Does turbulence determine the initial mass function?

TL;DR

This study investigates whether the density distribution caused by turbulence influences the initial mass function (IMF) of stars, finding that different turbulence modes do not significantly alter the IMF despite affecting star formation rates.

Contribution

The paper provides the first direct comparison of IMFs resulting from purely solenoidal versus compressive turbulence modes in star-forming regions, challenging the hypothesis that turbulence density PDFs determine the IMF.

Findings

IMFs are statistically indistinguishable between turbulence modes

Star formation rate varies with turbulence mode

Density PDF influences star formation rate but not the IMF

Abstract

We test the hypothesis that the initial mass function (IMF) is determined by the density probability distribution function (PDF) produced by supersonic turbulence. We compare 14 simulations of star cluster formation in 50 solar mass molecular cloud cores where the initial turbulence contains either purely solenoidal or purely compressive modes, in each case resolving fragmentation to the opacity limit to determine the resultant IMF. We find statistically indistinguishable IMFs between the two sets of calculations, despite a factor of two difference in the star formation rate and in the standard deviation of $\log(\rho)$. This suggests that the density PDF, while determining the star formation rate, is not the primary driver of the IMF.