Large-scale Spectroscopic Mapping of the rho Ophiuchi Molecular Cloud Complex. I. The C2H-to-N2H+ Ratio as a Signpost of Cloud Characteristics

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	Large-scale Spectroscopic Mapping of the rho Ophiuchi Molecular Cloud Complex. I. The C2H-to-N2H+ Ratio as a Signpost of Cloud Characteristics
	Pan, Zhichen 1; Li, Di 1,2,3; Chang, Qiang4 ; Qian, Lei 1,2; Bergin, Edwin A.5; Wang, Junzhi 6
刊名	ASTROPHYSICAL JOURNAL
	2017-02-20
通讯作者邮箱	panzc@nao.cas.cn ; dili@nao.cas.cn
卷号	836 期号:2 页码:194
关键词	ISM: individual objects (rho Ophiuchi molecular cloud complex) ISM: molecules radio lines: ISM stars: formation
ISSN号	0004-637X
通讯作者	Zhichen Pan
英文摘要	We present 2.5-square-degree C2H N = 1-0 and N2H+ J = 1-0 maps of the rho Ophiuchi molecular cloud complex. These are the first large-scale maps of the rho Ophiuchi molecular cloud complex with these two tracers. The C2H emission is spatially more extended than the N2H+ emission. One faint N2H+ clump, Oph-M, and one C2H ring, OphRingSW, are identified for the first time. The observed C2H-to-N2H+ abundance ratio ([C2H]/[N2H+]) varies between 5 and 110. We modeled the C2H andN(2)H(+) abundances with 1D chemical models, which show a clear decline of [C2H]/ [N2H+] with chemical age. Such an evolutionary trend is little affected by temperatures when they are below 40 K. At high density (n(H) > 10(5) cm(-3)), however, the time it takes for the abundance ratio to drop at least one order of magnitude becomes less than the dynamical time (e.g., turbulence crossing time of similar to 10(5) yr). The observed [C2H]/[N2H+] difference between L1688 and L1689 can be explained by L1688 having chemically younger gas in relatively less dense regions. The observed [C2H]/[N2H+] values are the results of time evolution, accelerated at higher densities. For the relatively low density regions in L1688 where only C2H emission was detected, the gas should be chemically younger.
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Astronomy & Astrophysics
研究领域[WOS]	Astronomy & Astrophysics
关键词[WOS]	STAR-FORMING REGIONS ; INITIAL CONDITIONS ; COLOGNE DATABASE ; MAIN CLOUD ; DARK CLOUD ; MILLIMETER ; CORE ; EMISSION ; LINE ; C2H
收录类别	SCI
语种	英语
WOS记录号	WOS:000395797900010
内容类型	期刊论文
源URL	[http://ir.xao.ac.cn/handle/45760611-7/1432]
专题	天体化学研究团组新疆天文台_射电天文研究室
作者单位	1.Chinese Acad Sci, Natl Astron Observ, A20 Datun Rd, Beijing 100012, Peoples R China 2.Chinese Acad Sci, Key Lab Radio Astron, Nanjing 210008, Jiangsu, Peoples R China 3.Univ Chinese Acad Sci, 19 Yuquan Rd, Beijing, Peoples R China 4.Chinese Acad Sci, Xinjiang Astron Observ, 150 Sci 1 St, Urumqi 830011, Peoples R China 5.Univ Michigan, Dept Astron, 500 Church St, Ann Arbor, MI 48109 USA 6.Chinese Acad Sci, Shanghai Astron Observ, 80 Nandan Rd, Shanghai 200030, Peoples R China
推荐引用方式 GB/T 7714	Pan, Zhichen,Li, Di,Chang, Qiang,et al. Large-scale Spectroscopic Mapping of the rho Ophiuchi Molecular Cloud Complex. I. The C2H-to-N2H+ Ratio as a Signpost of Cloud Characteristics[J]. ASTROPHYSICAL JOURNAL,2017,836(2):194.
APA	Pan, Zhichen,Li, Di,Chang, Qiang,Qian, Lei,Bergin, Edwin A.,&Wang, Junzhi.(2017).Large-scale Spectroscopic Mapping of the rho Ophiuchi Molecular Cloud Complex. I. The C2H-to-N2H+ Ratio as a Signpost of Cloud Characteristics.ASTROPHYSICAL JOURNAL,836(2),194.
MLA	Pan, Zhichen,et al."Large-scale Spectroscopic Mapping of the rho Ophiuchi Molecular Cloud Complex. I. The C2H-to-N2H+ Ratio as a Signpost of Cloud Characteristics".ASTROPHYSICAL JOURNAL 836.2(2017):194.