Flux-limited and volume-limited galaxy samples are constructed from SDSS data releases DR4, DR6 and DR7 for statistical analysis. The two-point correlation functions $ξ(s)$, monopole of three-point correlation functions $ζ_0$, projected two-point correlation function $w_p$ and pairwise velocity dispersion $σ_{12}$ are measured to test if galaxy samples are fair for these statistics. We find that with increment of sky coverage of SDSS, $ξ(s)$ of flux-limited sample is extremely robust and insensitive to local structures at low redshift. But for volume-limited samples fainter than $L^*$ at large scales $s>\sim 10\hmpc$, deviation of $ξ(s)$ and $ζ_0$ of DR7 to those of DR4 and DR6 increases with larger absolute magnitude. In the weakly nonlinear regime, there is no agreement between $ζ_0$ of different data releases in all luminosity bins. Furthermore, $w_p$ of volume-limited samples of DR7 in luminosity bins fainter than $-M_{r,0.1}=[18.5,19.5]$ are significantly larger, and $σ_{12}$ of the two faintest volume-limited samples of DR7 display very different scale dependence than results of DR4 and DR6. Our findings call for cautions in understanding clustering analysis results of SDSS faint galaxy samples, and higher order statistics of SDSS volume-limited samples in the weakly nonlinear regime. The first zero-crossing points of $ξ(s)$ of volume-limited samples are also investigated and discussed.
Galaxy-Galaxy Weak Lensing Measurements from SDSS: I. Image Processing and Lensing signals
作为斯隆数字巡天数据发布7(SDSS DR 7)的星系-星系透镜研究系列中的第一篇论文,我们提出了我们的图像处理流水线,该流水线校正了主要由点扩散函数(PSF)引入的系统学。利用该流水线对SDSS DR 7成像数据进行了$r$波段的处理,生成了包含各星系形状信息的背景星系表。基于我们自己的形状测量的星系图像从SDSS DR 7,我们提取的星系星系(GG)透镜信号周围的前景分光星系在不同的光度和恒星质量。总体信号与SDSS DR 4中\citet{Mandelbaum2005, Mandelbaum2006}获得的信号一致。本文的结果具有较高的信噪比,这是由于比SDSS DR 4更大的调查区域,证实了更多的发光/质量星系具有更强的GG透镜信号。我们还将前景星系分为红/蓝和恒星形成/淬火子样本,并分别测量了它们的GG透镜信号。我们发现,在一个特定的恒星质量/光度,红色/淬火星系有相对较强的GG透镜信号比他们的同行,特别是在大半径。这些GG透镜信号可以用来探测星系晕质量关系及其在晕占据或条件光度函数框架中的环境依赖性。
We analyze a set of volume limited sample of galaxies from the SDSS to study the issue of cosmic homogeneity. We use the Renyi entropy of different order to probe the inhomogeneties present in the galaxy distributions. We also calculate the Renyi diveregence to quantify the deviations of the galaxy distribution from a homogeneous Poisson distribution on different length scales. We separately carry out the analysis using the overlapping spheres and the independent voxels. Our analysis suggests that the scale of homogeneity is underestimated in the smaller galaxy samples due to the suppression o…
As a large-scale overdensity collapses, it affects the orientation and shape of galaxies that form, by exerting tidal shear along their axes. Therefore, the shapes of elliptical galaxies align with the tidal field of cosmic structures. This intrinsic alignment provides insights into galaxy formation and the primordial universe, complements late-time cosmological probes and constitutes a significant systematic effect for weak gravitational lensing observations. In the present study, we provide constraints on the linear alignment model using a fully Bayesian field-level approach, using galaxy sh…
