Issue |
A&A
Volume 422, Number 1, July IV 2004
|
|
---|---|---|
Page(s) | 55 - 64 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361:20047071 | |
Published online | 06 July 2004 |
Periodic bursts of star formation in irregular galaxies
Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
Corresponding author: F. I. Pelupessy, pelupes@strw.leidenuniv.nl
Received:
14
January
2004
Accepted:
24
March
2004
We present N-body/SPH simulations of the evolution of an isolated dwarf
galaxy including a detailed model for the ISM, star formation and stellar
feedback. Depending on the strength of the feedback, the modelled dwarf galaxy
shows periodic or quasi-periodic bursts of star formation of moderate
strength. The period of the variation is related to the dynamical timescale,
of the order of 1.5 108 yr. We show that the results of these simulations
are in good agreement with recent detailed observations of dwarf irregulars (dIrr) and
that the peculiar kinematic and morphological properties of these objects,
as revealed by high resolution HI studies, are fully reproduced. We discuss these
results in the context of recent surveys of dwarf galaxies and point out that if
the star formation pattern of our model galaxy is typical of dwarf irregulars this
could explain the scatter of observed properties of dwarf galaxies. Specifically,
we show that the time-sampled distribution of the ratio between the instanteneous
star formation rate (SFR) and the mean SFR is similar to the
distribution in observed samples of dwarf galaxies.
Key words: methods: numerical / methods: N-body simulations / galaxies: dwarf / Galaxy: evolution / galaxies: ISM / galaxies: irregular
© ESO, 2004
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