Speaker
Description
In typical star forming galaxies, cooling is dominated by fine-structure metal lines where H₂ formation occurs predominantly via the dust channel. However, in dwarf galaxies with extremely low metallicity, cooling and chemistry behave qualitatively differently. In this study, we perform high-resolution hydrodynamic simulations using the GIZMO code to investigate the thermal balance of the interstellar medium (ISM) in dwarf galaxies. Our results demonstrate that H₂ cannot form without the gas-phase channel at Z < 1e-3 Z_sun, which leads to a complete dearth of cold gas. Conversely, when H₂ gas-phase formation is included, H₂ cooling emerges as the dominant cooling mechanism despite the low H₂ abundances, surpassing metal fine-structure lines, changing the thermal structure of the ISM. Furthermore, the classical two-phase ISM structure disappears in the low-metallicity dwarf galaxies, leading to a single-phase ISM with only a trace of cold gas.
| Participate the oral/poster presentation award competition | Yes |
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