to IAU
Symposium 241

Abstract details

Chemical clocks for early-type galaxies in clusters
C. Carretero, A. Vazdekis and J.E. Beckman

We present the values of CN, C and Mg overabundances with respect to Fe, for a large sample of elliptical galaxies in clusters with varying X-ray luminosity. Abundances were derived by confronting observed absorption line indices with stellar population model spectra. We obtained significant differences between the [CN/Fe], [C/Fe] and [Mg/Fe] abundance ratios as a function of the cluster mass. This is interpreted as implying varying formation timescales for CN, C, Mg and Fe, combined with different star formation histories in elliptical galaxies depending on their environment. Our principal conclusions are: 1) CN and C are sensitive to the characteristic star formation timescales of elliptical galaxies, 2) elliptical galaxies in denser environments have shorter star formation histories than those galaxies in lower density environments, and 3) our results strongly suggest an upper limit for the stellar population formation timescale of ~1 Gy, in all cases.

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