重构Ly-α线丛的功率谱约束对数正态(LN)模型参数  

Determination of Parameters of Lognormal Model from the Power Spectrum of Reconstruction LyαForest

作　　者：邱旭升[1] 林宣滨[1] 

机构地区：[1]中国科学技术大学天体物理中心,合肥230026

出　　处：《天文学报》2006年第2期119-130,共12页Acta Astronomica Sinica

基　　金：国家重点基础研究专项及教育部优秀青年教师资助计划项目

摘　　要：选择3个类星体Keck观测样本,使用Gauss化方法重构宇宙质量密度扰动场,并计算相应的小波功率谱．同时,设定对数正态(LN)模型中的形状因子Γ和平滑因子r为自由参数,并通过数值模拟生成模拟样本,与观测样本的统计结果做拟合,来确定Γ和r．结合观测的辐射流量功率谱和数值模拟的结果可以唯一确定Γ的值,最后得到Γ≈0．50,r≈0．0g．类星体的辐射流量是非Gauss的,使用传统的Gauss化方法无法消除非Gauss特征．但是观测样本和数值模拟样本的偏斜谱、峰度谱以及尺度-尺度相关等非Gauss特征的表征量在研究的尺度(>100kpc)上表现一致,这就支持了拟合的结果．Three samples of quasar spectra observed by the Keck telescope are selected and reconstructed the perturbations of mass density using the Gaussianization method, from which the wavelet power spectra are obtained. Two parameters in the lognormal model, namely the shape factor Г and the Jeans smoothing factor r, are input as thawed parameters. The most possible values of Г and r are determined by comparing the result of statistical analysis on the observed sample with that on a simulated sample. The result is： Г ≈ 0.50 and r ≈ 0.09. The non-Guassian features contained in the quasar spectra can not be excluded using the traditional Gaussianization method. However, at the scale of 〉 100kpc, these features have little/no influence on our results described above. This argument has been verified by comparing the observed sample with the simulated on their skewness and kurtosis spectra, and the scale-scale correlations.

关 键 词：宇宙:理论 星系际介质 类星体:吸收线 

分 类 号：P142[天文地球—天体物理]