Issue |
A&A
Volume 373, Number 1, July I 2001
|
|
---|---|---|
Page(s) | L9 - L12 | |
Section | Letters | |
DOI | https://doi.org/10.1051/0004-6361:20010704 | |
Published online | 15 July 2001 |
On star formation rates in dwarf galaxies
Universitäts-Sternwarte, Geismarlandstr. 11, 37083 Göttingen, Germany
Corresponding author: P. Weilbacher, weilbach@uni-sw.gwdg.de
Received:
7
May
2001
Accepted:
16
May
2001
We present evolutionary synthesis models of starbursts on
top of old stellar populations to investigate in detailed time
evolution the relation between Hα luminosity and star formation
rate (SFR). The models show that several effects have an impact on
the ratio between and SFR. Metallicity different from solar
abundance, a time delay between star formation and maximum
Hα-luminosity, and a varying stellar initial mass function give rise
to strong variations in the ratio of Hα luminosity to SFR and can
cause large errors in the determination of the SFR when employing
well-known calibrations. When studying star-bursting dwarf
galaxies, and sub-galactic fragments at high redshift, which show
SFR fluctuating on short timescales, these effects can add up to
errors of two orders of magnitude compared with the calibrations. To
accurately determine the true current SFR additional data in
combination with models for the spectral energy distribution are
needed.
Key words: galaxies: starbursts / galaxies: dwarf / galaxies: evolution / galaxies: fundamental parameters
© ESO, 2001
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