Physical and chemical properties of Red MSX Sources in the southern sky: H II regions

	Physical and chemical properties of Red MSX Sources in the southern sky: H II regions
	Yu, Naiping1,2 ; Wang, Jun-Jie1,2 ; Li, Nan1,2
刊名	MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
	2015-01-21
卷号	446 期号:3 页码:2566-2581
关键词	stars formation-stars massive-ISM abundances-H II regions-ISM molecules
英文摘要	We have studied the physical and chemical properties of 18 southern Red Midcourse Space Experiment Sources (RMSs), using archival data taken from the Atacama Pathfinder Experiment (APEX) Telescope Large Area Survey of the Galaxy, the Australia Telescope Compact Array, and the Millimeter Astronomy Legacy Team Survey at 90 GHz. Most of our sources have simple cometary/unresolved radio emissions at 4.8 and/or 8.6GHz. The large number of Lyman continuum fluxes (N-L) indicates they are probably massive O- or early B-type star formation regions. Archival IRAS infrared data are used to estimate the dust temperature, which is about 30 K of our sources. Then, the H-2 column densities and the volume-averaged H-2, number densities are estimated using the 870 mu m dust emissions. Large-scale infall and ionized accretions may be occurring in G345.4881+00.3148. We also attempt to characterize the chemical properties of these RMSs through molecular line (N2H+ (1-0) and HCO+ (1-0)) observations. Most of the detected N2H+ and HCO+ emissions match well with the dust emission, implying a close link to their chemical evolution in the RMSs. We found that the abundance of N2H+ is one order of magnitude lower than that in other surveys of infrared dark clouds, and a positive correlation between the abundances of N2H+ and HCO+. The fractional abundance of N2H+ with respect to H-2 seems to decrease as a function of N-L,. These observed trends could be interpreted as an indication of enhanced destruction of N2H+, either by CO or through dissociative recombination with electrons produced by central UV photons.
收录类别	SCI
语种	英语
WOS记录号	WOS:000350272300029
内容类型	期刊论文
源URL	[http://ir.bao.ac.cn/handle/114a11/5715]
专题	国家天文台_射电天文研究部
作者单位	1.Chinese Acad Sci, Natl Astron Observ, Beijing 100012, Peoples R China 2.NAOC TU Joint Ctr Astrophys, Lhasa 850000, Peoples R China
推荐引用方式 GB/T 7714	Yu, Naiping,Wang, Jun-Jie,Li, Nan. Physical and chemical properties of Red MSX Sources in the southern sky: H II regions[J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,2015,446(3):2566-2581.
APA	Yu, Naiping,Wang, Jun-Jie,&Li, Nan.(2015).Physical and chemical properties of Red MSX Sources in the southern sky: H II regions.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,446(3),2566-2581.
MLA	Yu, Naiping,et al."Physical and chemical properties of Red MSX Sources in the southern sky: H II regions".MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 446.3(2015):2566-2581.