Dispersion of magnetic fields in molecular clouds. IV. Analysis of interferometry data

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 $\delta \simeq 19$ mpc, a ratio of turbulent-to-total magnetic energy $⟨B_t^2⟩/⟨B^2⟩\simeq 0.58$, and a magnetic field strength $B_0\sim 1.1mG;$ for W3 Main $\delta \simeq 22$ mpc, $⟨B_t^2⟩/⟨B^2⟩\simeq 0.74$, and $B_0\sim 0.7mG;$ while for DR21(OH) $\delta \simeq 12$ mpc, $⟨B_t^2⟩/⟨B^2⟩\simeq 0.70$, and $B_0\sim 1.2mG$.