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Paper: |
Formation of Clouds via Thermal-Gravitational Instability in the Protogalactic Environment |
Volume: |
362, The Seventh Pacific Rim Conference on Stellar Astrophysics |
Page: |
290 |
Authors: |
Baek, C.H.; Ryu, D.; Kang, H.; Kim, J. |
Abstract: |
We study the formation of clouds via thermal-gravitational instability (TGI) in the protogalactic environment by carrying out three-dimensional hydrodynamic simulations. Simplified protogalactic halo and disk models were considered, wherein a gas of primordial composition evolves from initial density perturbations in a static frame and in a uniformly rotating frame, respectively. We find that virialized clouds of mass Mc ≥ 6 × 106 MSolar can form through gravitational merging in the protogalactic halo model. However, they acquire angular momentum corresponding to the mean spin parameter (λs) ~ 0.3, somewhat too large to become halo globular clusters. In the disk model with rotation comparable to the Galactic rotation at the Solar circle, the Coriolis force is not dynamically important during the early thermal instability stage but it suppresses gravitational infall and merging during late merging stages and disperses the gas to filamentary and sheet-like structures. We discuss the implications of our results for the formation of protoglobular cluster clouds (PGCCs) in the protogalactic environment. |
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