Revisiting the Magnetic Field of the L183 Starless Core

TL;DR

This study uses polarization observations at 850 μm to map the magnetic field in the starless core L183, revealing that magnetic forces are strong enough to prevent gravitational collapse, thus influencing star formation.

Contribution

The paper provides new magnetic field strength measurements in L183 using POL-2 data and the Davis-Chandrasekhar-Fermi method, confirming the magnetic support in a starless core.

Findings

Magnetic field strengths range from ~120 to ~270 μG.

All sub-regions are magnetically subcritical.

Magnetic fields oppose gravitational collapse.

Abstract

We present observations of linear polarization from dust thermal emission at 850 $\mu m$ towards the starless cloud L183. These data were obtained at the James Clerk Maxwell Telescope (JCMT) using the Submillimetre Common-User Bolometer Array 2 (SCUBA-2) camera in conjunction with its polarimeter POL-2. Polarized dust emission traces the plane-of-sky magnetic field structure in the cloud, thus allowing us to investigate the role of magnetic fields in the formation and evolution of its starless core. To interpret these measurements, we first calculate the dust temperature and column density in L183 by fitting the spectral energy distribution obtained by combining data from the JCMT and the $\textit{Herschel}$ space observatory. We used the Davis-Chandrasekhar-Fermi technique to measure the magnetic field strength in five sub-regions of the cloud, and we find values ranging from $\sim120\pm18~\mu G$ to $\sim270\pm64~\mu G$ in agreement with previous studies. Combined with an average hydrogen column density ($N_{\text{H}_2}$) of $\sim 1.5 \times 10^{22} $cm$^{-2}$ in the cloud, we also find that all five sub-regions are magnetically subcritical. These results indicate that the magnetic field in L183 is sufficiently strong to oppose the gravitational collapse of the cloud.