Volume 426, Number 1, October IV 2004
|Page(s)||37 - 51|
|Published online||05 October 2004|
Continuous star formation in IZw18
Institut für theoretische Physik und Astrophysik, Kiel University, Olshausenstrasse 40, 24118 Kiel, Germany e-mail: firstname.lastname@example.org
2 Max-Planck Institut für Astrophysik, Karl-Schwarzschild-Strasse 1, 85741 Garching bei München, Germany
3 Dipartimento di Astronomia, Università di Trieste, Via GB Tiepolo, 11, 34131 Trieste, Italy e-mail: email@example.com
4 INAF - Osservatorio Astronomico di Bologna, Via Ranzani 1, 40127 Bologna, Italy e-mail: [annibale;tosi]@bo.astro.it
Accepted: 25 May 2004
We study the dynamical and chemical evolution of a galaxy similar to IZw18 under the assumption of a continuous star formation during bursts. We adopt a 2-D hydrocode coupled with detailed chemical yields originating from SNeII, SNeIa and from single intermediate-mass stars. Different nucleosynthetic yields and different IMF slopes are tested. In most of the explored cases, a galactic wind develops, mostly carrying out of the galaxy the metal-enriched gas produced by the burst itself. The chemical species with the largest escape probabilities are Fe and N. Consequently, we predict that the [ α/Fe] and [ α/N] ratios outside the galaxy are lower than inside. In order to reproduce the chemical composition of IZw18, the best choice seems to be the adoption of the yields of Meynet & Maeder ([CITE]) which take into account stellar rotation, although these authors do not follow the whole evolution of all the stars. Models with a flat IMF () seem to be able to better reproduce the chemical properties of IZw18, but they inject in the gas a much larger amount of energy and the resulting galactic wind is very strong, at variance with observations. We also predict the evolution of the abundances in the H i medium and compare them with recent FUSE observations.
Key words: hydrodynamics / ISM: abundances / ISM: jets and outflows / galaxies: evolution / galaxies: individual: IZw18 / galaxies: spiral
© ESO, 2004
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.