Large Redshift Surveys Research Articles

The CNOC2 Field Galaxy Redshipt Survey

Fundamental to our understanding of the universe is the evolution of structures, from galaxies to clusters of galaxies to large-scale sheets and filaments of galaxies and voids. The investigation of the evolution of large-scale structure not only provides us with the key test of theories of structure formation, but also allows us to measure fundamental cosmological parameters. The CNOC2 (Canadian Network for Observational Cosmology) Field Galaxy Redshift Survey is the first large redshift survey of faint galaxies carried out with the explicit goal of investigating the evolution of large scale structure. This survey also provides the largest redshift and photometric data set currently available for the study of galaxy population and evolution at the moderate redshift range between 0.1 and 0.6. In this paper we describe the scope and technique of the survey, its status, and some preliminary results.

Cross‐correlating Cosmic Microwave Background Radiation Fluctuations with Redshift Surveys: Detecting the Signature of Gravitational Lensing

Density inhomogeneities along the line of sight distort fluctuations in the cosmic microwave background. Usually, this effect is thought of as a small second-order effect that mildly alters the statistics of the microwave background fluctuations. We show that there is a first-order effect that is potentially observable if we combine microwave background maps with large redshift surveys. We introduce a new quantity that measures this lensing effect, T(δθ ∇ T), where T is the microwave background temperature and δθ is the lensing due to matter in the region probed by the redshift survey. We show that the expected signal is first order in the gravitational lensing bending angle, (δθ)21/2, and find that it should be easily detectable, signal-to-noise ratio ~ 15-35, if we combine the Microwave Anisotropy Probe satellite and Sloan Digital Sky Survey data. Measurements of this cross-correlation will directly probe the bias factor, i.e., the relationship between fluctuations in mass and fluctuations in galaxy counts.

Determination of the Baryon Density from Large‐Scale Galaxy Redshift Surveys

We estimate the degree to which the baryon density, $\Omega_{b}$, can be determined from the galaxy power spectrum measured from large scale galaxy redshift surveys, and in particular, the Sloan Digital Sky Survey. A high baryon density will cause wiggles to appear in the power spectrum, which should be observable at the current epoch. We assume linear theory on scales $\geq 20h^{-1}Mpc$ and do not include the effects of redshift distortions, evolution, or biasing. With an optimum estimate of $P(k)$ to $k\sim 2\pi/(20 h^{-1} Mpc)$, the $1 \sigma$ uncertainties in $\Omega_{b}$ are roughly 0.07 and 0.016 in flat and open ($\Omega_{0}=0.3$) cosmological models, respectively. This result suggests that it should be possible to test for consistency with big bang nucleosynthesis estimates of $\Omega_{b}$ if we live in an open universe.

Filament and shape statistics: a quantitative comparison of cold + hot

A new class of geometric statistics for analyzing galaxy catalogs is presented. Filament statistics quantify filamentarity and planarity in large scale structure in a manner consistent with catalog visualizations. These statistics are based on sequences of spatial links which follow local high-density structures. From these link sequences we compute the discrete curvature, planarity, and torsion. Filament statistics are applied to CDM and CHDM ($\Omega_\nu = 0.3$) simulations of Klypin \etal (1996), the CfA1-like mock redshift catalogs of Nolthenius, Klypin and Primack (1994, 1996), and the CfA1 catalog. We also apply the moment-based shape statistics developed by Babul \& Starkman (1992), Luo \& Vishniac (1995), and Robinson \& Albrecht (1996) to these same catalogs, and compare their robustness and discriminatory power versus filament statistics. For 100 Mpc periodic simulation boxes ($H_0 = 50$ km s$^{-1}$ Mpc$^{-1}$), we find discrimination of $\sim 4\sigma$ (where $\sigma$ represents resampling errors) between CHDM and CDM for selected filament statistics and shape statistics, including variations in the galaxy identification scheme. Comparing the CfA1 data versus the models does not yield a conclusively favored model; no model is excluded at more than a $\sim 2\sigma$ level for any statistic, not including cosmic variance which could further degrade the discriminatory power. We find that CfA1 discriminates between models poorly mainly due to its sparseness and small number of galaxies, not due to redshift distortion, magnitude limiting, or geometrical effects. We anticipate that the proliferation of large redshift surveys and simulations will enable the statistics presented here to provide robust discrimination between large-scale structure in various cosmological models.

