Dynamical and chemical evolution of gas-rich dwarf galaxies
- Author(s)
- Simone Recchi, Francesca Matteucci, Annibale D'Ercole
- Abstract
We study the effect of a single, instantaneous starburst on the dynamical and chemical evolution of a gas-rich dwarf galaxy, the potential well of which is dominated by a dark matter halo. We follow the dynamical and chemical evolution of the interstellar medium (ISM) by means of an improved two-dimensional hydrodynamical code coupled with detailed chemical yields originating from type II SNe, type Ia SNe and single low- and intermediate-mass stars (IMS). In particular we follow the evolution of the abundances of H, He, C, N, O, Mg, Si and Fe. We find that for a galaxy resembling IZw18, a galactic wind develops as a consequence of the starburst and it carries out of the galaxy mostly the metal-enriched gas. In addition, we find that different metals are lost differentially in the sense that the elements produced by type Ia SNe are lost more efficiently than others. As a consequence of that, we predict larger [a/Fe] ratios for the gas inside the galaxy than for the gas leaving the galaxy. A comparison of our predicted abundances of C, N, O and Si in the case of a burst occurring in a primordial gas shows a very good agreement with the observed abundances in IZw18 as long as the burst has an age of ~31 Myr and IMS produce some primary nitrogen. However, we cannot exclude that a previous burst of star formation had occurred in IZw18, especially if the pre-enrichment produced by the older burst was lower than Z = 0.01 Z?. Finally, at variance with previous studies, we find that most of the metals reside in the cold gas phase already after a few Myr. This result is mainly caused by the assumed low SN II heating efficiency, and justifies the generally adopted homogeneous and instantaneous mixing of gas in chemical evolution models.
- Organisation(s)
- Department of Astrophysics
- External organisation(s)
- Università degli Studi di Trieste, INAF-Osservatorio Astronomico di Bologna
- Journal
- Monthly Notices of the Royal Astronomical Society
- Volume
- 322
- Pages
- 800-820
- No. of pages
- 21
- ISSN
- 0035-8711
- Publication date
- 2001
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103003 Astronomy
- Portal url
- https://ucris.univie.ac.at/portal/en/publications/dynamical-and-chemical-evolution-of-gasrich-dwarf-galaxies(343251de-993f-4dbc-8c7f-b7dd2713e105).html