Turbulence and Accretion: a High-resolution Study of the B5 Filaments

TL;DR

This study provides high-resolution kinematic analysis of B5 filaments, revealing their structure, width, and complex turbulent accretion processes, supporting theories of filament formation at the sonic scale.

Contribution

It offers the first detailed kinematic profile of B5 filaments at 0.009 pc resolution, linking filament properties with turbulent compression models.

Findings

Filaments have FWHM widths of ~0.03 pc.

Velocity dispersion decreases towards filament spines.

Kinematic behavior indicates inhomogeneous turbulent accretion.

Abstract

High-resolution observations of the Perseus B5 "core" have previously revealed that this subsonic region actually consists of several filaments that are likely in the process of forming a quadruple stellar system. Since subsonic filaments are thought to be produced at the $\sim 0.1$ pc sonic scale by turbulent compression, a detailed kinematic study is crucial to test such a scenario in the context of core and star formation. Here we present a detailed kinematic follow-up study of the B5 filaments at a 0.009 pc resolution using the VLA and GBT combined observations fitted with multi-component spectral models. Using precisely identified filament spines, we find a remarkable resemblance between the averaged width profiles of each filament and Plummer-like functions, with filaments possessing FWHM widths of $\sim 0.03$ pc. The velocity dispersion profiles of the filaments also show decreasing trends towards the filament spines. Moreover, the velocity gradient field in B5 appears to be locally well ordered ($\sim 0.04$ pc) but globally complex, with kinematic behaviors suggestive of inhomogeneous turbulent accretion onto filaments and longitudinal flows towards a local overdensity along one of the filaments.