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Search for dark baryon in the universe using oxygen emission lines in soft X-ray band

利用软 X 射线带中的氧发射线寻找宇宙中的暗重子

基本信息

批准号：
16340053
负责人：
SUTO Yasushi
金额：
$ 10.19万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16340053/
关键词：
astrophysics X-ray astronomy dark baryon cluster of galaxies soft X-ray spectroscopy gamma-ray burst 酸素輝線銀河間物質軟X線分光観測 DIOS

项目摘要

1) We developed and ran a cosmological hydro-code with our German collaborator, Dr. Klaus Dolag. The code takes account of a variety of physical processes including radiative cooling, star formation, gas heating due to supernovae, chemical evolution.2) Using the above simulation results, we constructed a mock galaxy catalog in the Local Universe, and discussed the detection feasibility of WHIM (warm-hot intergalactic medium) associated with outskirts of nearby galaxy clusters via oxygen emission lines (Yoshikawa et al. 2004).3) We also studied the detection feasibility of absorption lines of WHIM using the background quasars and X-ray after glow of gamma-ray bursts (Kawahara et al. 2006).4) It has been pointed out that the element abundance in WHIM does not obey the ionization equilibrium. We followed the time evolution of the oxygen ionization states using the simulation data, and indeed showed that the ionization equilibrium is not valid in WHIM. We found that the intensity ratio of oxygen lines in different ionization states is a good indicator of the departure from the ionization equilibrium (Yoshikawa and Sasaki 2006).5) We proposed a new empirical analytic model for temperature and density inhomogeneities in intra-cluster medium, and showed that this nice explains the observation data of galaxy cluster A3667 from Chandra X-ray satellite (kawahar et al.2007,2008).

1)我们与德国合作者克劳斯·多拉格博士一起开发并运行了一个宇宙学水文代码。该代码考虑了各种物理过程，包括辐射冷却，星星形成，超新星引起的气体加热，化学演化。2）利用上述模拟结果，我们构建了本地宇宙中的模拟星系目录，探讨了WHIM检测的可行性（温暖-炽热的星系际介质）通过氧发射线与附近星系团的外围有关（Yoshikawa et al.2004）3）我们还研究了利用背景类星体和伽玛暴余辉X射线探测WHIM吸收线的可行性（Kawahara et al. 2006）。4）已经指出WHIM中的元素丰度不服从电离平衡。我们使用模拟数据跟踪了氧电离态的时间演化，并且确实表明了电离平衡在WHIM中是无效的。我们发现不同电离态氧谱线的强度比是偏离电离平衡的一个很好的指标（Yoshikawa and Sasaki 2006）. 5）我们提出了一个新的团簇内介质温度和密度不均匀性的经验分析模型，并表明这很好地解释了Chandra X射线卫星对星系团A3667的观测数据（kawahar et al.2007，2008）。