What role of gravity, turbulence and magnetic fields in high-mass star formation clouds?

TL;DR

This study analyzes how gravity, turbulence, and magnetic fields influence high-mass star formation by examining velocity and density scalings, revealing a state of near-virial equilibrium and a specific turbulent energy spectrum.

Contribution

It provides new observational evidence on the scalings and energy spectrum in high-mass star formation clouds, highlighting the interplay of gravity, turbulence, and magnetic fields.

Findings

Velocity dispersion scales as L^{0.26}

Density scales as L^{-1.54}

Turbulent energy spectrum follows E(k) ∝ k^{-1.52}

Abstract

To explore the potential role of gravity, turbulence and magnetic fields in high-mass star formation in molecular clouds, this study revisits the velocity dispersion--size ($\sigma$--$L$) and density--size ($\rho$--$L$) scalings and the associated turbulent energy spectrum using an extensive data sample. The sample includes various hierarchical density structures in high-mass star formation clouds, across scales of 0.01 to 100 pc. We observe $\sigma \propto L^{0.26}$ and $\rho \propto L^{-1.54}$ scalings, converging toward a virial equilibrium state. A nearly flat virial parameter--mass ($\alpha_{\rm vir}-M$) distribution is seen across all density scales, with $\alpha_{\rm vir}$ values centered around unity, suggesting a global equilibrium maintained by the interplay between gravity and turbulence across multiple scales. Our turbulent energy spectrum ($E(k)$) analysis, based on the $\sigma$--$L$ and $\rho$--$L$ scalings, yields a characteristic $E(k) \propto k^{-1.52}$. These findings indicate the potential significance of gravity, turbulence, and possibly magnetic fields all in regulating dynamics of molecular clouds and high-mass star formation therein.