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Theoretical study for the fundamental physical processes of the star formation in proto-galactic clouds and the formation of cosmological first luminous objects.

对原银河云中恒星形成和宇宙学第一个发光物体形成的基本物理过程的理论研究。

基本信息

批准号：
14540227
负责人：
NISHI Ryoichi
金额：
$ 2.11万
依托单位：
Niigata University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14540227/
关键词：
galaxy formation star formation primordial gas cosmology

项目摘要

We investigated on the formation process of early cosmological luminous objects and discussed them for the observational corroboration of physical scenarios. Firstly, we studied the star formation process in the primordial gas, and estimate the emission line luminosities of H_2 and HD molecules, which are important because they are expected to characterize the primordial star formation process. For the formation process of the first generation stars, HD is not important. But for the star formation in the massive proto-galactic clouds, HD plays important roles as coolant. LiH molecule never plays important role. Secondly, we studied the evolution of the filamentary clouds, which is formed via the fragmentation process of the proto-galactic clouds and important for the formation of the star forming core. In the collapse and the fragmentation processes, the fraction of the dark matter component is very significant. Considering the filaments formed in the gravitational potential well, it is impossible to collapse enough before fragmentation. Thus, efficient star formation is expected to be impossible. We also estimated the emission line luminosities of H_2 and HD molecules for the filaments without dark matter, which are the mother objects of the star formation cores. Finally, estimating the primordial star formation rate in the proto-galactic clouds, we discuss the observational possibility of the formation process of early cosmological luminous objects. Because of the redshift effects, it is important to observe mid-infrared radiation. Thus, SPICA (Space Infrared Telescope for Cosmology and Astrophysics) has the best chance for the observational corroboration in the next generation facilities. If the star formation rate in the primordial gas is as large as the star forming rate of the usual star burst galaxies, SPICA can observe the primordial molecular lines from the first forming process of early cosmological luminous objects.

我们研究了早期宇宙学发光天体的形成过程，并对它们进行了讨论，以便对物理方案进行观测确证。首先，我们研究了原始气体中星星的形成过程，估算了H_2和HD分子的发射线亮度，这两个分子的发射线亮度对于表征原始星星的形成过程具有重要意义。对于第一代恒星的形成过程，HD并不重要。但对于大质量原星系云中的星星形成，HD起着重要的冷却剂作用。LiH分子从未发挥重要作用。其次，我们研究了由原星系云碎裂而成的、对形成星星形成核有重要作用的物质云的演化。在坍缩和碎裂过程中，暗物质成分的分量是非常重要的。考虑到引力势阱中形成的细丝，在碎裂之前不可能足够坍缩。因此，有效的星星形成预计是不可能的。我们还估算了星星形成核母天体--无暗物质的暗条中H_2和HD分子的发射线光度。最后，通过估算原星系云中的原始星星形成率，讨论了观测早期宇宙学发光天体形成过程的可能性。由于红移效应，对中红外辐射的观测非常重要。因此，SPICA（宇宙学和天体物理学空间红外望远镜）最有可能在下一代设施中进行观测确证。如果原始气体中的星星形成速率与通常的星星爆发星系的星星形成速率一样大，SPICA就可以从早期宇宙学发光天体的第一次形成过程中观测到原始分子线。