Extended ammonia observations towards the integral-shaped filament

doi:10.1051/0004-6361/201630316

	Extended ammonia observations towards the integral-shaped filament
	Wu, Gang 1,2,3,4; Qiu, Keping 2,5; Esimbek, Jarken 1,3; Zheng, Xingwu 2; Henkel, Christian 6,7; Li, Dalei 1; Han, XiaoHong 1
刊名	ASTRONOMY & ASTROPHYSICS
	2018-08-27
卷号	616 页码:12
关键词	ISM: clouds ISM: structure ISM: kinematics and dynamics stars: formation ISM: individual objects: ISF
ISSN号	1432-0746
DOI	10.1051/0004-6361/201630316
通讯作者	Wu, Gang(wug@xao.ac.cn)
英文摘要	Context. Recent observations suggest a scenario in which filamentary structures in the interstellar medium represent the first step towards clumps/cores and eventually star formation. The densest filaments would then fragment into prestellar cores owing to gravitational instability. Aims. We seek to understand the roles filamentary structures play in high-mass star formation. Methods. We mapped the integral-shaped filament (ISF) located at the northern end of the Orion A molecular cloud in NH3 (1, 1) and (2, 2). The observations were made using the 25 m radio telescope operated by the Xinjiang Astronomical Observatory, Chinese Academy of Sciences. The whole filamentary structure, about 1.2 degrees x 0.6 degrees, is uniformly and fully sampled. We investigate the morphology, fragmentation, kinematics, and temperature properties in this region. Results. We find that the morphology revealed by the map of velocity-integrated intensity of the NH3 (1, 1) line is closely associated with the dust ridge revealed by the Herschel Space Observatory. We identify 6 "lumps" related to the well known OMC-1 to 5 and 11 "sub-clumps" within the map. The clumps and sub-clumps are separated not randomly but in roughly equal intervals along the ISF. The average spacing of clumps is 11.30' +/- 1.31' (1.36 +/- 0.16 pc) and the average spacing of sub-clumps is 7.18' +/- 1.19' (0.86 +/- 0.14 pc). These spacings agree well with the predicted values of the thermal (0.86 pc) and turbulent sausage instability (1.43 pc) by adopting a cylindric geometry of the ISF with an inclination of 60 degrees with respect to the line of sight. We also find a velocity gradient of about 0.6 km s(-1) pc(-1) that runs along the ISF which likely arises from an overall rotation of the Orion A molecular cloud. The inferred ratio between rotational and gravitational energy is well below unity. Furthermore, fluctuations are seen in the centroid velocity diagram along the ISF. The OMC-1 to 5 clouds are located close to the local extrema of the fluctuations, which suggests that there exist gas flows associated with these clumps in the ISF. The derived NH3 (1, 1) and (2, 2) rotation temperatures in the OMC-1 are about 30-40 K while lower temperatures (below 20 K) are obtained in the northern and southern parts of the ISF. In OMC-2, OMC-3, and the northern part of OMC-4, we find higher and lower temperatures at the boundaries and in the interior, respectively.
WOS关键词	MASSIVE STAR-FORMATION ; ORION MOLECULAR CLOUD ; INFRARED DARK CLOUD ; DENSE CORES ; INTERSTELLAR AMMONIA ; PHYSICAL CONDITIONS ; FRAGMENTATION ; NH3 ; THERMOMETER ; MONOCEROS
WOS研究方向	Astronomy & Astrophysics
语种	英语
出版者	EDP SCIENCES S A
WOS记录号	WOS:000442743800003
内容类型	期刊论文
源URL	[http://libir.pmo.ac.cn/handle/332002/21463]
专题	中国科学院紫金山天文台
通讯作者	Wu, Gang
作者单位	1.Chinese Acad Sci, Xinjiang Astron Observ, Sci 1 St 150,Beijing Rd, Urumqi, Peoples R China 2.Nanjing Univ, Sch Astron & Space Sci, 163 Xianlin Ave, Nanjing 210023, Jiangsu, Peoples R China 3.Chinese Acad Sci, Key Lab Radio Astron, Urumqi 830011, Peoples R China 4.Univ Chinese Acad Sci, Beijing 100080, Peoples R China 5.Nanjing Univ, Minist Educ, Key Lab Modern Astron & Astrophys, Nanjing 210023, Jiangsu, Peoples R China 6.Max Planck Inst Radioastron, Hugel 69, D-53121 Bonn, Germany 7.King Abdulaziz Univ, Dept Astron, POB 80203, Jeddah 21589, Saudi Arabia
推荐引用方式 GB/T 7714	Wu, Gang,Qiu, Keping,Esimbek, Jarken,et al. Extended ammonia observations towards the integral-shaped filament[J]. ASTRONOMY & ASTROPHYSICS,2018,616:12.
APA	Wu, Gang.,Qiu, Keping.,Esimbek, Jarken.,Zheng, Xingwu.,Henkel, Christian.,...&Han, XiaoHong.(2018).Extended ammonia observations towards the integral-shaped filament.ASTRONOMY & ASTROPHYSICS,616,12.
MLA	Wu, Gang,et al."Extended ammonia observations towards the integral-shaped filament".ASTRONOMY & ASTROPHYSICS 616(2018):12.