Fragmentation in Molecular Clouds and its connection to the IMF

TL;DR

This study analyzes star-forming gas cores in molecular clouds using simulations, revealing that bound potential cores resemble the stellar initial mass function and emphasizing the role of environment and accretion in core evolution.

Contribution

It introduces a method to identify pre-stellar cores via potential wells and links core properties to star formation, highlighting environmental influences.

Findings

P-core mass function resembles the stellar IMF.

Bound p-cores are generally subsonic and quasi-spherical.

Poor correlation between initial core mass and final stellar mass.

Abstract

We present an analysis of star-forming gas cores in an SPH simulation of a Giant Molecular Cloud. We identify cores using their deep potential wells. This yields a smoother distribution with clearer boundaries than density. Additionally, this gives an indication of future collapse, as bound potential cores (p-cores) represent the earliest stages of fragmentation in molecular clouds. We find that the mass function of the p-cores resembles the stellar IMF and the observed clump mass function, although p-core masses (~0.7 Msol) are smaller than typical density clumps. The bound p-cores are generally subsonic, have internal substructure, and are only quasi-spherical. We see no evidence of massive bound cores supported by turbulence. We trace the evolution of the p-cores forward in time, and investigate the connection between the original p-core mass and the stellar mass that formed from it. We find that there is a poor correlation, with considerable scatter suggesting accretion onto the core is dependent on more factors than just the initial core mass. During the accretion process the p-cores accrete from beyond the region first bound, highlighting the importance of the core environment to its subsequent evolution.