Probing the Conditions for the Atomic-to-Molecular Transition in the Interstellar Medium
Abstract
We examine the physical conditions required for the formation of H2 in the solar neighborhood by comparing H I emission and absorption spectra toward 58 lines of sight at b < −5∘ to CO(1-0) and dust data. Our analysis of CO-associated cold and warm neutral medium (CNM and WNM) shows that the formation of CO-traced molecular gas is favored in regions with high column densities where the CNM becomes colder and more abundant. In addition, our comparison to the one-dimensional steady-state H I-to-H2 transition model of Bialy et al. (2016) suggests that only a small fraction of the clumpy CNM participates in the formation of CO-traced molecular gas. Another possible interpretation would be that missing physical and chemical processes in the model could play an important role in H2 formation.
- Publication:
-
Resolving the Rise and Fall of Star Formation in Galaxies
- Pub Date:
- 2023
- DOI:
- 10.1017/S1743921322004896
- Bibcode:
- 2023IAUS..373...81P
- Keywords:
-
- ISM: atoms;
- ISM: clouds;
- dust;
- extinction;
- ISM: molecules;
- ISM: structure;
- radio lines: ISM