Magnetically Dominated Parallel Interstellar Filaments at the Infrared Dark Cloud G14.225-0.506

Abstract

The G14.225-0.506 infrared dark cloud (IRDC G14.2) displays a remarkable complex of parallel dense molecular filaments projected on the plane of the sky. Previous dust emission and molecular-line studies have speculated whether magnetic fields could have played an important role in the formation of such long-shaped structures, which are hosts to numerous young stellar sources. In this work we have conducted a vast polarimetric survey at optical and near-infrared wavelengths in order to study the morphology of magnetic field lines in IRDC G14.2 through the observation of background stars. The orientation of interstellar polarization, which traces magnetic field lines, is perpendicular to most of the filamentary features within the cloud. Additionally, the larger-scale molecular cloud as a whole exhibits an elongated shape also perpendicular to magnetic fields. Estimates of magnetic field strengths indicate values in the range $320-550\mu$G, which allows sub-alfvénic conditions, but does not prevent the gravitational collapse of hub-filament structures, which in general are close to the critical state. These characteristics suggest that magnetic fields played the main role in regulating the collapse from large to small scales, leading to the formation of series of parallel elongated structures. The morphology is also consistent with numerical simulations that show how gravitational instabilities develop under strong magnetic fields. Finally, the results corroborate the hypothesis that a strong support from internal magnetic fields might explain why the cloud seems to be contracting on a time scale 2-3 times larger than what is expected from a free-fall collapse.

Accepted for publication at The Astrophysical Journal

References in corpus (21)

• The Critical Density and the Effective Excitation Density of Commonly Observed Molecular Dense Gas Tracers
• Filamentary structure of star-forming complexes
• Planck intermediate results. XIX. An overview of the polarized thermal emission from Galactic dust
• Tracing Magnetic Fields with Aligned Grains
• Magnetic Fields in the Formation of Sun-Like Stars
• Magnetic Fields in High-Mass Infrared Dark Clouds
• Magnetic Fields and Massive Star Formation
• Magnetically Regulated Star Formation in 3D: The Case of Taurus Molecular Cloud Complex
• The Efficiency of Grain Alignment in Dense Interstellar Clouds: A Reassessment of Constraints from Near Infrared Polarization
• Trigonometric parallaxes of star forming regions in the Sagittarius spiral arm
• The dynamical properties of dense filaments in the infrared dark cloud G035.39-00.33
• Optical polarimetry toward the Pipe nebula: Revealing the importance of the magnetic field
• On the radiation driven alignment of dust grains: Detection of the polarization hole in a starless core
• Magnetically Dominated Strands of Cold Hydrogen in the Riegel-Crutcher Cloud
• ALMA resolves the spiraling accretion flow in the luminous OB cluster forming region G33.92+0.11
• Aspect Ratio Dependence of the Free-Fall Time for Non-Spherical Symmetries
• Grain Alignment in Starless Cores
• SiO emission from low- and high-velocity shocks in Cygnus-X massive dense clumps
• Core and filament formation in magnetized, self-gravitating isothermal layers
• Shaping a high-mass star-forming cluster through stellar feedback. The case of the NGC 7538 IRS 1-3 complex
• A young stellar cluster within the RCW41 HII region: deep NIR photometry and Optical/NIR polarimetry

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