EPoS Contribution
EPoS Contribution
Formation of Magnetized Prestellar Cores in Turbulent Clouds

Che-Yu Chen
UVA, Charlottesville, US
We showed in three-dimensional, turbulent MHD simulations that in typical GMC environments, the turbulence-compressed regions are strongly-magnetized sheet-like layers, within which dense filaments and embedded self-gravitating cores form via gathering material along the magnetic field lines. From our simulations, we identified hundreds of self-gravitating cores with masses, sizes, mass-to-magnetic flux ratios, and specific angular momenta comparable to observations. We found that core masses and sizes do not depend on the coupling strength between neutrals and ions, and ambipolar diffusion is not necessary to form low- mass supercritical cores. This is a result of anisotropic contraction along field lines, which can explain the fact that magnetically supercritical cores are commonly observed even in a strongly magnetized medium. We then confirmed the anisotropic core formation model in simulations with extended parameter space, and quantified how core properties depend on the pre-shock inflow velocity and upstream magnetic field strength. Our studies also suggest that cores acquire angular momentum from small-scale turbulence, which is independent in direction from the local magnetic field. As a result, the core's rotation axis would be poorly aligned with its mean magnetic field, presumably enabling the formation of protostellar disks by reducing the magnetic braking efficiency.
Caption: Summary of simulated core statistical properties for models with different inflow Mach numbers (top row) and cloud magnetic fields (bottom row), with theoretical predictions from anisotropic core formation model (dotted lines). The dashed lines in the core size plots (second column) indicate the resolution of our simulations.
E. Ostriker, Princeton U, US
Key publication

Suggested Session: Cores and Collapse