Dispersion of Magnetic Fields in Molecular Clouds. II

TL;DR

This paper refines methods to analyze magnetic field dispersion in molecular clouds by accounting for observational effects and applying the approach to OMC-1, revealing key magnetic properties.

Contribution

It introduces a new way to incorporate signal integration effects and estimate the turbulent magnetic field correlation scale from polarization data.

Findings

Turbulent correlation length in OMC-1 is about 16 mpc.

Turbulent to large-scale magnetic field ratio is approximately 0.5.

Large-scale magnetic field strength in OMC-1 is about 0.76 mG.

Abstract

We expand our study on the dispersion of polarization angles in molecular clouds. We show how the effect of signal integration through the thickness of the cloud as well as across the area subtended by the telescope beam inherent to dust continuum measurements can be incorporated in our analysis to correctly account for its effect on the measured angular dispersion and inferred turbulent to large-scale magnetic field strength ratio. We further show how to evaluate the turbulent magnetic field correlation scale from polarization data of sufficient spatial resolution and high enough spatial sampling rate. We apply our results to the molecular cloud OMC-1, where we find a turbulent correlation length of approximately 16 mpc, a turbulent to large-scale magnetic field strength ratio of approximately 0.5, and a plane-of-the-sky large-scale magnetic field strength of approximately 0.76 mG.