Multi-scale physical properties of NGC 6334 as revealed by local relative orientations between magnetic fields, density gradients, velocity gradients, and gravity

Abstract

We present ALMA dust polarization and molecular line observations toward 4 clumps (I(N), I, IV, and V) in the massive star-forming region NGC 6334. In conjunction with large-scale dust polarization and molecular line data from JCMT, Planck, and NANTEN2, we make a synergistic analysis of relative orientations between magnetic fields (${\theta }_{\mathrm{B}}$), column density gradients (${\theta }_{\mathrm{NG}}$), local gravity (${\theta }_{\mathrm{LG}}$), and velocity gradients (${\theta }_{\mathrm{VG}}$) to investigate the multi-scale (from $\sim$30 pc to 0.003 pc) physical properties in NGC 6334. We find that the relative orientation between ${\theta }_{\mathrm{B}}$ and ${\theta }_{\mathrm{NG}}$ changes from statistically more perpendicular to parallel as column density ($N_{{\mathrm{H}}_2}$) increases, which is a signature of trans-to-sub-Alfvénic turbulence at complex/cloud scales as revealed by previous numerical studies. Because ${\theta }_{\mathrm{NG}}$ and ${\theta }_{\mathrm{LG}}$ are preferentially aligned within the NGC 6334 cloud, we suggest that the more parallel alignment between ${\theta }_{\mathrm{B}}$ and ${\theta }_{\mathrm{NG}}$ at higher $N_{{\mathrm{H}}_2}$ is because the magnetic field line is dragged by gravity. At even higher $N_{{\mathrm{H}}_2}$, the angle between ${\theta }_{\mathrm{B}}$ and ${\theta }_{\mathrm{NG}}$ or ${\theta }_{\mathrm{LG}}$ transits back to having no preferred orientation or statistically slightly more perpendicular, suggesting that the magnetic field structure is impacted by star formation activities. A statistically more perpendicular alignment is found between ${\theta }_{\mathrm{B}}$ and ${\theta }_{\mathrm{VG}}$ throughout our studied $N_{{\mathrm{H}}_2}$ range, which indicates a trans-to-sub-Alfvénic state at small scales as well. The normalised mass-to-flux ratio derived from the polarization-intensity gradient (KTH) method increases with $N_{{\mathrm{H}}_2}$.

35 pages, 18 figures. Accepted by ApJ

References in corpus (27)

• Theory of Star Formation
• MAMBO Mapping of Spitzer c2d Small Clouds and Cores
• Radiative torques: Analytical Model and Basic Properties
• Tracing Magnetic Fields with Aligned Grains
• Magnetic Fields and Massive Star Formation
• Placing Confidence Limits on Polarization Measurements
• Trigonometric parallaxes of star forming regions in the Sagittarius spiral arm
• Velocity Gradients as a Tracer for Magnetic Fields
• Interferometric observations of magnetic fields in forming stars
• Tracing interstellar magnetic field using velocity gradient technique: Application to Atomic Hydrogen data
• Gravity Driven Magnetic Field at ~1000 au Scales in High-mass Star Formation
• Submillimeter and Far-Infrared Polarimetric Observations of Magnetic Fields in Star-Forming Regions
• Dust polarized emission observations of NGC 6334; BISTRO reveals the details of the complex but organized magnetic field structure of the high-mass star-forming hub-filament network
• Interferometric multi-wavelength (sub)millimeter continuum study of the young high-mass protocluster IRAS05358+3543
• Gravity, Magnetic Field, and Turbulence: Relative Importance and Impact on Fragmentation in the Infrared Dark Cloud G34.43+00.24
• Magnetic Field Morphology in Interstellar Clouds with the Velocity Gradient Technique
• Magnetic fields in star formation: a complete compilation of all the DCF estimations
• Massive Clumps in the NGC 6334 Star Forming Region
• Magnetic field properties in star formation: a review of their analysis methods and interpretation
• B-fields in Star-Forming Region Observations (BISTRO): Magnetic Fields in the Filamentary Structures of Serpens Main
• Magnetic field strength from turbulence theory (I): Using differential measure approach (DMA)
• Magnetic Fields in Massive Star-Forming Regions (MagMaR) II. Tomography Through Dust and Molecular Line Polarization in NGC 6334I(N)
• Magnetized converging flows towards the hot core in the intermediate/high-mass star-forming region NGC 6334 V
• The role of the magnetic field in the fragmentation process: the case of G14.225-0.506
• Velocity structure of the 50 pc-long NGC 6334 filamentary cloud: Hints of multiple compressions and their impact on the cloud properties?
• Alignment of the magnetic field in star forming regions and why it might be difficult to observe
• 654 GHz Continuum and C18O (6-5) Observations of G240.31+0.07 with the Submillimeter Array

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