Physical Properties and HI-to-H2 Transition Across Taurus Linear Edge
Fuente:
arXiv
Guardado en:
| Autores principales: | , , , , , , , |
|---|---|
| Formato: | Preprint |
| Publicado: |
2025
|
| Materias: | |
| Acceso en línea: | |
| Etiquetas: |
Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
|
| _version_ | 1866908296017870848 |
|---|---|
| author | Tang, Ningyu Miao, Feihang Luo, Gan Li, Di Wang, Junzhi Du, Fujun Wu, Donghong Liu, Shu |
| author_facet | Tang, Ningyu Miao, Feihang Luo, Gan Li, Di Wang, Junzhi Du, Fujun Wu, Donghong Liu, Shu |
| contents | Studying the atomic-to-molecular transition is essential for understanding the evolution of interstellar medium. The linear edge of Taurus molecular cloud, clearly identified in the $^{13}$CO(1-0) intensity map, serves as an ideal site for investigating this transition. Utilizing the Arizona Radio Observatory Sub-Millimeter Telescope, we obtained mapping observations of CO(2-1), $^{13}$CO(2-1), and CO(3-2) across this linear edge. The intensity ratio between CO(2-1) and $^{13}$CO(2-1) indicates a lower limit of the $^{12}C/^{13}C$ ratio of $54\pm 17$. Based on multi-transition observations of CO and $^{13}$CO, we performed Markov Chain Monte Carlo (MCMC) fit of the physical properties across this edge using non-Local Thermodynamic Equilibrium analysis with the RADEX code, based on the Large velocity Gradient (LVG) assumption. The number density profile exhibits a pronounced jump coinciding with the H$_2$ infrared emission peak. The cold HI gas within the molecular cloud, manifested as HI-Narrow Self-Absorption (HINSA) features, is detected along the cloud edge. Our quantitative comparison with numerical simulations provides tentative evidence that shocks induced by colliding gas flows may contribute to the atomic-to-molecular phase transition observed along the linear edge. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2504_01299 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Physical Properties and HI-to-H2 Transition Across Taurus Linear Edge Tang, Ningyu Miao, Feihang Luo, Gan Li, Di Wang, Junzhi Du, Fujun Wu, Donghong Liu, Shu Astrophysics of Galaxies Studying the atomic-to-molecular transition is essential for understanding the evolution of interstellar medium. The linear edge of Taurus molecular cloud, clearly identified in the $^{13}$CO(1-0) intensity map, serves as an ideal site for investigating this transition. Utilizing the Arizona Radio Observatory Sub-Millimeter Telescope, we obtained mapping observations of CO(2-1), $^{13}$CO(2-1), and CO(3-2) across this linear edge. The intensity ratio between CO(2-1) and $^{13}$CO(2-1) indicates a lower limit of the $^{12}C/^{13}C$ ratio of $54\pm 17$. Based on multi-transition observations of CO and $^{13}$CO, we performed Markov Chain Monte Carlo (MCMC) fit of the physical properties across this edge using non-Local Thermodynamic Equilibrium analysis with the RADEX code, based on the Large velocity Gradient (LVG) assumption. The number density profile exhibits a pronounced jump coinciding with the H$_2$ infrared emission peak. The cold HI gas within the molecular cloud, manifested as HI-Narrow Self-Absorption (HINSA) features, is detected along the cloud edge. Our quantitative comparison with numerical simulations provides tentative evidence that shocks induced by colliding gas flows may contribute to the atomic-to-molecular phase transition observed along the linear edge. |
| title | Physical Properties and HI-to-H2 Transition Across Taurus Linear Edge |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2504.01299 |