Molecular clouds at the edge of the Galaxy I. Variation in the CO J=2-1/1-0 line ratio
文献类型：期刊论文
| 作者 | Luo, C. S.6,7; Tang, X. D.4,5,6,7; Henkel, C.3,7; Menten, K. M.3; Sun, Y.2; Gong, Y.2,3; Zheng, X. W.1; Li, D. L.4,6,7; He, Y. X.4,6,7; Lu, X.11 |
| 刊名 | ASTRONOMY & ASTROPHYSICS
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| 出版日期 | 2025-06-03 |
| 卷号 | 698页码:A54 |
| 关键词 | stars: formation ISM: clouds ISM: molecules |
| ISSN号 | 0004-6361 |
| DOI | 10.1051/0004-6361/202453007 |
| 产权排序 | 1 |
| 英文摘要 | The Galactic edge, at Galactocentric distances of 14-22 kpc, provides an ideal laboratory for studying molecular clouds in an environ-ment that is different from the solar neighborhood, due to its lower gas density, lower metallicity, and little or no perturbation from the spiral arms. Observations of CO(J = 2-1) spectral lines were carried out toward 72 molecular clouds located at the Galactic edge using the IRAM 30 m telescope. With these observations combined with CO(J = 1-0) data from the MWISP project, we investigated the variations in R-21 across these Galactic edge clouds, with R-21 representing CO(2-1)/CO(1-0) integrated intensity ratios. They are found to range from 0.3 to 3.0 with a mean of 1.0 +/- 0.1 in the Galactic edge clouds. The proportions of very low-ratio gas (R-21 < 0.4), low-ratio gas (0.4 <= R-21 < 0.7), high-ratio gas (HRG; 0.7 <= R-21 < 1.0), and very high-ratio gas (VHRG; R-21 >= 1.0) are 6.9%, 29.2%, 26.4%, and 37.5%, respectively, indicating a significant presence of high R-21 ratio molecular gas within these regions. In our Galaxy, the gradient of the R-21 ratio exhibits an initial radial decline followed by a high dispersion with increasing Galactocentric distance and a prevalence for VHRG. There is no apparent systematic variation within the Galactocentric distance range of 14 to 22 kpc. A substantial proportion of HRG and VHRG is found to be associated with compact clouds and regions of star-forming activity, suggesting that the high R-21 ratios stem from dense gas concentrations and recent episodes of star formation. |
| WOS关键词 | EXTREME OUTER GALAXY ; STAR-FORMING REGIONS ; PLANE SURVEY I. ; TO-GAS RATIO ; MILKY-WAY ; PHYSICAL CONDITIONS ; SOLAR CIRCLE ; IRAS SOURCES ; J=2-1/J=1-0 RATIO ; CARBON-MONOXIDE |
| 资助项目 | National Key R&D Program of China[2023YF11608000] ; Tianshan Talent Training Program of Xinjiang Uygur Autonomous Region[2022TSYCLJ0005] ; Chinese Academy of Sciences (CAS) Light of West China Program[xbzg-zdsys-202212] ; Natural Science Foundation of Xinjiang Uygur Autonomous Region[2022D01A359] ; Tianshan Talent Training Program (Chuang Xin Tuan Dui) of Xinjiang Uygur Autonomous Region ; Regional Collaborative Innovation Project of XinJiang Uyghur Autonomous Region[2022E01050] ; National Natural Science Foundation of China[12173075] ; National Natural Science Foundation of China[12373029] ; National Natural Science Foundation of China[12463006] ; Xinjiang Key Laboratory of Radio Astrophysics[2023D04033] ; Youth Innovation Promotion Association CAS ; Chinese Academy of Sciences President's International Fellowship Initiative[2025PVA0048] ; Tianchi Talent Program of Xinjiang Uygur Autonomous Region ; CAS Key Research Program of Frontier Sciences[QYZDJ-SSW-SLH047] ; NASA |
| WOS研究方向 | Astronomy & Astrophysics |
| 语种 | 英语 |
| WOS记录号 | WOS:001507594300033 |
| 出版者 | EDP SCIENCES S A |
| 资助机构 | National Key R&D Program of China ; Tianshan Talent Training Program of Xinjiang Uygur Autonomous Region ; Chinese Academy of Sciences (CAS) Light of West China Program ; Natural Science Foundation of Xinjiang Uygur Autonomous Region ; Tianshan Talent Training Program (Chuang Xin Tuan Dui) of Xinjiang Uygur Autonomous Region ; Regional Collaborative Innovation Project of XinJiang Uyghur Autonomous Region ; National Natural Science Foundation of China ; Xinjiang Key Laboratory of Radio Astrophysics ; Youth Innovation Promotion Association CAS ; Chinese Academy of Sciences President's International Fellowship Initiative ; Tianchi Talent Program of Xinjiang Uygur Autonomous Region ; CAS Key Research Program of Frontier Sciences ; NASA |
| 源URL | [http://ir.xao.ac.cn/handle/45760611-7/7855]  |
| 专题 | 恒星形成与演化研究团组 |
| 通讯作者 | Tang, X. D. |
| 作者单位 | 1.Nanjing Univ, Sch Astron & Space Sci, Nanjing 210093, Peoples R China 2.Chinese Acad Sci, Purple Mt Observ, Nanjing 210008, Peoples R China 3.Max Planck Inst Radioastron, Hugel 69, D-53121 Bonn, Germany 4.Xinjiang Key Lab Radio Astrophys, Urumqi 830011, Peoples R China 5.Chinese Acad Sci, Key Lab Radio Astron & Technol, A20 Datun Rd,Chaoyang Dist, Beijing 100101, Peoples R China 6.Univ Chinese Acad Sci, Beijing 100080, Peoples R China 7.Chinese Acad Sci, Xinjiang Astron Observ, Urumqi 830011, Peoples R China 8.Jinggangshan Univ, Sch Math & Phys, Jian 343009, Peoples R China 9.Chinese Acad Sci, Natl Astron Observ, Beijing 100101, Peoples R China 10.Peking Univ, Kavli Inst Astron & Astrophys, Beijing 100871, Peoples R China |
| 推荐引用方式 GB/T 7714 | Luo, C. S.,Tang, X. D.,Henkel, C.,et al. Molecular clouds at the edge of the Galaxy I. Variation in the CO J=2-1/1-0 line ratio[J]. ASTRONOMY & ASTROPHYSICS,2025,698:A54. |
| APA | Luo, C. S..,Tang, X. D..,Henkel, C..,Menten, K. M..,Sun, Y..,...&Liu, L. D..(2025).Molecular clouds at the edge of the Galaxy I. Variation in the CO J=2-1/1-0 line ratio.ASTRONOMY & ASTROPHYSICS,698,A54. |
| MLA | Luo, C. S.,et al."Molecular clouds at the edge of the Galaxy I. Variation in the CO J=2-1/1-0 line ratio".ASTRONOMY & ASTROPHYSICS 698(2025):A54. |
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