Tests of Chemical Enrichment Scenarios in Ellipticals Using Continuum Colors and Spectroscopy

J. Schombert; K. Rakos

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arXiv · 0810.4102

Tests of Chemical Enrichment Scenarios in Ellipticals Using Continuum Colors and Spectroscopy

J. Schombert·K. Rakos

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Abstract

We combine spectroscopic metallicity values with integrated narrowband continuum colors to explore the internal metallicity distribution in early-type galaxies. The different techniques for determining metallicity (indices versus colors) allows for an estimate of the contribution from metal-poor stars in a predominantly metal-rich population which, in turn, places constraints on the shape and width of a galaxy's metallicity distribution function (MDF). The color-spectroscopic data is compared to the closed box, infall and inhomogeneous chemical evolution models. The G-dwarf problem, a deficiency in metal-poor stars as compared to closed box models, is evident in the dataset and indicates this deficiency is common to all early-type galaxies. However, even simple infall models predict galaxy colors which are too blue compared to the observations. A simple analytic model is proposed which matches the elliptical data and recent HST observations of M31 (Worthey et al 2005) and NGC 5128 (Harris & Harris 2000) by reducing the number of metal-poor stars in a systematic fashion. While without physical justification, the shape of these models are similar to predictions of inhomogeneous enrichment scenarios.

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J. Schombert, K. Rakos. 2008-10-22. Tests of Chemical Enrichment Scenarios in Ellipticals Using Continuum Colors and Spectroscopy. https://arxiv.org/abs/0810.4102

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