Gravitational Infall onto Molecular Filaments

TL;DR

This paper analytically investigates how environmental factors influence the evolution of molecular filaments, showing that accretion impacts their properties and can explain observed structures like infrared-dark cloud fans.

Contribution

It introduces an analytical approach to understanding filament evolution, emphasizing the importance of environmental effects and accretion in shaping observed features.

Findings

Accretion explains the decorrelation between filament width and column density.

Tidal forces at filament ends can produce infrared-dark cloud fans.

Environmental effects are crucial for realistic filament evolution models.

Abstract

Two aspects of filamentary molecular cloud evolution are addressed: (1) Exploring analytically the role of the environment for the evolution of filaments demonstrates that considering them in isolation (i.e. just addressing the fragmentation stability) will result in unphysical conclusions about the filament's properties. Accretion can also explain the observed decorrelation between FWHM and peak column density. (2) Free-fall accretion onto finite filaments can lead to the characteristic "fans" of infrared-dark clouds around star-forming regions. The fans may form due to tidal forces mostly arising at the ends of the filaments, consistent with numerical models and earlier analytical studies.