Core mass function in view of fractal and turbulent filaments and fibers

TL;DR

This paper models the core mass function (CMF) in star-forming filaments using a fractal and turbulent framework, showing how filament fragmentation can produce a CMF similar to observed initial mass functions.

Contribution

It introduces a fractal and turbulent tree model to explain the CMF, linking filament properties to star formation and universal CMF characteristics.

Findings

The model produces a Kroupa-IMF-like CMF with three power-law segments.

Turnover masses are about four times those of the Kroupa IMF, indicating star formation efficiency.

Adjusting the turbulence parameter $eta$ affects the high-mass slope of the CMF.

Abstract

We propose that the core mass function (CMF) can be driven by filament fragmentation. To model a star-forming system of filaments and fibers, we develop a fractal and turbulent tree with a fractal dimension of 2 and a Larson's law exponent ($\beta$) of 0.5. The fragmentation driven by convergent flows along the splines of the fractal tree yields a Kroupa-IMF-like CMF that can be divided into three power-law segments with exponents $\alpha$ = $-0.5$, $-1.5$, and $-2$, respectively. The turnover masses of the derived CMF are approximately four times those of the Kroupa IMF, corresponding to a star formation efficiency of 0.25. Adopting $\beta=1/3$, which leads to fractional Brownian motion along the filament, may explain a steeper CMF at the high-mass end, with $\alpha=-3.33$ close to that of the Salpeter IMF. We suggest that the fibers of the tree are basic building blocks of star formation, with similar properties across different clouds, establishing a common density threshold for star formation and leading to a universal CMF.