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

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 ∼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 multicomponent 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 ∼0.03 pc. The velocity dispersion profiles of the filaments also show decreasing trends toward the filament spines. Moreover, the velocity gradient field in B5 appears to be locally well ordered (∼0.04 pc) but globally complex, with kinematic behaviors suggestive of inhomogeneous turbulent accretion onto filaments and longitudinal flows toward a local overdensity along one of the filaments.