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J/ApJ/621/673    Line indices for 124 early-type galaxies        (Thomas+, 2005)

The epochs of early-type galaxy formation as a function of environment. Thomas D., Maraston C., Bender R., De Oliveira C.M. <Astrophys. J., 621, 673-694 (2005)> =2005ApJ...621..673T
ADC_Keywords: Abundances ; Velocity dispersion ; Galaxies, spectra ; Spectroscopy Keywords: galaxies: abundances - galaxies: elliptical and lenticular, cD - galaxies: evolution - galaxies: formation - galaxies: stellar content Abstract: The aim of this paper is to set constraints on the epochs of early-type galaxy formation through the "archaeology" of the stellar populations in local galaxies. Using our models of absorption-line indices that account for variable abundance ratios, we derive ages, total metallicities, and element ratios of 124 early-type galaxies in high- and low-density environments. The data are analyzed by comparison with mock galaxy samples created through Monte Carlo simulations taking the typical average observational errors into account, in order to eliminate artifacts caused by correlated errors. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 87 124 Sample parameters and line indices table3.dat 45 124 Results for population parameters
See also: J/A+A/395/431 : Line-strength indices for 148 early-type galaxies (Beuing+, 2002) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 11 A11 --- Name Source name 13- 17 F5.1 km/s Sigma Velocity dispersion 19- 22 F4.1 km/s e_Sigma The 1σ error in Sigma 24- 27 F4.2 0.1nm Hb The Hβ line index 29- 32 F4.2 0.1nm e_Hb The 1σ error in Hb 34- 37 F4.2 0.1nm Mgb The Mg b line index 39- 42 F4.2 0.1nm e_Mgb The 1σ error in Mgb 44- 47 F4.2 0.1nm <Fe> The <Fe> line index 49- 52 F4.2 0.1nm e_<Fe> The 1σ error in <Fe> 54- 55 A2 --- Morph Galaxy morphology type 57- 68 A12 --- Den Environmental density (low or high) 70- 77 A8 --- Ref Literature source (1) 79- 87 A9 --- Class Classification by symbol type in Fig. 4 (2)
Note (1): Sources for the data, defined as follows: Gonzalez = Gonzales (1993, Ph.D. thesis, Univ. California, Santa Cruz), Beuing = Beuing et al. (2002, Cat. J/A+A/395/431), Mehlert = Mehlert et al. (2003, Cat. J/A+A/407/423), Oliveira = Mendes de Oliveira et al. (in preparation). Note (2): The symbol types used in Fig. 4 are defined as follows: circles = linear relationships of age, metallicity, and α/Fe ratio with velocity dispersion diamonds = realizations in which 70% of the galaxy's stellar populations is assumed to form around a look-back time of 2.5Gyr squares = simulations assuming 1.4Gyr old subcomponents (20% in mass) triangles = simulations assuming 1.2Gyr old subcomponents (10% in mass)
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 11 A11 --- Name Source name 13- 16 F4.1 Gyr Age Stellar population age (1) 18- 20 F3.1 Gyr e_Age 1σ error in Age (2) 22- 26 F5.3 [Sun] [Z/H] Log of the total Z/H abundance (1) 28- 32 F5.3 [Sun] e_[Z/H] The 1σ error in [Z/H] (2) 34- 39 F6.3 [Sun] [a/Fe] Log of the α/Fe abundance (1) 41- 45 F5.3 [Sun] e_[a/Fe] The 1σ error in [a/Fe](2)
Note (1): The stellar population parameters age, total metallicity [Z/H], and [a/Fe] abundance ratio are derived from Hβ, Mg b, and <Fe> (Table 2) using SSP models of Thomas et al. (2003MNRAS.343..279T) and Thomas et al. (2004MNRAS.351L..19T). Note (2): Estimated via Monte Carlo simulations (see text).
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Marianne Brouty [CDS] 31-Aug-2005
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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