Large-Scale Clustering of Sloan Digital Sky Survey Quasars: Impact of the Baryon Density and the Cosmological Constant
Large-Scale Clustering of Sloan Digital Sky Survey Quasars: Impact of the Baryon Density and the Cosmological Constant
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DOI：
10.1093/pasj/57.4.529
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发表时间：
2004-12
影响因子：
2.3
通讯作者：
Kazuhiro Yahata;Yasushi Suto;I. Kayo;Takahiko Matsubara;A. Connolly;DanielE. Vanden Berk;Ravi Sheth;I. Szapudi;S. Anderson;N. Bahcall;J. Brinkmann;I. Csabai;Xiaohui Fan;J. Loveday;A. Szalay;Donald G. York
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作者：
Kazuhiro Yahata;Yasushi Suto;I. Kayo;Takahiko Matsubara;A. Connolly;DanielE. Vanden Berk;Ravi Sheth;I. Szapudi;S. Anderson;N. Bahcall;J. Brinkmann;I. Csabai;Xiaohui Fan;J. Loveday;A. Szalay;Donald G. York
我们报告了SDSS类星体聚类分析的第一个结果。我们计算了SDSS类星体在8 h−1 Mpc <s <500 h−1 Mpc时红移空间的两点相关函数（2PCF），并特别注意了它的重子特征。我们的样本包括从SDSS数据发布4中提取的19986个类星体。样品的红移范围为0.72≤z≤2.24（平均红移为z =1）。校正后的i波段视星等范围为15.0≤mi,rc≤19.1。由于类星体样本的数量密度相对较低，在功率谱中由于重子密度（Ωb）而产生的凸起并不清晰可见。然而，重子密度的影响是扭曲2PCF的整体形状。扭曲的程度使它成为重子特征的一个有趣的替代测量。假设一个尺度无关的线性偏差和一个空间平坦的宇宙，我们将观测到的类星体2PCF和预测的物质2PCF结合起来，对Ωb和ΩΛ（宇宙常数）施加约束。我们的结果在2 σ置信水平上拟合为0.80−2.8Ωb < ΩΛ < 0.90−1.4Ωb。我们的类星体样本的“平均”偏差参数为1.59 σ8−1（对于Ωb =0）。04和ΩΛ =0。7)，其中σ8为8 h−1 Mpc时的顶帽质量波动幅度。我们还估计了类星体在z =0,bQSO,Fry(0)处对应的偏置参数，假设Fry的偏置演化模型。对于Ωb =0。04， ΩΛ =0。73， Ωd =0。23、得到bQSO，Fry(0) = 0.54 + 0.83 σ8−1，适用于0.6 <σ 8 < 1.0。
We report on the first result from the clustering analysisof SDSS quasars. We computed the two-point correlation function (2PCF) of SDSS quasars in redshift space at 8 h −1 Mpc <s <500 h −1 Mpc, with particular attention to its baryonic signature. Our sample consisted of 19986 quasars extracted from the SDSS Data Release 4. The redshift range of the sample is 0.72 ≤ z ≤ 2.24 (the mean redshift is z =1 .46) and the reddening-corrected i-band apparent magnitude range is 15.0 ≤ mi,rc ≤ 19.1. Due to the relatively low number density of the quasar sample, the bump in the power spectrum due to the baryon density, Ωb, is not clearly visible. The effect of the baryon density is, however, to distort the overall shape of the 2PCF. The degree of distortion makes it an interesting alternate measure of the baryonic signature. Assuming a scale-independent linear bias and a spatially flat universe, we combined the observed quasar 2PCF and the predicted matter 2PCF to put constraints on Ωb and ΩΛ (the cosmological constant). Our result was fitted as 0.80 −2.8Ωb < ΩΛ < 0.90 −1.4Ωb at the 2 σ confidence level. The “mean” bias parameter of our quasar sample is 1.59 σ8 −1 (for Ωb =0 .04 and ΩΛ =0 .7), where σ8 is the top-hat mass fluctuation amplitude at 8 h −1 Mpc. We also estimated the corresponding bias parameter of quasars at z =0 ,bQSO,Fry(0), assuming Fry’s bias evolution model. For Ωb =0 .04, ΩΛ =0 .73, and Ωd =0 .23, we found bQSO,Fry(0) = 0.54 + 0.83 σ8 −1 which is valid for 0.6 <σ 8 < 1.0.