The magnetic field in quiescent star-forming filament G16.96+0.27

TL;DR

This study maps the magnetic field in a quiescent star-forming filament, revealing its strength, orientation, and role in cloud stability, suggesting a state close to equilibrium with potential fragmentation indicators.

Contribution

First detailed magnetic field mapping of G16.96+0.27 using JCMT/POL-2, providing insights into magnetic influence on filament stability and structure.

Findings

Magnetic field roughly perpendicular to filament structure.

Magnetic field strength estimated at ~96 μG.

Cloud is in a quasi-equilibrium state with gravity, magnetic field, and turbulence.

Abstract

We present 850 {\mu}m thermal dust polarization observations with a resolution of 14.4"(~ 0.13 pc) towards an infrared dark cloud G16.96+0.27 using JCMT/POL-2. The average magnetic field orientation, which roughly agrees with the larger-scale magnetic field orientation traced by the Planck 353 GHz data, is approximately perpendicular to the filament structure. The estimated plane-of-sky magnetic field strength is ~ 96 {\mu}G and ~ 60 {\mu}G using two variants of the Davis-Chandrasekhar-Fermi methods. We calculate the virial and magnetic critical parameters to evaluate the relative importance of gravity, the magnetic field, and turbulence. The magnetic field and turbulence are both weaker than gravity, but magnetic fields and turbulence together are equal to gravity, suggesting that G16.96+0.27 is in a quasi-equilibrium state. The cloud-magnetic-field alignment is found to have a trend moving away from perpendicularity in the dense regions, which may serve as a tracer of potential fragmentation in such quiescent filaments.