to IAU
Symposium 241

Abstract details

Stellar populations in the central regions of two nearby elliptical galaxies through two methods
Andre de Castro Milone (INPE, Brazil), Miriani Pastoriza and Mauro Rickes (UFRGS, Brazil)

The stellar content of two E galaxies at z$\simeq$0 has been investigated in order to analyze the spatial distribution of their parameters such as age, metallicity and Mg/Fe ratio. One of them is a Liner, has a rotating stellar disc and it is the third brightest galaxy of a group. The other one is a field triaxial spheroid. We have compared the spectral data collected along both photometric axes (Lick/IDS indices) with the theoretical predictions of a grid of single-aged stellar populations. A stellar population synthesis has also been applied using a base with seven components. The gradients of some Lick indices have been analyzed as well. In both Es, the Mg/Fe ratio is not homogeneous in their central regions up to nearly 0.6-0.9 r$_{eff}$ (0 $\leq$ [Mg/Fe] $\leq$ +0.6 dex). C, Ca and Na have similar behaviors. The global metallicity increases outwards or it is nearly constant. However, the iron abundance seems to increase outwards in both galaxies while the ages are greater at the nuclei. Therefore, the star formation history has had different timescales inside the central regions causing a non-uniform contribution of type Ia SN relative to type II.

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