Taking off the edge -- simultaneous filament and end core formation

TL;DR

This paper investigates how simultaneous filament and core formation can prevent end cores from dominating in mass and density, aligning simulations more closely with observations of star-forming filaments.

Contribution

The study introduces a simulation setup with concurrent filament and core formation that reduces the dominance of end cores, improving understanding of core growth dynamics.

Findings

End cores move inward over time, reducing their dominance.

Density gradients outside cores soften gravitational acceleration.

Simultaneous formation leads to more uniform core development.

Abstract

Simulations of idealised star-forming filaments of finite length typically show core growth which is dominated by two cores forming at its respective end. The end cores form due to a strong increasing acceleration at the filament ends which leads to a sweep-up of material during the filament collapse along its axis. As this growth mode is typically faster than any other core formation mode in a filament, the end cores usually dominate in mass and density compared to other cores forming inside a filament. However, observations of star-forming filaments do not show this prevalence of cores at the filament ends. We explore a possible mechanism to slow the growth of the end cores using numerical simulations of simultaneous filament and embedded core formation, in our case a radially accreting filament forming in a finite converging flow. While such a setup still leads to end cores, they soon begin to move inwards and a density gradient is formed outside of the cores by the continued accumulation of material. As a result, the outermost cores are not longer located at the exact ends of the filament and the density gradient softens the inward gravitational acceleration of the cores. Therefore, the two end cores do not grow as fast as expected and thus do not dominate over other core formation modes in the filament.