Revisiting the Magnetic Field of the L183 Starless Core

Abstract

Abstract We present observations of linear polarization from dust thermal emission at 850 μm toward the starless cloud L183. These data were obtained at the James Clerk Maxwell Telescope (JCMT) using the 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 Herschel space observatory. We used the Davis–Chandrasekhar–Fermi technique to measure the magnetic field strength in five subregions of the cloud, and we find values ranging from ∼120 ± 18 μG to ∼270 ± 64 μG in agreement with previous studies. Combined with an average hydrogen column density ( ) of ∼1.5 × 1022 cm−2 in the cloud, we also find that all five subregions are magnetically subcritical. These results indicate that the magnetic field in L183 is sufficiently strong to oppose the gravitational collapse of the cloud.