Applications of the IGIMF-theory to the astrophysics of galaxies

TL;DR

This paper reviews how the integrated galactic initial mass function (IGIMF), which accounts for star formation in groups rather than uniformly, impacts our understanding of galaxy properties and star formation.

Contribution

It summarizes existing applications of the IGIMF theory to galactic astrophysics, highlighting its importance over the traditional assumption of a universal IMF.

Findings

IGIMF is steeper than the canonical IMF

IGIMF steepens with decreasing star formation rate

Implications for star formation properties of galaxies

Abstract

The functional form of the galaxy-wide stellar initial mass function is of fundamental importance for understanding galaxies. So far this stellar initial mass function has been assumed to be identical to the IMF observed directly in star clusters. But because stars form predominantly in embedded groups rather than uniformly distributed over the whole galaxy, the galaxy-wide IMF needs to be calculated by adding all IMFs of all embedded groups. This integrated galactic stellar initial mass function (IGIMF) is steeper than the canonical IMF and steepens with decreasing SFR, leading to fundamental new insights and understanding of star forming properties of galaxies. This contribution reviews the existing applications of the IGIMF theory to galactic astrophysics, while the parallel contribution by Weidner, Pflamm-Altenburg & Kroupa (this volume) introduces the IGIMF theory.