Galaxy-galaxy weak-lensing measurement from SDSS: II. host halo properties of galaxy groups
作为使用斯隆数字巡天数据发布7(SDSS DR 7)研究星系星系透镜信号的系列文章的第二篇,我们提出了我们对星系群周围透镜信号的测量和建模。我们将这些星系群分成4个晕质量仓,并测量了4个不同晕中心示踪物周围的信号:最亮中心星系(BCG)、亮度加权中心、数量加权中心和X射线峰值位置。对于X射线和SDSS DR 7交叉识别的组,我们进一步将组分为低和高X射线发射子样品,这两个子样品都分配有两个晕中心示踪剂,BCG和X射线峰位置。星系-星系透镜信号表明,在四个候选星系中,BCGs是最好的晕心示踪剂。我们使用四个贡献的组合模型的透镜信号:偏心NFW主机晕配置文件,子晕的贡献,恒星的贡献,并预计2晕术语。我们对5个参数的后验进行采样,即,通过MCMC软件包使用星系-星系透镜信号计算晕质量、浓度、偏心距离、次晕质量和次晕分数。在考虑到采样效应(例如爱丁顿偏差)后,我们发现从透镜信号获得的最佳拟合晕质量与基于丰度匹配方法在群目录中获得的质量非常一致,除了最低质量仓。主题词:(宇宙学:)引力透镜,星系:星系团:一般
Comments on arXiv:1310.5067: "A response to `A self-consistent public catalogue of voids and superclusters in the SDSS Data Release 7 galaxy surveys' "
We investigate the level of galaxy assembly bias in the Sloan Digital Sky Survey (SDSS) main galaxy sample using ELUCID, a state-of-the-art constrained simulation that accurately reconstructed the initial density perturbations within the SDSS volume. On top of the ELUCID haloes, we develop an extended HOD model that includes the assembly bias of central and satellite galaxies, parameterized as $\mathcal{Q}_\mathrm{cen}$ and $\mathcal{Q}_\mathrm{sat}$, respectively, to predict a suite of one- and two-point observables. In particular, our fiducial constraint employs the probability distribution …
Constraint on the cosmological f(R) model from the multipole power spectrum of the SDSS luminous red galaxy sample and prospects for a future redshift survey
A response to arXiv:1310.2791: A self-consistent public catalogue of voids and superclusters in the SDSS Data Release 7 galaxy surveys
最近,Nadathur和Hotchkiss(2013)提交了一篇论文,讨论了一个新的宇宙空洞目录。本文包括Sutter et al.(2012)中描述的关于空目录的声明。在本说明中,我们回应了这些说法,澄清了Sutter等人(2012)的文本与最新版本的目录之间的一些差异,并对我们的目录与Nadathur & Hotchkiss(2013)的目录之间的差异提供了一些评论。我们目录的所有更新和文档都可以在http://www.cosmicvoids.net上找到。
2MASS/SDSS Close Major-Merger Galaxy Pairs: Luminosity Functions and Merger Mass Dependence
我们选择了一个密切的“主要合并候选人”的星系对样本,以计算的K_{s}光度函数(LF)和对分数的合并/相互作用的组成部分,在本地宇宙中的星系演化。对样本(投影间隔5 h $^{-1}$ kpc $\leq$ r $\leq$ 20 h $^{-1}$ kpc,$K_{s}$ -带星等差$Δ$ $K_{s}$ $\leq$ 1等)是通过结合2微米全天巡天(2 MASS)和斯隆数字巡天(SDSS)数据发布5(DR 5)选择的。由此产生的数据集包含340个星系,覆盖5800平方米。度一个恒星质量函数也是从LF转换而来的。微分对分数显示了星系对的比例几乎是恒定的,作为星系质量的函数,从10 $^{9}$到10 $^{11.5}$ M $_{\sun}$。由于测量的限制,差分对分数比标准的总对分数更少受到绝对幅度偏差的影响。这些结果表明,在0 $<$ z $<$ 0.1宇宙中的主要合并候选对是从$\sim$ 1.6%的星系人口发展而来的,而不依赖于星系质量的对组件低于10 $^{11}$ M $_{\sun}$。合并模型的时间尺度结合LF推导出当地合并率每单位体积的质量大于10 $^{11}$ M $_{\sun}$减少。
Multiple previous studies using several different probes have shown considerable evidence for the existence of cosmological-scale anisotropy and a Hubble-scale axis. One of the probes that show such evidence is the distribution of the directions toward which galaxies spin. The advantage of the analysis of the distribution of galaxy spin directions compared to the CMB anisotropy is that the ratio of galaxy spin directions is a relative measurement, and therefore less sensitive to background contamination such as Milky Way obstruction. Another advantage is that many spiral galaxies have spectra,…
The CASSOWARY spectroscopy survey: A new sample of gravitationally lensed galaxies in SDSS