The CNOC Cluster Redshift Survey Catalogs. I. Observational Strategy and Data Reduction Techniques

view Abstract Citations (205) References (30) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The CNOC Cluster Redshift Survey Catalogs. I. Observational Strategy and Data Reduction Techniques Yee, H. K. C. ; Ellingson, E. ; Carlberg, R. G. Abstract We describe in detail the observational and data reduction techniques of a large redshift survey using multiobject spectroscopy designed to obtain ~2600 faint galaxy redshifts in fields of 16 rich clusters of galaxies with redshifts between 0.2 and 0.55. The primary goal of the survey is to establish whether the mass-to-light ratio of clusters rises with distance from the cluster center. To maximize multiplexing capability, we use ~1500 A wide band-limiting filters matched to the major features of spectra of galaxies at the cluster redshifts to allow for multitiering of spectra. Typically 80-110 spectra can be observed using a single slit mask. The area covered for each cluster ranges from about 1.5 h_100_^-1^ Mpc squared to 1.5 h_100_^-1^ Mpc x 6 h_100_^-1^ Mpc. We describe the observing procedure, which involves real-time photometry and computer-based mask design and mask fabrication on site, allowing for the efficient use of telescope time. The spectroscopic data are extracted semiautomatically, and redshift measurement is performed using cross-correlation techniques. A detailed discussion of the determination of the completeness of the final redshift sample as functions of magnitude, color, geometric position, and redshift is also presented. Publication: The Astrophysical Journal Supplement Series Pub Date: February 1996 DOI: 10.1086/192259 Bibcode: 1996ApJS..102..269Y Keywords: GALAXIES: CLUSTERS: GENERAL; GALAXIES: DISTANCES AND REDSHIFTS; INSTRUMENTATION: SPECTROGRAPHS; SURVEYS full text sources ADS | data products NED (16) SIMBAD (15) Related Materials (5) Part 2: 1996ApJS..102..289Y Part 3: 1997ApJS..113....1E Part 4: 1998ApJS..116..211Y Part 5: 1998ApJS..116..231A Part 6: 1998ApJS..116..247E

CLUSTERING AND LARGE-SCALE STRUCTURE WITH THE SLOAN DIGITAL SKY SURVEY

ABSTRACT The Sloan Digital Sky Survey (SDSS) will provide a complete imaging and spectroscopic survey of the high-latitude northern sky. The 2D survey will image the sky in five colors and will contain nearly 5 x 107 galaxies to g ~23m. The spectroscopic survey will obtain spectra of the brightest 106 galaxies, 105 quasars, and 1035 rich clusters of galaxies (to g ~18.3-19.3m, respectively). I summarize some of the science opportunities that will be made possible by this survey for studying the clustering and large-scale structure of the universe. The survey will identify a complete sample of several thousand rich clusters of galaxies, both in 2D and 3D--the largest automated sample yet available. The extensive cluster sample can be used to determine critical clustering properties such as the luminoisty-function, velocity-function, and mass-function of clusters of galaxies (a critical test for cosmological models), detailed cluster dynamics and Omegadyn, the cluster correlation function and its dependence on richness, cluster evolution, superclustering and voids to the largest scales yet observed, the motions of clusters and their large-scale peculiar velocity field, as well as detailed correlations between x-ray and optical properties of clusters, the density-morphology relation, and cluster-quasar associations. The large redshift survey, reaching to a depth of >~600h-1 Mpc, will accurately map the largest scales yet observed, determine the power-spectrum and correlation function on these large scales for different type galaxies, and study the clustering of quasars to high redshifts (z >~ 4). The implications of the survey for cosmological models, the dark matter, and Omega are also discussed.

