Magnetic Field of Molecular Gas Measured with the Velocity Gradient Technique I. Orion A

Abstract

Magnetic fields play an important role in the evolution of molecular clouds and star formation. Using the Velocity Gradient Technique (VGT) model, we measured the magnetic field in Orion A using the 12CO, 13CO, and C18O (1-0) emission lines at a scale of 0.07 pc. The measured B-field shows an east-west orientation that is perpendicular to the integral shaped filament of Orion A at large scale. The VGT magnetic fields obtained from 13CO and C18O are in agreement with the B-field that is measured from the Planck 353 GHz dust polarization at a scale of 0.55 pc. Removal of density effects by using a Velocity Decomposition Algorithm can significantly improve the accuracy of the VGT in tracing magnetic fields with the 12CO (1-0) line. The magnetic field strength of seven sub-clouds, OMC-1, OMC-2, OMC-3, OMC-4, OMC-5, L 1641-N, and NGC 1999 has also been estimated with the Davis-Chandrasekhar-Fermi (DCF) and MM2 technique, and these are found to be in agreement with previous results obtained from dust polarization at far-infrared and sub-millimeter wavelengths. At smaller scales, the VGT proves a good method to measure magnetic fields.

15 pages, 6 figures, accepted to ApJ

References in corpus (17)

• The NumPy array: a structure for efficient numerical computation
• Theory of Star Formation
• The distance to the Orion Nebula
• The Critical Density and the Effective Excitation Density of Commonly Observed Molecular Dense Gas Tracers
• Molecular Hydrogen and Global Star Formation Relations in Galaxies
• The Gould's Belt Distances Survey (GOBELINS) II. Distances and structure towards the Orion Molecular Clouds
• The JCMT BISTRO Survey: The magnetic field strength in the Orion A filament
• Velocity Gradients as a Tracer for Magnetic Fields
• Tracing interstellar magnetic field using velocity gradient technique: Application to Atomic Hydrogen data
• Gravity, Magnetic Field, and Turbulence: Relative Importance and Impact on Fragmentation in the Infrared Dark Cloud G34.43+00.24
• Magnetic fields in star formation: a complete compilation of all the DCF estimations
• Revealing Gravitational Collapse in Serpens G3-G6 Molecular Cloud using Velocity Gradients
• Technique for separating velocity and density contributions in spectroscopic data and its application to studying turbulence and magnetic fields
• Kinetic temperature of massive star-forming molecular clumps measured with formaldehyde. III. The Orion Molecular Cloud 1
• Bird's eye view of molecular clouds in the Milky Way: I. Column density and star formation from sub-pc to kpc scales
• Evidence for dense gas heated by the explosion in Orion KL
• Magnetic field structure of OMC-3 in the far infrared revealed by SOFIA/HAWC+

Cited by in corpus (3)

• Role of magnetic fields in fueling Seyfert nuclei
• The Impact of Expanding HII Regions on Filament G37:Curved Magnetic Field and Multiple Direction Material Flows
• Parallel and Perpendicular Alignments of Velocity Gradient and Magnetic Field observed in the Molecular Clouds L1478 and L1482