2007A&A...469...89D


C.D.S. - SIMBAD4 rel 1.7 - 2019.11.17CET20:03:08

2007A&A...469...89D - Astronomy and Astrophysics, volume 469, 89-113 (2007/7-1)

The elliptical galaxies NGC1052 and NGC7796. Stellar populations and abundance ratio α/Fe.

DE C. MILONE A., RICKES M.G. and PASTORIZA M.G.

Abstract (from CDS):

Understanding how each early-type galaxy forms and evolves is one of the objectives of extragalactic astrophysics and cosmology. The spatial distribution of the stellar populations inside a spheroidal system and their kinematic properties supply important information about the formation process. The reconstruction of the star formation history is crucial in this context. We have performed a detailed stellar population analysis using long slit spectroscopic observations up to almost one effective radius of two different early-type galaxies of low density regions of the local Universe: NGC1052, an E4 Liner prototype of a loose group that has a stellar rotating disc, and NGC7796, an E1 of the field which shows a kinematically distinct core. Their mean luminosity-weighted stellar age, metallicity, and α/Fe ratio along both photometric axes have been obtained to reconstruct the star formation history in their kinematically distinct subsystems. We have measured Lick indices and computed their radial gradients. They were compared with the predicted ones of simple stellar population models. We have also applied a stellar population synthesis. The star characteristics are associated with their kinematics: they are older and α-enhanced in the bulge of NGC1052 and core of NGC7796, while they show a strong spread of α/Fe and age along the disc of NGC1052 and an outward radial decrease outside the core of NGC7796. The age variation is possibly connected to the α/Fe one. Both galaxies were formed by processes in which the star formation occurred first at the bulge (NGC1052) and nucleus (NGC7796) 12-15Gyr ago on short timescales (0.1-1Gyr), providing an efficient chemical enrichment by SN-II. In the disc of NGC1052, there is some spread of age and formation timescales around its stars. In NGC7796, the star formation timescale had some outward radial increases along both axes.

Abstract Copyright:

Journal keyword(s): galaxies: elliptical and lenticular, cD - galaxies: stellar content - galaxies: individual: NGC1052 - galaxies: individual: NGC7796

Simbad objects: 8

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Number of rows : 8

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NGC 1052 GiP 02 41 04.79851 -08 15 20.7517 11.84 11.41 10.47 10.71   ~ 1104 2
2 NGC 4697 GiG 12 48 35.8992791100 -05 48 02.497675635   10.97   9.83   ~ 784 0
3 HD 148513 PM* 16 28 33.9805980948 +00 39 53.998682880 8.65 6.85 5.39     K3V 148 0
4 * h Her PM* 16 32 36.2919015 +11 29 16.947932 8.16 6.34 4.85 3.65 2.79 K4.5III 141 0
5 * kap Oph LP? 16 57 40.0978499 +09 22 30.112596 5.52 4.36 3.20 2.36 1.82 K2III 281 0
6 * psi01 Aqr PM* 23 15 53.4952540919 -09 05 15.841221338 6.37 5.36 4.25 3.46 2.90 K1-IIIFe-0.5 214 1
7 HD 221148 PM* 23 29 32.0811959294 -04 31 57.881823844   7.34 6.25     K3-IIIbFe2 128 0
8 NGC 7796 G 23 58 59.810 -55 27 30.12   12.36 11.30 10.82   ~ 104 0

    Equat.    Gal    SGal    Ecl

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2019.11.17-20:03:08

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