NH3 (1,1) hyperfine intensity anomalies in infall sources
文献类型:期刊论文
作者 | Wu, Gang1,2![]() ![]() ![]() ![]() |
刊名 | ASTRONOMY & ASTROPHYSICS
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出版日期 | 2024-10-31 |
卷号 | 691页码:A111 |
关键词 | stars: formation ISM: clouds ISM: kinematics and dynamics ISM: molecules |
ISSN号 | 0004-6361 |
DOI | 10.1051/0004-6361/202450919 |
产权排序 | 1 |
英文摘要 | Identifying infall motions is crucial for our understanding of accretion processes in regions of star formation. The NH3 (1,1) hyperfine intensity anomaly (HIA) has been proposed to be a readily usable tracer for such infall motions in star-forming regions harboring young stellar objects at very early evolutionary stages. In this paper, we seek to study the HIA toward 15 infall candidate regions in order to assess its reliability as an infall tracer. Using deep observations of the NH3 (1, 1) transition with the Effelsberg 100 m telescope, we identified HIAs toward all 15 targets. Of the 15 sources, 14 exhibit anomalous intensities in either the inner or outer satellite lines. All the derived HIAs conform to the framework of the existing two models, namely hyperfine selective trapping (HST) and systematic contraction or expansion motion (CE) models. In our sample of infall candidates, the majority of the HIAs remain consistent with the HST model. Only in three targets are the HIAs consistent with infall motions under the CE model. Thus, the HIA could indeed be used as an infall tracer, but does not appear to be highly sensitive to infall motions in our single-dish data. Nevertheless, the emission could be blended with emission from outflow activities. HIAs consistent with the HST model show stronger anomalies with increasing kinetic temperatures (TK), which is expected based on the HST model. On the other hand, HIAs consistent with infall motions show little dependence on Tk . Therefore, HIAs may preferably trace the infall of cold gas. |
WOS关键词 | AMMONIA OBSERVATIONS ; PHYSICAL CONDITIONS ; MASSIVE STARLESS ; ABSORPTION ; OUTFLOW ; MOTIONS ; PROTOSTAR ; SEARCH ; INFLOW ; STARS |
资助项目 | National Key R&D Program of China[2022YFA1603103] ; CAS Light of West China Program[2021-XBQNXZ-028] ; National Natural Science foundation of China[12103082] ; National Natural Science foundation of China[11603063] ; National Natural Science foundation of China[12173075] ; Natural Science Foundation of Xinjiang Uygur Autonomous Region[2022D01A362] ; Youth Innovation Promotion Association CAS |
WOS研究方向 | Astronomy & Astrophysics |
语种 | 英语 |
WOS记录号 | WOS:001346445300007 |
出版者 | EDP SCIENCES S A |
资助机构 | National Key R&D Program of China ; CAS Light of West China Program ; National Natural Science foundation of China ; Natural Science Foundation of Xinjiang Uygur Autonomous Region ; Youth Innovation Promotion Association CAS |
源URL | [http://ir.xao.ac.cn/handle/45760611-7/7129] ![]() |
专题 | 恒星形成与演化研究团组 |
通讯作者 | Wu, Gang |
作者单位 | 1.Max Planck Inst Radioastron, Hugel 69, D-53121 Bonn, Germany 2.Chinese Acad Sci, Xinjiang Astron Observ, 150 Sci 1-St, Urumqi 830011, Xinjiang, Peoples R China |
推荐引用方式 GB/T 7714 | Wu, Gang,Henkel, Christian,Zhou, Dongdong,et al. NH3 (1,1) hyperfine intensity anomalies in infall sources[J]. ASTRONOMY & ASTROPHYSICS,2024,691:A111. |
APA | Wu, Gang,Henkel, Christian,Zhou, Dongdong,Wyrowski, Friedrich,Menten, Karl M.,&Esimbek, Jarken.(2024).NH3 (1,1) hyperfine intensity anomalies in infall sources.ASTRONOMY & ASTROPHYSICS,691,A111. |
MLA | Wu, Gang,et al."NH3 (1,1) hyperfine intensity anomalies in infall sources".ASTRONOMY & ASTROPHYSICS 691(2024):A111. |
入库方式: OAI收割
来源:新疆天文台
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