A molecular line study towards massive extended green object clumps in the southern sky: chemical properties | |
Yu, Naiping1,2; Wang, Jun-Jie1,2 | |
刊名 | Monthly Notices of the Royal Astronomical Society |
2015-08-11 | |
卷号 | 451期号:3页码:2507-2516 |
关键词 | Stars: Formation Ism: Abundances Ism: Clouds Ism: Molecules |
ISSN号 | 0035-8711 |
DOI | 10.1093/mnras/stv1058 |
文献子类 | Article |
英文摘要 | We present a molecular line study towards 31 extended green object (EGO) clumps in the southern sky using data from MALT90 (Millimetre Astronomy Legacy Team 90 GHz). According to previous multiwavelength observations, we divide our sample into two groups: massive young stellar objects (MYSOs) and HII regions. The most detected lines are N2H+ (J = 1 - 0), HCO+ (J = 1 - 0), HNC (J = 1 - 0), HCN (J = 1 - 0), HC3N (J = 10 - 9), (HCO+)-C-13 (J = 1 - 0), C2H (N = 1 - 0) and SiO (J = 2 - 1), indicating that most EGOs are indeed associated with dense clumps and recent outflow activities. The velocity widths of the N2H+ (J = 1 - 0), (HCO+)-C-13 (J = 1 - 0), C2H (N = 1 - 0) and HC3N (J = 10 - 9) lines are comparable to each other in MYSOs. However, in HII regions the velocity widths of the N2H+ (J = 1 - 0) and C2H (N = 1 - 0) lines tend to be narrower than those of (HCO+)-C-13 (J = 1 - 0) and HC3N (J = 10 - 9). Our results seem to support that N2H+ and C2H emissions mainly come from the gas inside quiescent clumps. In addition, we also find that the [N2H+]/[H13CO+] and [C2H]/[(HCO+)-C-13] relative abundance ratios decrease from MYSOs to H II regions. These results suggest depletion of N2H+ and C2H in the late stages of massive-star formation, probably caused by the formation of HII regions inside. N2H+ and C2H might be used as chemical clocks for massive-star formation by comparing with other molecules such as (HCO+)-C-13 and HC3N. |
WOS关键词 | INFRARED-DARK CLOUDS ; STAR-FORMING REGIONS ; HOT CORES ; INITIAL CONDITIONS ; GALACTIC PLANE ; SOURCE CATALOG ; SAMPLE ; C2H ; EXCITATION ; TELESCOPE |
WOS研究方向 | Astronomy & Astrophysics |
项目编号 | 2015CB857100 |
语种 | 英语 |
WOS记录号 | WOS:000360833700019 |
资助机构 | Commonwealth of Australia ; National Key Basic Research Program of China (973 Program) |
内容类型 | 期刊论文 |
源URL | [http://ir.xao.ac.cn/handle/45760611-7/1609] |
专题 | 新疆天文台_110米口径全可动射电望远镜(SmART)_110米大口径全可动射电望远镜关键技术研究(973项目)_课题1:大样本射电天体的观测和前沿问题研究 |
通讯作者 | Yu, Naiping; Wang, Jun-Jie |
作者单位 | 1.National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China 2.NAOC-TU Joint Centre for Astrophysics, Lhasa 850000, China |
推荐引用方式 GB/T 7714 | Yu, Naiping,Wang, Jun-Jie. A molecular line study towards massive extended green object clumps in the southern sky: chemical properties[J]. Monthly Notices of the Royal Astronomical Society,2015,451(3):2507-2516. |
APA | Yu, Naiping,&Wang, Jun-Jie.(2015).A molecular line study towards massive extended green object clumps in the southern sky: chemical properties.Monthly Notices of the Royal Astronomical Society,451(3),2507-2516. |
MLA | Yu, Naiping,et al."A molecular line study towards massive extended green object clumps in the southern sky: chemical properties".Monthly Notices of the Royal Astronomical Society 451.3(2015):2507-2516. |
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