Metallicity and abundance ratios in elliptical galaxies
Open Access
- 1 February 1996
- journal article
- Published by Oxford University Press (OUP) in Monthly Notices of the Royal Astronomical Society
- Vol. 278 (3) , 841-844
- https://doi.org/10.1093/mnras/278.3.841
Abstract
Using the theoretical results of Barbuy, the variation of the Mg2 index as a function of the stellar parameters ( Teff, log g, [Fe/H] ), including the Mg/Fe ratio, is obtained. This allows a new calibration of the metallicity indicators Mg2 and (Fe) through synthetic indices computed for stellar populations having a metallicity spread and ages of the order of 14–16 Gyr. The models indicate that the integrated Mg2 index depends on the chemical history, since it varies not only with the metallicity but also with the average Mg/Fe ratio. The study of a sample of elliptical galaxies shows that on average, #### = 0.40, comparable to the values observed in metal-poor galactic halo stars. This confirms the early suspicions that elliptical galaxies (Es) had a very high star formation rate in the past, and that the enrichment was caused by massive stars.Keywords
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