明亮的引力透镜星系为我们提供了高红移星系的最详细的图像。然而,由于极少数的超亮z~2透镜系统已证实的红移,大多数详细的光谱研究已被限制在他们的范围。为了增加可用于详细跟踪的明亮透镜星系的数量,我们在斯隆数字巡天(SDSS)中开展了一项光谱活动,目标是宽分离(>3角秒)星系-星系透镜候选者。在我们CASSOWARY调查的早期努力的基础上,我们针对SDSS中的候选星系-星系透镜系统的大样本,使用完善的搜索算法识别位于明亮的红色星系周围的蓝色弧状结构。在本文中,我们提出了一个新的红移目录包含25个透镜源SDSS通过光谱的候选星系星系透镜系统的后续确认。在这个新的样本中包括两个已知的z~2最亮的星系(r=19.6和19.7),一个z=1.43的低金属丰度(12 + log(O/H)~8.0)的极端星云线发射星系,以及许多可能进行详细跟踪的系统。源红移跨度为0.9<z<2.5(中位红移为1.9),它们的光学星等范围为19.6<r <22.3. We present a brief source-by-source discussion of the spectroscopic properties extracted from our confirmatory spectra and discuss some initial science results. With mo…
We present the data release of the Uchuu-SDSS galaxies: a set of 32 high-fidelity galaxy lightcones constructed from the large Uchuu 2.1 trillion particle $N$-body simulation using Planck cosmology. We adopt subhalo abundance matching to populate the Uchuu-box halo catalogues with SDSS galaxy luminosities. These cubic box galaxy catalogues generated at several redshifts are combined to create the set of lightcones with redshift-evolving galaxy properties. The Uchuu-SDSS galaxy lightcones are built to reproduce the footprint and statistical properties of the SDSS main galaxy survey, along with …
Three-Dimensional Filamentation Analysis of SDSS DR5 Survey
本文介绍了一种新的方法来计算SDSS DR 5星系团的多尺度三维投影,并将其应用于N体模拟。我们在度量空间中比较了观测样本与模拟样本在8 Mpc至30 Mpc尺度上的一致性。模拟样本比随机样本更接近观察样本,并且其中一个模拟样本比另一个模拟样本表现得更好。我们还发现,所观察到的样品有一个大的平行度值在10 Mpc的规模,这是没有发现从模拟样品或随机样品。关键词:定向,度量空间,星系团,SDSS DR 5。
This work presents the application of a new tool, Obiwan , which uses image simulations to determine the selection function of a galaxy redshift survey and calculate 3-dimensional (3D) clustering statistics. This is a forward model of the process by which images of the night sky are transformed into a 3D large--scale structure catalog. The photometric pipeline automatically detects and models galaxies and then generates a catalog of such galaxies with detailed information for each one of them, including their location, redshift and so on. Systematic biases in the imaging data are therefore imp…
We present 2000 mock galaxy catalogs for the analysis of baryon acoustic oscillations in the Emission Line Galaxy (ELG) sample of the Extended Baryon Oscillation Spectroscopic Survey Data Release 16 (eBOSS DR16). Each mock catalog has a number density of $6.7 \times 10^{-4} h^3 \rm Mpc^{-3}$, covering a redshift range from 0.6 to 1.1. The mocks are calibrated to small-scale eBOSS ELG clustering measurements at scales of around 10 $h^{-1}$Mpc. The mock catalogs are generated using a combination of GaLAxy Mocks (GLAM) simulations and the Quick Particle-Mesh (QPM) method. GLAM simulations are use…
Multiple observations made by several different telescopes have shown asymmetry between the number of spiral galaxies rotating in opposite directions in different parts of the sky. One of the immediate questions regarding the possible asymmetry of the spin directions is whether the distribution forms a cosmological-scale axis. This paper analyzes and compares 10 different datasets published in the past decade, collected by SDSS, Pan-STARRS, and Hubble Space Telescope. The datasets contain spiral galaxies separated by their spin direction, and the distribution can show dipole axes. The analysis…