Published online by Cambridge University Press: 10 November 2010
We discuss the effects of a change of the mass loss rates of massive stars on the outputs of population synthesis models of starbursts. We find that models with high mass loss rates well account for the observed ratios of WNL to O-type stars in starburst galaxies.
Stellar evolutionary tracks and starburst models
The stellar populations as observed after a starburst episode depend on:
The intensity as a function of time of the star formation rate (SFR) during the starburst. The observed properties of the starburst may also depend on the much lower SFR if this prevails between bursts of star formation. However, for very intense bursts, these “underlying” populations can be completely blurred out by the numerous new born stars.
The slope of the initial mass function (IMF) and the lower and upper mass limits of the stars born in the burst.
The time elapsed since the beginning of the burst (which we shall call here the age of the starburst).
Some physical ingredients of the stellar models as, for instance, the mass loss rates by stellar winds and the metallicity.