The interstellar methanol masers and their environments

CORC > 紫金山天文台 > 中国科学院紫金山天文台 > 分子云与恒星形成研究团组

	The interstellar methanol masers and their environments
	Mao, RQ; Pei, CC ; Zeng, Q
刊名	SCIENCE IN CHINA SERIES G-PHYSICS ASTRONOMY
	2003-04-01
卷号	46 期号:2 页码:137-144
关键词	methanol maser massive star formation interstellar molecular line
ISSN号	1672-1799
英文摘要	To promote the understanding of massive star formation processes, we have studied the 6.6 GHz methanol (CH3OH) masers and their environments-the dense cores and the outer regions of the molecular cloud. The physics of the CH3OH maser or the thermal emission lformation region is studied by fitting the observational data of the 6.6 GHz 5(1)-6(0) A(+) and the 107 GHz 3(1)-4(0) A(+) CH3OH maser emission, using the radiative transfer calculations. The type II characteristics of the 6.6 GHz CH3OH maser are confirmed by the calculation results. A greater intensity of the radiation field leads to an increase in the peak intensity of the maser; however, high densities tend to turn off the maser. The calculation results show that to be a maser the 6.6 GHz CH3OH emission needs a radiation field of 150-300 K and a density not higher than 10(7) cm(3), while the 107 GHz emission requires a radiation field of 210-300 K and a density not higher than 3x10(6)cm(-3). The 6.6 GHz line is maser towards all six studied sources, while the 107 GHz line is maser towards Cep A only. Moreover, the former's intensity is much stronger than the latter. The radiative transfer calculations also indicate that the 6.6 GHz maser emission is so strong that the requirements of its formation (e.g. the radiation field, the density and the kinetic parameters) can only be satisfied at a certain stage of the processes of the massive star formation. Therefore it is often used as one of the most prominent tracers for the massive star formation regions. The calculation results of the simultaneous observations of (1,11) through (4,4) inversion lines of the ammonia (NH3) indicate that both the temperature and the density in the 6.6 GHz CH3OH maser formation regions are higher than that of the NH3 line formation regions. Furthermore, the common fact of IVlsr(CO)I > IVlsr(NH3)I > IVlsr(CH3OH 6.6GHz maser)I in all six sources implies the ongoing developing trends of those gas flows driven by the masers.
学科主题	Physics
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Physics, Multidisciplinary
研究领域[WOS]	Physics
关键词[WOS]	MILLIMETER-WAVE ; DISCOVERY
收录类别	SCI
语种	英语
WOS记录号	WOS:000182042100004
公开日期	2012-08-08
内容类型	期刊论文
源URL	[http://libir.pmo.ac.cn/handle/332002/4582]
专题	紫金山天文台_分子云与恒星形成研究团组
作者单位	1.Chinese Acad Sci, Purple Mt Observ, Nanjing 210008, Peoples R China 2.Chinese Acad Sci, Natl Astron Observ, Beijing 100012, Peoples R China
推荐引用方式 GB/T 7714	Mao, RQ,Pei, CC,Zeng, Q. The interstellar methanol masers and their environments[J]. SCIENCE IN CHINA SERIES G-PHYSICS ASTRONOMY,2003,46(2):137-144.
APA	Mao, RQ,Pei, CC,&Zeng, Q.(2003).The interstellar methanol masers and their environments.SCIENCE IN CHINA SERIES G-PHYSICS ASTRONOMY,46(2),137-144.
MLA	Mao, RQ,et al."The interstellar methanol masers and their environments".SCIENCE IN CHINA SERIES G-PHYSICS ASTRONOMY 46.2(2003):137-144.