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J/A+A/463/455   Nearby early-type gal. with ionized gas. III.  (Annibali+, 2007)

Nearby early-type galaxies with ionized gas. III. Analysis of line-strength indices with new stellar population models. Annibali F., Bressan A., Rampazzo R., Zeilinger W.W., Danese L. <Astron. Astrophys. 463, 455 (2007)> =2007A&A...463..455A
ADC_Keywords: Galaxies, nearby ; Abundances ; Models, evolutionary Keywords: galaxies: elliptical and lenticular, cD - galaxies: fundamental parameters - galaxies: formation - galaxies: evolution Abstract: The paper is devoted to the study of the underlying stellar population of a sample of 62 nearby early-type galaxies, predominantly located in low density environments, a large fraction of which showing emission lines. Ages, metallicities and [α/Fe] ratios have been derived through the comparison of Lick indices measured at different galacto-centric distances (7 apertures and 4 gradients) with new Simple Stellar Population (SSP) models which account for the presence of alpha/Fe-enhancement. The SSPs cover a wide range of ages (108-16x109yr), metallicities (0.0004≤Z≤0.05) and [α/Fe] ratios (0-0.8). To derive the stellar population parameters we use an algorithm that provides, together with the most likely solution in the (age, Z, [α/Fe]) space, also the probability density function along the age-metallicity degeneracy. We derive a large spread in age, with SSP-equivalent ages ranging from a few to 15Gyrs. Age does not show any significant trend with central velocity dispersion sigmac but E galaxies appear on average older than lenticulars. Description: Ages, metallicities and [α/Fe] ratios derived for all the apertures and gradients of the total sample of 62 galaxies are presented. Each table presents the results obtained with one particular choice of the line strength index triplets: (Hβ, Mgb, and <Fe>), (Hγ_F, Mgb, and <Fe>) and (Hδ_F, Mgb, and <Fe>). From 0 to 6, the apertures correspond to regions of increasing radii: 1.5" (0), 2.5" (1), 10" (2), re/10 (3), re/8 (4), re/4 (5) and re/2 (6). From 0 to 3 the gradients correspond to adjacent annulii of increasing radii: 0≤r≤re/16 (0), re/16≤r≤re/8 (1), re/8≤r≤re/4 (2) and re/4≤r≤re/2 (3). File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file galaxies.dat 50 62 Galaxy positions (From Simbad) table5.dat 61 415 Apertures: ages, metallicities and [α/Fe] ratios from (Hβ, Mgb, and <Fe>) table6.dat 61 415 Apertures: ages, metallicities and [α/Fe] ratios from (HγF, Mgb, and <Fe>) table7.dat 61 415 Apertures: ages, metallicities and [α/Fe] ratios from (HδF, Mgb, and <Fe>) table9.dat 61 227 Gradients: ages, metallicities and [α/Fe] ratios from (Hβ, Mgb, and <Fe>) table10.dat 61 227 Gradients: ages, metallicities and [α/Fe] ratios from (HγF, Mgb, and <Fe>) table11.dat 61 227 Gradients: ages, metallicities and [α/Fe] ratios from (HδF, Mgb, and <Fe>) table12.dat 61 224 Gradients: final ages, metallicities and [α/Fe] ratios
See also: J/A+A/433/497 : Nearby early-type gal. with ionized gas. I. (Rampazzo+, 2005) J/A+A/445/79 : Nearby early-type gal. with ionized gas. II. (Annibali+, 2006) J/A+A/519/A40 : Nearby early-type gal. with ionized gas. IV (Annibali+, 2010) Byte-by-byte Description of file: galaxies.dat
Bytes Format Units Label Explanations
1- 8 A8 --- Galaxy Simbad name 11- 12 I2 h RAh Simbad Hour of Right Ascension (J2000.0) 14- 15 I2 min RAm Simbad Minute of Right Ascension (J2000.0) 17- 20 F4.1 s RAs Simbad Second of Right Ascension (J2000.0) 22 A1 --- DE- Simbad Sign of the Declination (J2000.0) 23- 24 I2 deg DEd Simbad Degree of Declination (J2000.0) 26- 27 I2 arcmin DEm Simbad Arcminute of Declination (J2000.0) 29- 30 I2 arcsec DEs Simbad Arcsecond of Declination (J2000.0) 34- 38 F5.2 mag Bmag Simbad B band magnitude 40- 44 F5.2 mag Vmag ? Simbad V band magnitude 46- 50 A5 --- MType Simbad morphological type
Byte-by-byte Description of file: table[567].dat
Bytes Format Units Label Explanations
1- 8 A8 --- Galaxy Galaxy designation 11 I1 --- Aperture [0/6] Aperture number (1) 16- 19 F4.1 Gyr Age Age 22- 25 F4.1 Gyr e_Age Error on age 32- 36 F5.3 --- Z Metallicity mass fraction 39- 43 F5.3 --- e_Z Error on metallicity 50- 54 F5.3 --- a/Fe α/Fe ratio 57- 61 F5.3 --- e_a/Fe Error on α/Fe ratio
Note (1): Aperture numbers as follows: 0 = 1.5" 1 = 2.5" 2 = 10" 3 = re/10 4 = re/8 5 = re/4 6 = re/2
Byte-by-byte Description of file: table9.dat table1?.dat
Bytes Format Units Label Explanations
1- 8 A8 --- Galaxy Galaxy designation 11 I1 --- Gradient [0/3] Gradient number (1) 16- 19 F4.1 Gyr Age Age 22- 25 F4.1 Gyr e_Age Error on age 32- 36 F5.3 --- Z Metallicity mass fraction 39- 43 F5.3 --- e_Z Error on metallicity 50- 54 F5.3 --- a/Fe α/Fe ratio 57- 61 F5.3 --- e_a/Fe Error on α/Fe ratio
Note (1): Gradient numbers as follows: 0 = 0 ≤ r ≤ re/16 1 = re/16 ≤ r ≤ re/8 2 = re/8 ≤ r ≤ re/4 3 = re/4 ≤ r ≤ re/2
Acknowledgements: Francesca Annibali, annibali(at)stsci.edu
(End) Patricia Vannier [CDS] 28-Sep-2006
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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