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

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 (${\alpha }_{\mathrm{v}\mathrm{i}\mathrm{r}}-M$) distribution is seen across all density scales, with ${\alpha }_{\mathrm{v}\mathrm{i}\mathrm{r}}$ 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.