Fourier analysis of redshift-space distortions and the determination of

The peculiar velocities of galaxies distort the pattern of galaxy clustering in redshift space, making the redshift space power spectrum anisotropic. In the linear regime, the strength of this distortion depends only on the ratio $\beta \equiv f(\Omega)/b \approx \Omega^{0.6}/b$, where $\Omega$ is the cosmological density parameter and $b$ is the bias parameter. We derive a linear theory estimator for $\beta$ based on the harmonic moments of the redshift space power spectrum. Using N-body simulations, we examine the impact of non-linear gravitational clustering on the power spectrum anisotropy and on our $\beta$-estimator. Non-linear effects can be important out to wavelengths $\lambda \sim 50$Mpc/h or larger; in most cases, they lower the quadrupole moment of the power spectrum and thereby depress the estimate of $\beta$ below the true value. With a sufficiently large redshift survey, the scaling of non-linear effects may allow separate determinations of $\Omega$ and $b$. We describe a practical technique for measuring the anisotropy of the power spectrum from galaxy redshift surveys, and we test the technique on mock catalogues drawn from the N-body simulations. Preliminary application of our methods to the 1.2 Jy IRAS galaxy survey yields $\beta_{est} \sim 0.3-0.4 $ at wavelengths $\lambda \sim 30-40$Mpc/h . Non-linear effects remain important at these scales, so this estimate of $\beta$ is probably lower than the true value.

The evolution of large-scale structure in a universe dominated by cold dark matter

view Abstract Citations (3042) References (60) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The evolution of large-scale structure in a universe dominated by cold dark matter Davis, M. ; Efstathiou, G. ; Frenk, C. S. ; White, S. D. M. Abstract The results of numerical simulations of nonlinear gravitational clustering in universes dominated by weakly interacting, 'cold' dark matter are presented. The numerical methods used and the way in which initial conditions were generated are described, and the simulations performed are catalogued. The evolution of the fundamental statistical properties of the models is described and their comparability with observation is discussed. Graphical comparisons of these open models with the observed galaxy distribution in a large redshift survey are made. It is concluded that a model with a cosmological density parameter omega equal to one is quite unacceptable if galaxies trace the mass distribution, and that models with omega of roughly two, while better, still do not provide a fully acceptable match with observation. Finally, a situation in which galaxy formation is suppressed except in sufficiently dense regions is modelled which leads to models which can agree with observation quite well even for omega equal to one. Publication: The Astrophysical Journal Pub Date: May 1985 DOI: 10.1086/163168 Bibcode: 1985ApJ...292..371D Keywords: Computational Astrophysics; Cosmology; Galactic Clusters; Galactic Evolution; Missing Mass (Astrophysics); Weak Interactions (Field Theory); Astronomical Models; Computerized Simulation; Correlation; Many Body Problem; Mass Distribution; Mass To Light Ratios; Matter (Physics); Radial Velocity; Red Shift; Astrophysics full text sources ADS |

Galaxy clustering and the missing mass

The last several years have witnessed the completion of several large-scale red-shift surveys of galaxies, which have greatly increased our knowledge of the large-scale distribution of galaxies, and have shown that the superclustering phenomenon is widespread and accompanied by large holes in space that appear to be quite deficient in galaxies. The extreme lumpiness of our local Universe presents a challenge to all current theories of galaxy and cluster formation. A comparison with existing n -body simulations results in a poor match to the observations, indicating either that the initial conditions are incorrect or that additional input physics must be specified. With the large CfA red-shift survey complete to magnitude 14.5 at high Galactic latitude, it is possible to determine dynamical masses of small groups as well as large clusters, and the data set provides critical parameters for the mass measurement of the entire Local Supercluster. A trend of increasing mass: light ratio with scale size of measurement emerges from these studies, an effect that implies that dissipative processes probably played a major role in the formation of galaxies and clusters. 1

Low mass portion of the galaxy clustering spectrum

To understand the physical processes which controlled the formation of individual galaxies and clusters of galaxies, it is very important to determine the relative numbers of clusters over a wide range of masses. Although this present day clustering spectrum may not perfectly match the primordial spectrum, one hopes that the major features of the latter might be deduced from the observations. For the massive end of the clustering spectrum, the catalogue of Abell1 can be analysed to provide the necessary data2. For the faint end there are many problems, both observational and theoretical. The observational problems arise if attempts are made to specify group or cluster membership when insufficient data are available. These problems can be avoided by using a complete redshift survey. We have previously presented a large redshift survey of galaxies in a 260 deg2 region of the sky in the direction of the rich clusters Coma and A1367. We found eight groups and clouds which lie in the 4.2 × 104 Mpc3 (assuming H0 = 50 km s−1 Mpc−1) between the local supercluster and the Coma/A1367 supercluster. We use this new survey data here to determine the low mass portion of the clustering spectrum.