The Galactic IMF: origin in the combined mass distribution functions of dust grains and gas clouds

TL;DR

This paper proposes a theoretical model linking dust grain size and gas cloud properties to explain the stellar initial mass function, integrating dust and gas distribution effects for a better match with observations.

Contribution

It introduces a novel model combining dust grain size effects with gas cloud mass functions to quantitatively reproduce the stellar IMF.

Findings

Dust grain size influences cloud cooling and molecule formation.

Folding dust and gas effects yields a better IMF match than gas alone.

Model aligns with observed stellar mass distributions.

Abstract

We present here a theoretical model to account for the stellar IMF as a result of the composite behaviour of the gas and dust distribution functions. Each of these has previously been modelled and the models tested against observations. The model presented here implies a relation between the characteristic size of the dust grains and the characteristic final mass of the stars formed within the clouds containing the grains, folded with the relation between the mass of a gas cloud and the characteristic mass of the stars formed within it. The physical effects of dust grain size are due to equilibrium relations between the efficiency of grains in cooling the clouds, which is a falling function of grain size, and the efficiency of grains in catalyzing the production of molecular hydrogen, which is a rising function of grain size. We show that folding in the effects of grain distribution can yield a reasonable quantitative account of the IMF, while gas cloud mass function alone cannot do so.