Filament collapse: a two phase process

Abstract

Using numerical simulations, we investigate the gravitational evolution of filamentary molecular cloud structures and their condensation into dense protostellar cores. One possible process is the so called 'edge effect', the pile-up of matter at the end of the filament due to self-gravity. This effect is predicted by theory but only rarely observed. To get a better understanding of the underlying processes we used a simple analytic approach to describe the collapse and the corresponding collapse time. We identify a model of two distinct phases: The first phase is free fall dominated, due to the self-gravity of the filament. In the second phase, after the turning point, the collapse is balanced by the ram pressure, produced by the inside material of the filament, which leads to a constant collapse velocity. This approach reproduces the established collapse time of uniform density filaments and agrees well with our hydrodynamic simulations. In addition, we investigate the influence of different radial density profiles on the collapse. We find that the deviations compared to the uniform filament are less than 10%. Therefore, the analytic collapse model of the uniform density filament is an excellent general approach.

9 pages, 8 figures, published in MNRAS

References in corpus (15)

• On the Structure of the Orion A Cloud and the Formation of the Orion Nebula Cluster
• The Bones of the Milky Way
• Aspect Ratio Dependence of the Free-Fall Time for Non-Spherical Symmetries
• Investigating the Global Collapse of Filaments Using Smoothed Particle Hydrodynamics
• The Dynamical State fo the Starless Dense Core FeSt 1-457: A Pulsating Globule?
• The Dynamical State of the Starless Dense Core FeSt 1-457: A Pulsating Globule?
• Oscillations in the stable starless core Barnard 68
• Observational signatures of end-dominated collapse in the S242 filamentary structure
• Edge collapse and subsequent longitudinal accretion in Filament S242
• Star-forming sites IC 446 and IC 447: an outcome of end-dominated collapse of Monoceros R1 filament
• Accretion driven turbulence in filaments II: Effects of self-gravity
• Dissecting the super-critical filaments embedded in the 0.5 pc subsonic region of Barnard 5
• Merging Filaments I: A race against collapse
• Taking off the edge -- simultaneous filament and end core formation
• Star Formation in a Strongly Magnetized Cloud

Cited by in corpus (3)

• On the 3D Curvature and Dynamics of the Musca filament
• Filament fragmentation: Density gradients suppress end dominated collapse
• Revealing the Connection Between the Filamentary Hierarchy and Star Cluster Formation in a Simulated NGC 628 Galaxy