We present the largest Wiener reconstruction of the cosmic density field made to date. The reconstruction is based on the Sloan Digital Sky Survey data release 6 covering the northern Galactic cap. We use a novel supersampling algorithm to suppress aliasing effects and a Krylov-space inversion method to enable high performance with high resolution. These techniques are implemented in the ARGO computer code. We reconstruct the field over a 500 Mpc cube with Mpc grid-resolution while accounting both for the angular and radial selection functions of the SDSS, and the shot noise giving an effective resolution of the order of ~10 Mpc. In addition, we correct for the redshift distortions in the linear and nonlinear regimes in an approximate way. We show that the commonly used method of inverse weighting the galaxies by the corresponding selection function heads to excess noise in regions where the density of the observed galaxies is small. It is more accurate and conservative to adopt a Bayesian framework in which we model the galaxy selection/detection process to be Poisson-binomial. This results in heavier smoothing in regions of reduced sampling density. Our results show a complex cosmic web structure with huge void regions indicating that the recovered matter distribution is highly non-Gaussian. Filamentary structures are clearly visible on scales up to ~20 Mpc. We also calculate the statistical distribution of density after smoothing the reconstruction with Gaussian kernels of different radii r_S and find good agreement with a log-normal distribution for ~10 Mpc < r_S < ~30 Mpc.
The Size, Shape and Orientation of Cosmological Voids in the Sloan Digital Sky Survey
我们提出了一个详细的描述，我们的空洞发现算法，这是一个由Hoyle和Vogeley（2002）的处方的扩展。我们包括一个讨论的算法的再现性和鲁棒性，以及检测到的空隙的统计意义。我们将我们的空洞发现者应用于斯隆数字巡天（SDSS）的数据发布5（DR5），并确定了232个宇宙学空洞。将创建包含检测到的空隙的最显著属性的空隙目录。我们提出了一个我们确定的宇宙学空洞的大小，形状和方向的分布的统计分析。我们还研究了红移为0.04 < z < 0.16的可能趋势。我们比较我们的结果，从一个相同的分析模拟目录的基础上的LambdaCDM模型，并找到合理的协议。然而，宇宙学空洞的总体方向存在一些统计学上的显著差异，需要通过进一步改进模拟来加以调和。
Four New Observational $H(z)$ Data From Luminous Red Galaxies of Sloan Digital Sky Survey Data Release Seven
采用微分年龄法，利用Sloan数字巡天数据7（SDSS DR 7）中包含红移$0<z<0.4$的17832个亮红星系（LRGs）测量哈勃参数。利用全谱拟合软件UlySS，用单星族（SSP）模型对这些光谱进行了约简，并得到了我们所选样本的最佳年龄信息。随着年龄-红移关系的减小，获得了4个新的观测$H(z)$数据点，它们分别是$H(z)=69.0\pm19.6$ km s $^{-1}$ Mpc $^{-1}$ at $z=0.07$，$H(z)=68.6\pm26.2$ km s $^{-1}$ Mpc $^{-1}$ at $z=0.12$，$H(z)$ = $72.9\pm29.6$ km s $^{-1}$ Mpc $^{-1}$ at $z=0.2$和$H(z)$ = $88.8\pm36.6$ km s $^{-1}$ Mpc $^{-1}$ at $z=0.28$.结合其他21个OHD数据点，给出了平面和非平面$Λ$ CDM模型的约束性能。
The Pittsburgh Sloan Digital Sky Survey MgII Quasar Absorption-Line Survey Catalog
我们提出了一个红移区间为0.36 <= z <= 2.28的镁II类星体吸收线系统的目录。该星表由斯隆数字巡天数据发布4（SDSS DR 4）类星体光谱构建。目前，该目录包含> 17，000个测量的MgII双峰。我们还提供了用于构建目录的~ 44，600个类星体光谱的数据，包括红移和星等信息，连续归一化光谱，以及在我们的置信阈值下可检测到的红移相关最小静止等效宽度的相应阵列。该目录可在网上查阅。仔细的第二次搜索的500个随机光谱表明，每100个光谱搜索，大约一个显着的MgII系统被意外拒绝。目前的计划，扩大目录以外的DR 4类星体进行了讨论。已知许多MgII吸收体与星系有关。因此，结合大尺寸和充分理解的统计数据，使这个目录的理想精密研究的低电离和中性气体区域与星系在低到中等红移。使用该目录的MgII吸收剂的统计分析将在随后的论文中提出。
Direct Minkowski Functional analysis of large redshift surveys: a new high--speed code tested on the luminous red galaxy Sloan Digital Sky Survey-DR7 catalogue
Observational Upper Bound on the Cosmic Abundances of Negative-mass Compact Objects and Ellis Wormholes from the Sloan Digital Sky Survey Quasar Lens Search
