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Calculating the Excitation Temperature for H2CO Absorption Lines in Molecular Clouds | |
Bu, Jia1,2![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() | |
2024-07-01 | |
Source Publication | RESEARCH IN ASTRONOMY AND ASTROPHYSICS
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ISSN | 1674-4527 |
Volume | 24Issue:7Pages:075022 |
Contribution Rank | 1 |
Abstract | The excitation temperature T-ex for molecular emission and absorption lines is an essential parameter for interpreting the molecular environment. This temperature can be obtained by observing multiple molecular transitions or hyperfine structures of a single transition, but it remains unknown for a single transition without hyperfine structure lines. Earlier H2CO absorption experiments for a single transition without hyperfine structures adopted a constant value of T-ex, which is not correct for molecular regions with active star formation and H ii regions. For H2CO, two equations with two unknowns may be used to determine the excitation temperature T-ex and the optical depth tau, if other parameters can be determined from measurements. Published observational data of the 4.83 GHz (lambda = 6 cm) H2CO (1(10)-1(11)) absorption line for three star formation regions, W40, M17 and DR17, have been used to verify this method. The distributions of T-ex in these sources are in good agreement with the contours of the H110 alpha emission of the H ii regions in M17 and DR17 and with the H2CO (1(10)-1(11)) absorption in W40. The distributions of T-ex in the three sources indicate that there can be significant variation in the excitation temperature across star formation and H ii regions and that the use of a fixed (low) value results in misinterpretation. |
Keyword | ISM: molecules (ISM:) HII regions ISM: clouds |
DOI | 10.1088/1674-4527/ad5b36 |
Indexed By | SCI |
Language | 英语 |
WOS Keyword | GALACTIC PLANE |
Funding Project | National Key R&D Program of China[2022YFA1603103] ; Regional Collaborative Innovation Project of Xinjiang Uyghur Autonomous Region[2022E01050] ; Tianshan Talent Program of Xinjiang Uygur Autonomous Region[2022TSYCLJ0005] ; Natural Science Foundation of Xinjiang Uygur Autonomous Region[2022D01E06] ; Chinese Academy of Sciences (CAS) Light of West China Program[xbzg-zdsys-202212] ; Chinese Academy of Sciences (CAS) Light of West China Program[2020-XBQNXZ-017] ; Chinese Academy of Sciences (CAS) Light of West China Program[2021- XBQNXZ-028] ; National Natural Science Foundation of China (NSFC)[12173075] ; National Natural Science Foundation of China (NSFC)[11973076] ; National Natural Science Foundation of China (NSFC)[12103082] ; Xinjiang Key Laboratory of Radio Astrophysics[2022D04033] ; Youth Innovation Promotion Association CAS ; Chinese Academy of Sciences Presidents International Fellowship Initiative[2022VMA0019] ; Chinese Academy of Sciences Presidents International Fellowship Initiative[2023VMA0030] ; Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan[AP13067768] ; Operation, Maintenance, and Upgrading Fund for Astronomical Telescopes and Facility Instruments, from the Ministry of Finance of China |
WOS Research Area | Astronomy & Astrophysics |
WOS Subject | Astronomy & Astrophysics |
WOS ID | WOS:001269747800001 |
Publisher | NATL ASTRONOMICAL OBSERVATORIES, CHIN ACAD SCIENCES |
Funding Organization | National Key R&D Program of China ; Regional Collaborative Innovation Project of Xinjiang Uyghur Autonomous Region ; Tianshan Talent Program of Xinjiang Uygur Autonomous Region ; Natural Science Foundation of Xinjiang Uygur Autonomous Region ; Chinese Academy of Sciences (CAS) Light of West China Program ; National Natural Science Foundation of China (NSFC) ; Xinjiang Key Laboratory of Radio Astrophysics ; Youth Innovation Promotion Association CAS ; Chinese Academy of Sciences Presidents International Fellowship Initiative ; Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan ; Operation, Maintenance, and Upgrading Fund for Astronomical Telescopes and Facility Instruments, from the Ministry of Finance of China |
Citation statistics | |
Document Type | 期刊论文 |
Identifier | http://ir.xao.ac.cn/handle/45760611-7/6862 |
Collection | 射电天文研究室_恒星形成与演化研究团组 射电天文研究室 |
Corresponding Author | Bu, Jia; Esimbek, Jarken; Zhou, Jianjun |
Affiliation | 1.Chinese Acad Sci, Xinjiang Astron Observ, Urumqi 830011, Peoples R China 2.Univ Chinese Acad Sci, Beijing 100080, Peoples R China 3.Chinese Acad Sci, Key Lab Radio Astron, Urumqi 830011, Peoples R China 4.Xinjiang Key Lab Radio Astrophys, Urumqi 830011, Peoples R China 5.Nazarbayev Univ, Energet Cosmos Lab, Astana 010000, Kazakhstan 6.Al Farabi Kazakh Natl Univ, Inst Expt & Theoret Phys, Alma Ata 050040, Kazakhstan |
First Author Affilication | Xinjiang Astronomical Observatory, Chinese Academy of Sciences |
Corresponding Author Affilication | Xinjiang Astronomical Observatory, Chinese Academy of Sciences |
Recommended Citation GB/T 7714 | Bu, Jia,Esimbek, Jarken,Zhou, Jianjun,et al. Calculating the Excitation Temperature for H2CO Absorption Lines in Molecular Clouds[J]. RESEARCH IN ASTRONOMY AND ASTROPHYSICS,2024,24(7):075022. |
APA | Bu, Jia.,Esimbek, Jarken.,Zhou, Jianjun.,Komesh, Toktarkhan.,Tang, Xindi.,...&Sailanbek, Serikbek.(2024).Calculating the Excitation Temperature for H2CO Absorption Lines in Molecular Clouds.RESEARCH IN ASTRONOMY AND ASTROPHYSICS,24(7),075022. |
MLA | Bu, Jia,et al."Calculating the Excitation Temperature for H2CO Absorption Lines in Molecular Clouds".RESEARCH IN ASTRONOMY AND ASTROPHYSICS 24.7(2024):075022. |
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