Magnetic Fields in Star Formation Regions: 1.3 Millimeter Continuum Polarimetry

Abstract

We present a nine-point λ=1.3 mm continuum polarization map of the inner arcminute of the DR 21 cloud core. The polarization and position angles are very uniform, and the inferred magnetic field (P.A.~75°) is nearly orthogonal to the cloud elongation (P.A.~7°). Applying the virial theorem and comparing the continuum polarimetry, we find that the magnetic field strength must be greater than a few mG to have a significant impact. Turbulent gas motions are probably a more significant source of support against self-gravity in the cloud core than in the magnetic field.