Surveys of clumps, cores, and condensations in Cygnus X: Temperature and nonthermal velocity dispersion revealed by VLA NH3 observations

• DOI: 10.48550/arxiv.2403.03845
• Publication Date: 2024-03-06
• Authors: Xu Zhang; Keping Qiu; Qizhou Zhang; Yue Cao; Yu Cheng; Junhao Liu; Yuwei Wang; Xing Lu; Xing Pan
• Keywords: Velocity dispersion

The physical properties, evolution, and fragmentation of massive dense cores (MDCs, $\sim$ 0.1 pc) are fundamental pieces in our understanding high-mass star formation. We aim to characterize the temperature, velocity dispersion, MDCs Cygnus X giant molecular cloud investigate stability dynamics these cores. present Karl G. Jansky Very Large Array (VLA) observations NH$_3$ (J,K) = (1,1) (2,2) inversion lines towards 35 X, from which we calculated temperature dispersion. extracted 202 fragments ($\sim$ 0.02 moment-0 maps with GAUSSCLUMPS algorithm. analyzed their through evaluating corresponding kinetic, gravitational potential, magnetic energies virial parameters. have a typical mean kinetic T$_K$ 20 K. Our analysis shows that many subvirialized states, indicating energy is insufficient support against gravity. nonthermal dispersions most at transonic mildly supersonic levels, bulk motions make only minor contribution Regarding fragments, 19 K, mostly trans-sonic subsonic. Unless there strong field, probably not virialized states. also find dynamically quiescent, while few active due formation activity.