2017ApJ...849...89M

We use CARMA 3 mm continuum and molecular lines (NH₂D, N₂H⁺, HCO⁺, HCN, and CS) at ∼1000 au resolution to characterize the structure and kinematics of the envelope surrounding the deeply embedded first core candidate Per-bolo 58. The line profile of the observed species shows two distinct peaks separated by 0.4-0.6 km s^–1, which most likely arise from two different optically thin velocity components rather than the product of self-absorption in an optically thick line. The two velocity components, each with a mass of ∼0.5-0.6 M_☉, overlap spatially at the position of the continuum emission and produce a general gradient along the outflow direction. We investigate whether these observations are consistent with infall in a turbulent and magnetized envelope. We compare the morphology and spectra of the N₂H⁺ (1-0) with synthetic observations of an MHD simulation that considers the collapse of an isolated core that is initially perturbed with a turbulent field. The proposed model matches the data in the production of two velocity components, traced by the isolated hyperfine line of the N₂H⁺ (1-0) spectra, and shows a general agreement in morphology and velocity field. We also use large maps of the region to compare the kinematics of the core with that of the surrounding large-scale filamentary structure and find that accretion from the large-scale filament could also explain the complex kinematics exhibited by this young dense core.