Clump mass function at an early stage of molecular cloud evolution: II. Galactic cloud complexes

TL;DR

This study tests a statistical model of the clump mass function against observational data from Galactic molecular cloud complexes, revealing a two-part power-law distribution consistent with gravitationally bound clumps and the stellar initial mass function.

Contribution

It provides observational validation for a statistical approach to the clump mass function, highlighting its two-part power-law structure across different mass regimes.

Findings

ClMF is well described by two power-law functions separated by a characteristic mass.

Intermediate-mass ClMF slope is shallow and nearly constant (-0.25 to -0.55).

High-mass ClMF slope ranges from -0.9 to -1.6, aligning with the stellar IMF slope.

Abstract

The statistical approach for derivation of the clump mass function (ClMF) developed by Donkov, Veltchev & Klessen is put to observational test through comparison with mass distributions of clumps from molecular emission and dust continuum maps of Galactic cloud complexes, obtained by various authors. The results indicate gravitational boundedness of the dominant clump population, with or without taking into account the contribution of their thermal and magnetic energy. The ClMF can be presented by combination of two power-law functions separated by a characteristic mass from about ten to hundreds solar masses. The slope of the intermediate-mass ClMF is shallow and nearly constant (-0.25 \gtrsim \Gamma_{IM} \gtrsim -0.55) while the high-mass part is fitted by models that imply gravitationally unstable clumps and exhibit slopes in a broader range (-0.9 \gtrsim \Gamma_{IM} \gtrsim -1.6), centered at the value of the stellar initial mass function (\Gamma_{HM} \gtreqless -1.3).