Gravity or turbulence? -III. Evidence of pure thermal Jeans fragmentation at ~0.1 pc scale

TL;DR

This study investigates whether turbulence or thermal support primarily influences fragmentation in massive dense cores, finding evidence that thermal Jeans fragmentation is the dominant process at a 0.1 pc scale.

Contribution

The paper provides observational evidence that thermal Jeans fragmentation, rather than turbulence, primarily governs the fragmentation of massive dense cores.

Findings

No correlation between fragmentation level and velocity dispersion.

Fragmentation correlates best with pure thermal Jeans predictions.

Core formation efficiency around 13% consistent with previous studies.

Abstract

We combine previously published interferometric and single-dish data of relatively nearby massive dense cores that are actively forming stars to test whether their `fragmentation level' is controlled by turbulent or thermal support. We find no clear correlation between the fragmentation level and velocity dispersion, nor between the observed number of fragments and the number of fragments expected when the gravitationally unstable mass is calculated including various prescriptions for `turbulent support'. On the other hand, the best correlation is found for the case of pure thermal Jeans fragmentation, for which we infer a core formation efficiency around 13 per cent, consistent with previous works. We conclude that the dominant factor determining the fragmentation level of star-forming massive dense cores at 0.1 pc scale seems to be thermal Jeans fragmentation.