Characterizing the magnetic fields of nearby molecular clouds using submillimeter polarization observations

Journal Article · Tue Mar 16 00:00:00 EDT 2021 · Monthly Notices of the Royal Astronomical Society

DOI:https://doi.org/10.1093/mnras/stab596· OSTI ID:1813708

Sullivan, Colin H. ^[1]; Fissel, L. M. ^[2]; King, P. K. ^[3]; Chen, C-Y ^[4]; Li, Z-Y ^[5]; Soler, J. D. ^[6]

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1. Univ. of Virginia, Charlottesville, VA (United States). Dept. of Astronomy; National Radio Astronomy Observatory, Charlottesville, VA (United States)
2. National Radio Astronomy Observatory, Charlottesville, VA (United States); Queen's Univ., Kingston, ON (Canada). Dept. of Physics, Engineering Physics, and Astronomy
3. Univ. of Virginia, Charlottesville, VA (United States). Dept. of Astronomy; Johns Hopkins Univ., Laurel, MD (United States). Applied Physics Laboratory; Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
4. Univ. of Virginia, Charlottesville, VA (United States). Dept. of Astronomy; Johns Hopkins Univ., Laurel, MD (United States). Applied Physics Laboratory
5. Univ. of Virginia, Charlottesville, VA (United States). Dept. of Astronomy
6. Max Planck Institute for Astronomy, Heidelberg (Germany)

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 (N_H) 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.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
• Sponsoring Organization: AUI; NSF; National Radio Astronomy Observatory; USDOE National Nuclear Security Administration (NNSA); University of Virginia
• Grant/Contract Number: AC52-07NA27344
• OSTI ID: 1813708
• Report Number(s): LLNL-JRNL--785178; 978367
• Journal Information: Monthly Notices of the Royal Astronomical Society, Journal Name: Monthly Notices of the Royal Astronomical Society Journal Issue: 4 Vol. 503; ISSN 0035-8711
• Publisher: Royal Astronomical Society
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
Clouds
ISM
Magnetic Fields
Polarization