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The Early Chemical Evolution of Dwarf Irregular Galaxies

Published online by Cambridge University Press:  30 March 2016

Gerhard Hensler
Affiliation:
Institute of Astronomy, University Observatory, Türkernschanzstr. 11, A-1080 Vienna, Austria Institute of Theoretical Physics and Astrophysics, University of Kiel, Olshausenstr. 40, D-24098 Kiel, Germany
Simone Recchi
Affiliation:
Institute of Astronomy, University Observatory, Türkernschanzstr. 11, A-1080 Vienna, Austria Institute of Theoretical Physics and Astrophysics, University of Kiel, Olshausenstr. 40, D-24098 Kiel, Germany
Joachim Köppen
Affiliation:
Institute of Theoretical Physics and Astrophysics, University of Kiel, Olshausenstr. 40, D-24098 Kiel, Germany UMR 7550, Observatoire Astronomique de Strasbourg, 11 rue de l’Universit, F-67000 Strasbourg, France
Andreas Rieschick
Affiliation:
Institute of Theoretical Physics and Astrophysics, University of Kiel, Olshausenstr. 40, D-24098 Kiel, Germany

Abstract

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Investigations have been performed to understand the age of dwarf irregular galaxies from the point of view of their presently low chemical abundances and the enhanced star-formation rate. While for a few objects, like e.g. I Zw 18, their assumed relative youth can be verified by models taking a double-starburst behavior into account, those dlrrs with old underlying stellar populations have passed the regime of observed N/O-0 values within almost 2 Gyrs after their formation even with gas loss by means of supernova-driven galactic winds. Therefore alternative processes like gas infall must be invoked.

Type
I. Joint Discussions
Copyright
Copyright © Astronomical Society of Pacific 2005

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