2008/10/22 by James M. Schombert, J. Schombert, K. D. Rakos +3
Chemistry · Engineering · Physics and Astronomy · #Astrophysics (astro-ph) #Dyeing and Modifying Textile Fibers #FOS: Physical sciences #Spectroscopy and Chemometric Analyses #astro-ph
paper · pdf · doi:10.48550/arxiv.0810.4102
21 pages, 6 figures, accepted in AJ
arxiv created 2008/10/22 · openalex publication_date 2008/10/22 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
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.