High-mass Starless Clumps: Dynamical State and Correlation between Physical Parameters

In order to study the initial conditions of massive star formation, we have previously built a sample 463 high-mass starless clumps (HMSCs) across inner Galactic plane covered by multiple continuum surveys. Here, use $^{13}$ CO(2-1) line data from SEDIGISM survey, which covers 78$^{\circ}$ in longitude ($-60^{\circ}<l<18^{\circ}$, $\vert b\vert<0.5^{\circ}$) with 30$^{\prime \prime}$ resolution, investigate global dynamical state these parsec-scale HMSCs (207 sources good quality data, mass $10^{2}\sim 10^{5}\ \rm M_{\odot}$, size $0.1\sim3.6$ pc). We find that most are highly turbulent median Mach number $\mathcal{M_{S}}\sim$ 8.2, and 44\%$\sim$55\% them gravitationally bound (with virial parameter $\alpha_{\rm vir} \lesssim 2$) if no magnetic fields were present. A field strength 0.33$\sim$0.37 mG would be needed support against collapse, agreement previous observations formation regions. Luminosity-to-mass ratio, an important tracer for evolutionary stage, is strongly correlated dust temperature. Magnetic also density. The Larson linewidth-size scaling does not hold HMSCs. This advances our understanding properties HMSCs, high-resolution ALMA on way resolved properties.