NH<sub>3</sub> (1,1) hyperfine intensity anomalies in infall sources

doi:10.1051/0004-6361/202450919

	NH₃ (1,1) hyperfine intensity anomalies in infall sources
	Wu, Gang1,2 ; Henkel, Christian1,2 ; Zhou, Dongdong1 ; Wyrowski, Friedrich 2; Menten, Karl M.2; Esimbek, Jarken1
	2024-10-31
Source Publication	ASTRONOMY & ASTROPHYSICS
ISSN	0004-6361
Volume	691 Pages:A111
Contribution Rank	1
Abstract	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.
Keyword	stars: formation ISM: clouds ISM: kinematics and dynamics ISM: molecules
DOI	10.1051/0004-6361/202450919
Indexed By	SCI
Language	英语
WOS Keyword	AMMONIA OBSERVATIONS ; PHYSICAL CONDITIONS ; MASSIVE STARLESS ; ABSORPTION ; OUTFLOW ; MOTIONS ; PROTOSTAR ; SEARCH ; INFLOW ; STARS
Funding Project	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 Research Area	Astronomy & Astrophysics
WOS Subject	Astronomy & Astrophysics
WOS ID	WOS:001346445300007
Publisher	EDP SCIENCES S A
Funding Organization	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
Citation statistics
Document Type	期刊论文
Identifier	http://ir.xao.ac.cn/handle/45760611-7/7130
Collection	射电天文研究室_恒星形成与演化研究团组
Corresponding Author	Wu, Gang
Affiliation	1.Chinese Acad Sci, Xinjiang Astron Observ, 150 Sci 1-St, Urumqi 830011, Xinjiang, Peoples R China 2.Max Planck Inst Radioastron, Hugel 69, D-53121 Bonn, Germany
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	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.

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