Evidence for a Turnover in the IMF of Low Mass Stars and Sub-stellar Objects: Analysis from an Ensemble of Young Clusters

TL;DR

This study combines data from seven young star-forming regions to analyze the low-mass initial mass function, providing evidence that the sub-stellar IMF exhibits a turnover, consistent with a log-normal distribution.

Contribution

It demonstrates that the ratios of stars to brown dwarfs are consistent across multiple regions, constrains the shape of the brown dwarf IMF, and provides strong evidence for a turnover in the sub-stellar IMF.

Findings

Ratios of stars to brown dwarfs are consistent across regions.

The brown dwarf IMF is consistent with a log-normal distribution.

Evidence for a turnover in the sub-stellar IMF with a negative slope.

Abstract

We present a combined analysis of the low-mass Initial Mass Function (IMF) for seven star forming regions. We first demonstrate that the ratios of stars to brown dwarfs are consistent with a single underlying IMF. Assuming the underlying IMF is the same for all seven clusters and by combining the ratio of stars to brown dwarfs from each cluster we constrain the shape of the brown dwarf IMF and find it to be consistent with a log--normal IMF. This provides the strongest constraint yet that the sub-stellar IMF turns over (dN/dM M^(-alpha), alpha < 0).