| Issue |
A&A
Volume 398, Number 3, February II 2003
|
|
|---|---|---|
| Page(s) | 949 - 957 | |
| Section | Extragalactic astronomy | |
| DOI | https://doi.org/10.1051/0004-6361:20021718 | |
| Published online | 28 January 2003 | |
New 
color distributions in E-type galaxies*
II. Central and mean metallicities
1
Observatoire de la Côte d'Azur, BP 4229, 06304 Nice Cedex 4, France e-mail: pacheco@obs-nice.fr
2
Instituto de Astronomia, Geofísica e Ciências Atmosféricas Depto. de Astronomia, Universidade de São Paulo, Av. Miguel Stefano, 4200-CEP 04301-904, S. Paulo, SP-Brazil e-mail: thais@iagusp.usp.br
3
Observatoire de Paris, LERMA, 77 Av. Denfert-Rochereau, 75015, Paris, France
Corresponding author: R. Michard, raymond.michard@obspm.fr
Received:
17
September
2001
Accepted:
8
November
2002
Central and mean metallicities are calculated for a sample of 40 early-type
galaxies, whose color gradients were reported in a previous paper
(Idiart et al.2002). The present color-metallicity calibration was derived
from a grid of evolutionary models which fit the color-magnitude sequence
of ellipticals in Coma and Virgo clusters. The mean metallicity gradient
derived from our data is ![$(\Delta{\rm [Fe/H]}/\Delta \log r) = -0.26 \pm 0.08$](/articles/aa/abs/2003/06/aa1935/aa1935_tex_eq2.png)
and the mean sample average metallicity is ![${<{\rm [Fe/H]}>} = 0.01 \pm 0.11$](/articles/aa/abs/2003/06/aa1935/aa1935_tex_eq3.png)
(rmsd).
Central and mean metallicities are correlated with the central velocity
dispersion, consistent with the interpretation by metallicity variations
of the color-magnitude sequence and of color gradients. Age effects are
also discussed, in particular concerning the interpretation of
the Hβ line strength in those objects.
Key words: galaxies: ellipticals and lenticular, cD / galaxies: abundances
© ESO, 2003
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