A Study of Large-Scale Structures in the High-Redshift Universe with Spectroscopic Observations of QSO

在观测研究方面，分析了Keck HIRES观测到的类星体三重态系统（KP 76，77，78）的高色散谱。W-e测量了Ly-α森林中Ly-α和金属吸收线的红移（z）、柱密度（N（H）或N（金属））和多普勒参数（B）。在KP 76、77和78中测得的Ly-α线总数分别为153、263和215。其中，金属线系分别与8条、8条和13条Ly-α线伴生。（1）考察了N（H）与z的关系，发现在z=2.08和2.38处存在logN（H）&lt;14的低密度区，其沿视线方向的尺寸为沿着11-17 h·<-1>Mpc。还提出了z=2.50处的低密度区。这些尺寸不能通过基于下述CDM模型的模拟来解释。(2)当logN（H）&gt;14时，单位z数密度（dn/dz）表现出较强的演化趋势，而当logN（H）&gt;14时，单位z数密度（dn/dz）表现出较弱的演化趋势。 ...更多信息 log N（H）=13-14的演化。(3)在所有情况下，Ly-α线与金属线系统的对数N（H）均大于14。(4)探测到B&gt;150 km/s的Ly-α谱线，与理论模拟结果一致。在理论研究方面，我们基于CDM模型的三维宇宙学数值模拟，考虑了星系形成、超新星爆发和星系风的影响，研究了星系际介质中大尺度结构的形成和金属污染的演化。主要结果如下：（1）金属气体的分布极不均匀，沿着星系结构的高密度区分布，在高密度区形成星系。(2)低密度区不存在金属污染。(3)OVI线与Ly-α线一样具有较宽的范围，因此在Ly-α森林中检测OVI线是一个值得尝试的方法。(4)观测到的低密度区域的模拟预测将由未来的研究进行。少

As for the observational study, the high dispersion spectra of the triplet QSO system (KP 76, 77, 78) obtained with Keck HIRES were analyzed. W-e measured values of redshift (z), column density (N (H) or N (metal)), and Doppler parameter (b) of Ly-α and metallic absorption lines in each Ly-α forest using the VPFIT code. The total numbers of measured Ly-α line are 153, 263, and 215 in KP76, 77, and 78, respectively. Among them, metallic line systems associate with 8, 8, and 13 Ly-α lines, respectively. Based on these measurements, we obtained the following main results : (1) Inspecting N (H) vs. z relation, the low-density regions with logN (H)<14 are found to exist at z=2.08 and 2.38, of which size along line of sight are 11-17 h^<-1> Mpc. Also the low-density region at z=2.50 is suggested. These sizes are not explained by the simulations based on CDM model described below. (2) The number density per unit z (dn/dz) shows a trend of strong evolution for log N (H)>14, while that of weak … More evolution for log N (H)=13-14. (3) The Log N (H) of Ly-α lines with metallic line systems is found to be larger than 14 in all cases. (4) The Ly-α lines with b>150 km/s are detected, which is consistent with theoretical simulations. At present we are preparing for the paper of these results.As for theoretical studies, we investigated the formation of large-scale structures and evolution of metal pollution in intergalactic medium based on the 3-dimensional cosmological numerical simulations for CDM models, which are calculated by taking account of effects of galaxy formation, supernova explosion, and galactic wind. The main results are : (1) The distribution of metallic gas is found to be very inhomogeneous and exist along the high-density regions of filamentary structure, in which galaxy is formed. (2) The metallic pollution does not occur in low-density regions. (3) O VI lines show a broad feature like Ly-α lines, so it is worth trying to detect O VI lines in Ly-α forest. (4) The simulation prediction of the observed low-density regions will be made by a future study. Less