Filamentary Fragmentation and Accretion in High-Mass Star-Forming Molecular Clouds

TL;DR

This study uses interferometric observations to analyze filamentary structures in high-mass star-forming clouds, revealing their role in core formation, accretion flows, and star formation activity, highlighting complex dynamics beyond thermal or turbulence support.

Contribution

It provides new observational evidence linking filamentary fragmentation and accretion processes to high-mass star formation, emphasizing the importance of gas flows and non-thermal motions.

Findings

Identified 50 dense cores, most associated with high-mass star formation.

Found accretion rates along filaments of approximately 10^{-4} M_sun/yr.

Observed correlation between non-thermal linewidths and star formation activities.

Abstract

Filamentary structures are ubiquitous in high-mass star-forming molecular clouds. Their relation with high-mass star formation is still to be understood. Here we report interferometric observations toward 8 filamentary high-mass star-forming clouds. A total of 50 dense cores are identified in these clouds, most of which present signatures of high-mass star formation. Five of them are not associated with any star formation indicators, hence are prestellar core candidates. Evolutionary phases of these cores and their linewidths, temperatures, NH$_3$ abundances, and virial parameters are found to be correlated. In a sub-sample of 4 morphologically well-defined filaments, we find that their fragmentation can not be solely explained by thermal or turbulence pressure support. We also investigate distributions of gas temperatures and non-thermal motions along the filaments, and find a spatial correlation between non-thermal linewidths and star formation activities. We find evidence of gas flows along these filaments, and derive an accretion rate along filaments of $\sim$10$^{-4}$ M$_\odot$ yr$^{-1}$. These results suggest a strong relationship between massive filaments and high-mass star formation, through i) filamentary fragmentation in very early evolutionary phases to form dense cores, ii) accretion flows along filaments that are important for the growth of dense cores and protostars, and iii) enhancement of non-thermal motion in the filaments by the feedback or accretion during star formation.