权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Measuring H2 spin temperature in molecular cloud by near-infrared absorption spectroscopy

利用近红外吸收光谱测量分子云中 H2 自旋温度

基本信息

批准号：
323730877
负责人：
Dr. Miwa Goto, Ph.D.
金额：
--
依托单位：
Lehrstuhl für beobachtende und experimentelle Astrophysik
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2016
资助国家：
德国
起止时间：
2015-12-31 至 2019-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/323730877?language=en
关键词：
Measuring H2 spin temperature molecular

项目摘要

We propose to measure the nuclear spin temperature of the molecular hydrogen for the first time in a quiescent cloud. The formation of H2 is the archetype of the surface chemistry in the interstellar medium, and yet our understanding is plagued with weak links and unknowns. The nuclear spin of H2 cools down only very slowly in a molecular cloud. The spin temperature of H2 therefore retains the pristine relic of its formation on a dust grain surface. The high spin temperature of newly formed H2 in a quiescent cloud will be one of the pillars of our understanding how the molecules come to fill the interstellar medium. We will quantitatively constrain the H2 spin temperature by the observation of vibrational transitions of H2 v=1-0 S(0) and S(1) at 2.223 and 2.122 um in absorption against the stars behind the dense and translucent clouds in the Pipe Nebula. Such attempts were beyond the scope of astronomical observations until now, for the lack of decent continuum sources toward quiescent clouds, and for the lack of high-resolution spectrographs at large aperture telescopes with a high observing efficiency. The latter hurdle will be lifted by CRIRES+, which will come to the VLT in 2017 after its major upgrade. To overcome the former, we will make use of the populous late type stars, and apply our newly developed technique to remove the stellar absorption lines to the finest precision. The observing scheme, which we will refine in the program, will also be an important asset to chart the mass of a molecular cloud for the first time with its principal constituent, the molecular hydrogen.

我们首次提出在静止云中测量氢分子的核自旋温度。H2的形成是星际介质中表面化学的原型，然而我们的理解受到薄弱环节和未知因素的困扰。H2的核自旋在分子云中冷却得非常缓慢。因此，H2的自旋温度保留了它在尘埃颗粒表面形成时的原始遗迹。静止云中新形成的H2的高自旋温度将成为我们理解分子如何填充星际介质的支柱之一。我们将通过观测H2 v=1-0 S(0)和S(1)在2.223和2.122 um的振动跃迁来定量地约束H2的自旋温度。在此之前，这种尝试都超出了天文观测的范围，因为没有朝向静止云的像样的连续源，也没有观测效率高的大口径望远镜上的高分辨率摄谱仪。后一个障碍将由CRIRES+解除，CRIRES+将在2017年进行重大升级后进入VLT。为了克服前者，我们将利用人口稠密的晚型恒星，并应用我们新开发的技术以最精确的精度去除恒星吸收线。观测方案，我们将在程序中完善，也将是一个重要的资产，第一次绘制分子云的质量与它的主要成分，氢分子。