Structural and Dynamical Analysis of 0.1pc Cores and Filaments in the 30~Doradus-10 Giant Molecular Cloud

TL;DR

This study uses high-resolution ALMA data to analyze the structure and dynamics of cores and filaments in the 30Doradus-10 molecular cloud, revealing complex morphology, energy injection, and insights into star formation processes.

Contribution

It provides a detailed multi-method analysis of cloud substructures, highlighting the role of filaments and cores in star formation within a giant molecular cloud.

Findings

Filaments are approximately 0.1pc wide.

Velocity gradients do not strongly support mass accretion along filaments.

Core mass distribution follows a power-law similar to the stellar initial mass function.

Abstract

High-resolution ($<$0.1pc) ALMA observations of the 30Dor-10 molecular cloud 15pc north of R136 are presented. The $^{12}$CO 2-1 emission morphology contains clumps near the locations of known mid-infrared massive protostars, as well as a series of parsec-long filaments oriented almost directly towards R136. There is elevated kinetic energy (linewidths at a given size scale) in 30Dor-10 compared to other LMC and Galactic star formation regions, consistent with large scale energy injection to the region. Analysis of the cloud substructures is performed by segmenting emission into disjoint approximately round "cores" using clumpfind, by considering the hierarchical structures defined by isointensity contours using dendrograms, and by segmenting into disjoint long thin "filaments" using Filfinder. Identified filaments have widths $\sim$0.1pc. The inferred balance between gravity and kinematic motions depends on the segmentation method: Entire objects identified with clumpfind are consistent with free-fall collapse or virial equilibrium with moderate external pressure, whereas many dendrogram-identified parts of hierarchical structures have higher mass surface densities $\Sigma_{LTE}$ than if gravitational and kinetic energies were in balance. Filaments have line masses that vary widely compared to the critical line mass calculated assuming thermal and nonthermal support. Velocity gradients in the region do not show any strong evidence for accretion of mass along filaments. The upper end of the "core" mass distribution is consistent with a power-law with the same slope as the stellar initial mass function.