The impact of the metallicity and star formation rate on the time-dependent galaxy-wide stellar initial mass function

Understand

The stellar initial mass function (IMF) is commonly assumed to be an invariant probability density distribution function of initial stellar masses being represented by the canonical IMF.

• As a consequence the galaxy-wide IMF (gwIMF), defined as the sum of the IMFs of all star forming regions, should also be invariant.
• Recent observational and theoretical results challenge the hypothesis that the gwIMF is invariant.
• In order to study the possible reasons for this variation we use the IMF determined in resolved star clusters and apply the IGIMF-theory to calculate a grid of gwIMF models for metallicities, -3<[Fe/H]<1, and galaxy-wide star formation rates, $10^{-5}$<SFR<$10^{5}\,\mathrm{M_{\odot}/yr}$.