Dispersion of Magnetic Fields in Molecular Clouds. IV - Analysis of Interferometry Data

Abstract

We expand on the dispersion analysis of polarimetry maps toward applications to interferometry data. We show how the filtering of low-spatial frequencies can be accounted for within the idealized Gaussian turbulence model, initially introduced for single-dish data analysis, to recover reliable estimates for correlation lengths of magnetized turbulence, as well as magnetic field strengths (plane-of-the-sky component) using the Davis-Chandrasekhar-Fermi method. We apply our updated technique to TADPOL/CARMA data obtained on W3(OH), W3 Main, and DR21(OH). For W3(OH) our analysis yields a turbulence correlation length $\hat{I}´\simeq 19$ mpc, a ratio of turbulent-to-total magnetic energy $⟨B_{\mathrm{t}}^2⟩/⟨B^2⟩\simeq 0.58$, and a magnetic field strength $B_0\sim 1.1\mathrm{mG}$; for W3 Main $\hat{I}´\simeq 22$ mpc, $⟨B_{\mathrm{t}}^2⟩/⟨B^2⟩\simeq 0.74$, and $B_0\sim 0.7\mathrm{mG}$; while for DR21(OH) $\hat{I}´\simeq 12$ mpc, $⟨B_{\mathrm{t}}^2⟩/⟨B^2⟩\simeq 0.70$, and $B_0\sim 1.2\mathrm{mG}$.

27 pages, 9 figures, 2 tables; accepted for ApJ