Of all the factors that influence star formation, magnetic fields are perhaps the least well understood. The goal of this paper is to characterize the 3D magnetic field properties of nearby molecular clouds through various methods of statistically analysing maps of polarized dust emission. Our study focuses on nine clouds, with data taken from the Planck Sky Survey as well as data from the Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry observations of Vela C. We compare the distributions of polarization fraction (p), dispersion in polarization angles ($\mathcal {S}$), and hydrogen column density (NH) for each of our targeted clouds. To broaden the scope of our analysis, we compare the distributions of our clouds’ polarization observables with measurements from synthetic polarization maps generated from numerical simulations. We also use the distribution of polarization fraction measurements to estimate the inclination angle of each cloud’s cloud-scale magnetic field. We obtain a range of inclination angles associated with our clouds, varying from 16○ to 69○. We establish inverse correlations between p and both $\mathcal {S}$ and NH in almost every cloud, but we are unable to establish a statistically robust $\mathcal {S}$ versus NH trend. By comparing the results of these different statistical analysis techniques, we are able to propose a more comprehensive view of each cloud’s 3D magnetic field properties. These detailed cloud analyses will be useful in the continued studies of cloud-scale magnetic fields and the ways in which they affect star formation within these molecular clouds.

中文翻译：

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使用亚毫米偏振观测表征附近分子云的磁场

在影响恒星形成的所有因素中，磁场可能是最不为人所知的。本文的目的是通过各种统计分析极化尘埃发射图的方法来表征附近分子云的 3D 磁场特性。我们的研究集中在九个云上，数据来自普朗克巡天以及来自气球载大口径亚毫米望远镜的数据，用于对 Vela C 进行偏振观测。我们比较了偏振分数 (p) 的分布、偏振角的色散($\mathcal {S}$) 和每个目标云的氢柱密度 (NH)。为了扩大我们的分析范围，我们将云的偏振观测分布与数值模拟生成的合成偏振图的测量值进行了比较。我们还使用极化分数测量的分布来估计每个云的云级磁场的倾角。我们获得了与我们的云相关的一系列倾角，从 16○ 到 69○ 不等。我们在几乎所有云中都建立了 p 与 $\mathcal {S}$ 和 NH 之间的反相关，但我们无法建立统计上稳健的 $\mathcal {S}$ 与 NH 趋势。通过比较这些不同统计分析技术的结果，我们能够更全面地了解每个云的 3D 磁场特性。这些详细的云分析将有助于继续研究云尺度磁场以及它们影响这些分子云中恒星形成的方式。