Detections of 2 cm formaldehyde emissions towards Galactic star-forming regions with 6 cm counterpart

被引：7

作者：

Chen, Xi ^{[1
,2
]}

Shen, Zhi-Qiang ^{[1
,2
]}

Li, Xiao-Qiong ^{[1
,3
]}

Yang, Kai ^{[1
,3
]}

Li, Juan ^{[1
,2
]}

Wang, Jun-Zhi ^{[1
,2
]}

Wu, Ya-Jun ^{[1
,2
]}

Zhao, Rong-Bin ^{[1
,2
]}

Wang, Jin-Qing ^{[1
,2
]}

Dong, Jian ^{[1
,2
]}

Jiang, Dong-Rong ^{[1
,2
]}

Li, Bin ^{[1
,2
]}

机构：

[1] Chinese Acad Sci, Shanghai Astron Observ, Shanghai 200030, Peoples R China

[2] Chinese Acad Sci, Key Lab Radio Astron, Nanjing 210008, Jiangsu, Peoples R China

[3] Univ Chinese Acad Sci, 19A Yuquanlu, Beijing 100049, Peoples R China

来源：

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY | 2017年 / 466卷 / 04期

基金：

中国国家自然科学基金;

关键词：

masers; stars: formation; ISM: molecules; radio lines: ISM; VLA OBSERVATIONS; STELLAR OBJECTS; MASER; H2CO; NGC-7538; SEARCH;

D O I：

10.1093/mnras/stx011

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We report the detections of H2CO emission at the 2 cm transition towards Galactic starforming regions with known 6 cm counterpart using the Shanghai Tianma Radio Telescope. One significant detection (in NGC 7538) and two possible detections (in G23.01-0.41 and G29.96-0.02) were made. Comparing with previous observations, we found that there is a time lag of appearance of 2 and 6 cm emissions detected in NGC 7538, contradicting with the prediction of radiative pumping via radio continuum radiation. Combinations of the variability of 6 cm masers in NGC 7538 suggest that collisional pumping via high-velocity shocks could better explain the 6 cm H2CO maser emission. Under this scheme, excitation of the 2 cm maser may require a higher collision energy compared to the 6 cm transition.

引用

页码：4364 / 4369

页数：6

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