arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新，休息一下吧，周末愉快~~
arXiv 0710.1503astro-ph
收藏

模拟高质量恒星形成区AFGL2591的水线辐射

Modeling the water line emission from the high-mass star-forming region AFGL2591

D. R. Poelman, F. F. S. van der Tak

备注：
accpeted for publication in A&A, 12 pages, 7 figures
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

背景：水线的观测是对稠密分子气体的几何、动力学和化学结构的敏感探测。搭载HIFI和PACS的Herschel能够以前所未有的灵敏度和分辨率探测多条水管线的行为。目的：研究高质量恒星形成区特定水跃迁的诊断价值。作为一个测试案例，我们将我们的模型应用到AFGL 2591区域。结果：一般来说，对于具有恒定水丰度的模型，基态线，1_（10）-1_（01）、1_（11）-0_（00）和2_（12）-1_（01）为吸收型，其余为发射型。对于具有水丰度跳跃剖面的模型，这种行为发生了变化，因为跳跃系数为~10-100的线形剖面与恒定丰度模型中的线形相似，而较大的跳跃导致排放剖面。非对称线轮廓与空腔流出模型，并依赖于倾角。带有外流腔的模型更适合于重现SWAS观测到的1_（10）-1_（01）基态跃迁。PACS光谱将通过连续谱和谱线告诉我们这些区域的几何形状。结论：结果表明，水的低水位跃变对出流特征很敏感，代表了外部区域的激发条件。高激发态跃迁对探测内部激发条件的密度和温度分布更为敏感。因此，赫歇尔任务将非常有助于限制AFGL 2591等高质量恒星形成区的物理和化学结构。

英文摘要：

Context: observations of water lines are a sensitive probe of the geometry, dynamics and chemical structure of dense molecular gas. The launch of Herschel with on board HIFI and PACS allow to probe the behaviour of multiple water lines with unprecedented sensitivity and resolution. Aims: we investigate the diagnostic value of specific water transitions in high-mass star-forming regions. As a test case, we apply our models to the AFGL2591 region. Results: in general, for models with a constant water abundance, the ground state lines, i.e., 1_(10)-1_(01), 1_(11)-0_(00), and 2_(12)-1_(01), are predicted in absorption, all the others in emission. This behaviour changes for models with a water abundance jump profile in that the line profiles for jumps by a factor of ~10-100 are similar to the line shapes in the constant abundance models, whereas larger jumps lead to emission profiles. Asymmetric line profiles are found for models with a cavity outflow and depend on the inclination angle. Models with an outflow cavity are favoured to reproduce the SWAS observations of the 1_(10)-1_(01) ground-state transition. PACS spectra will tell us about the geometry of these regions, both through the continuum and through the lines. Conclusions: it is found that the low-lying transitions of water are sensitive to outflow features, and represent the excitation conditions in the outer regions. High-lying transitions are more sensitive to the adopted density and temperature distribution which probe the inner excitation conditions. The Herschel mission will thus be very helpful to constrain the physical and chemical structure of high-mass star-forming regions such as AFGL2591.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

↑