Synthetic Observations of Magnetic Fields in Protostellar Cores

Abstract

The role of magnetic fields in the early stages of star formation is not well constrained. In order to discriminate between different star formation models, we analyze 3D magnetohydrodynamic simulations of low-mass cores and explore the correlation between magnetic field orientation and outflow orientation over time. We produce synthetic observations of dust polarization at resolutions comparable to millimeter-wave dust polarization maps observed by CARMA and compare these with 2D visualizations of projected magnetic field and column density. Cumulative distribution functions of the projected angle between the magnetic field and outflow show different degrees of alignment in simulations with differing mass-to-flux ratios. The distribution function for the less magnetized core agrees with observations finding random alignment between outflow and field orientations, while the more magnetized core exhibits stronger alignment. We find that fractional polarization increases when the system is viewed such that the magnetic field is close to the plane of the sky, and the values of fractional polarization are consistent with observational measurements. The simulation outflow, which reflects the underlying angular momentum of the accreted gas, changes direction significantly over the first $\sim 0.1$ Myr of evolution. This movement could lead to the observed random alignment between outflows and the magnetic fields in protostellar cores.

14 pages, 10 figures, 1 appendix, accepted for publication in the Astrophysical Journal

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Cited by in corpus (20)

• The Physics of Star Cluster Formation and Evolution
• Interferometric observations of magnetic fields in forming stars
• ALMA observations of dust polarization and molecular line emission from the Class 0 protostellar source Serpens SMM1
• Unveiling the Role of the Magnetic Field at the Smallest Scales of Star Formation
• Alignment Between Protostellar Outflows and Filamentary Structure
• The Formation and Evolution of Wide-Orbit Stellar Multiples In Magnetized Clouds
• Zooming in on Individual Star Formation: Low- and High-mass Stars
• Formation of Wide Binaries by Turbulent Fragmentation
• The JCMT BISTRO survey: alignment between outflows and magnetic fields in dense cores/clumps
• ALMA observations reveal no preferred outflow--filament and outflow--magnetic field orientations
• The CARMA-NRO Orion Survey: Protostellar Outflows, Energetics, and Filamentary Alignment
• Physical properties of accretion shocks toward the Class I protostellar system Oph-IRS 44
• Transport of Protostellar Cosmic Rays in Turbulent Dense Cores
• A turbulent origin for the complex envelope kinematics in the young low-mass core Per-Bolo 58
• Alignment of dense molecular core morphology and velocity gradients with ambient magnetic fields
• A Census of Outflow to Magnetic Field Orientations in Nearby Molecular Clouds
• Outflows, cores and magnetic field orientations in W43-MM1 as seen by ALMA
• The Transition of Polarized Dust Thermal Emission from the Protostellar Envelope to the Disk Scale
• The kinematics of the magnetised protostellar core IRAS15398-3359
• Magnetic field alignment with dense cores in the transition between cloud and core scales