GBT24B-167
Resolving the turbulence-deficient molecular clouds in the outer Galaxy
Abstract
Surveys of molecular gas in the Solar neighbourhood and the inner Galaxy have shown that molecular clouds are statistically equilibrium between the turbulent kinetic energy (E_k) and the self-gravitational energy (E_g), namely the virial parameter alpha_vir=2E_k/|E_g|~1. However, our recent work shows that alpha_vir decreases towards the metal-poor outer Galaxy and is systematically smaller than unity at Galactocentric radii Rgc > 15 kpc. This suggests that turbulence is insufficient to support against the cloud's self-gravity in such conditions. Nevertheless, the current data can not resolve the detailed cloud structure, leading to uncertainties in estimating |E_g| and inability to decompose the possible substructures. Therefore, we propose GBT/Argus observations towards seven clouds at Rgc > 15 kpc, targeting the 13CO J=1-0 line. With a ~0.5 pc resolution, the morphology and the velocity fields are key to understanding the low virial parameters and possible star formation activities in metal-poor molecular clouds from the outer disk of the Milky Way.
Investigators
| Name | Institution |
|---|---|
| Lingrui Lin * | Nanjing University |
| Gan Luo | Institut de Radio Astronomique Millimétrique |
| Zhiyu zhang | Nanjing University |
| Junzhi Wang | Purple Mountain Observatory, CAS; Shanghai Astronomical Observatory, CAS; Nanjing University; Guangxi University |
| Yichen Sun | Nanjing University |
| Di Li | National Astronomical Observatories, CAS; Space Science Institute |
| Jialu Li | Maryland, University of |
| Siyi Feng | Max-Planck-Institut für extraterrestrische Physik; Max-Planck-Institut für Astronomie; National Astronomical Observatory of Japan ; Xiamen University; East Asian Observatory |
| Hauyu Liu | Academia Sinica; European Southern Observatory; National Sun Yat-sen University |
| yan sun | Purple Mountain Observatory, CAS |
| Yong Shi | Nanjing University |
| Yan Gong | Max-Planck-Institut für Radioastronomie; Purple Mountain Observatory, CAS |
| Thomas Bisbas | Köln, Universität zu |
* indicates the PI