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Photometric Constraints on Chemical Evolution Models of Irregular Galaxies

Leticia Carigi·Gustavo Bruzual
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Abstract

Photometric properties of stellar populations that evolve according to chemical evolution models developed by Carigi, Colin, & Peimbert (1999) and Carigi & Peimbert (2001) are explored. Models explain the oxygen abundance and gas mass fraction of irregular galaxies NGC 1560, I Zw 18, NGC 2366, and a typical irregular galaxy. The photometric predictions help to narrow down the range of possible chemical evolution models. Observed colors of I Zw 18 imply an age of 10^8 - 10^9 yr for its dominant population, while 10^9 - 10^{10} yr is an older age preferred by the rest of the galaxy sample. Observed colors are in general, within errors, close to predicted. There is a tendency for the observed (B-V) color to imply higher metallicities at a fixed age than (U-B) (equivalently, (U-B) implies younger ages than (B-V)).

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Leticia Carigi, Gustavo Bruzual. 2000-09-26. Photometric Constraints on Chemical Evolution Models of Irregular Galaxies. https://arxiv.org/abs/astro-ph/0009419

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