Star formation from dense shocked regions in supersonic isothermal magneto-turbulence

TL;DR

This paper investigates how dense shock regions in supersonic isothermal magneto-turbulence can lead to star formation, highlighting the influence of magnetic field strength on collapse anisotropy and structure.

Contribution

It provides a detailed analysis of the structural properties of dense shocks in magneto-turbulence and their role as precursors to gravitational collapse, considering varying magnetic field strengths.

Findings

Weak magnetic fields lead to isotropic collapse.

Strong magnetic fields cause anisotropic collapse along field lines.

Dense shocks are associated with large-scale structures that persist for at least a free-fall time.

Abstract

Supersonic isothermal turbulence establishes a network of transient dense shocks that sweep up material and have a density profile described by balance between ram pressure of the background fluid versus the magnetic and gas pressure gradient behind the shock. These rare, densest regions of a turbulent environment can become Jeans unstable and collapse to form pre-stellar cores. Using numerical simulations of magneto-gravo-turbulence, we describe the structural properties of dense shocks, which are the seeds of gravitational collapse, as a function of magnetic field strength. In the regime of a weak magnetic field, the collapse is isotropic. Strong magnetic field strengths lead to significant anisotropy in the shocked distribution and collapse occurs preferentially parallel to the field lines. Our work provides insight into analyzing the magnetic field topology and density structures of young protostellar collapse, which the theory presented here predicts are associated with large-scale strong shocks that persist for at least a free-fall time.