick C24668 index in Angstroms (1)
75- 80 F6.4 0.1nm Hb Lick Hβ index in Angstroms (1)
82- 87 F6.4 0.1nm Fe5015 Lick Fe5015 index in Angstroms (1)
89- 94 F6.4 0.1nm Mgb Lick Mg b index in Angstroms (1)
96-101 F6.4 mag Mg2 Lick Mg2 index (1)
103-108 F6.4 0.1nm Fe5270 Lick Fe5270 index in Angstroms (1)
110-115 F6.4 0.1nm Fe5335 Lick Fe5335 index in Angstroms (1)
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Note (1): Corrections are multiplicative for indices defined as equivalent
widths and additive for those defined in magnitudes.
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Byte-by-byte Description of file: models.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- M Model number
4-164 A161 --- Model Explanation of the model
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History:
From electronic version of the journal
References:
Schiavon et al., Paper I. 2002ApJ...580..850S 2002ApJ...580..850S
Schiavon et al., Paper II. 2002ApJ...580..873S 2002ApJ...580..873S
Schiavon et al., Paper III. 2003astro.ph.12164S 2003astro.ph.12164S
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 20-Apr-2009