Optical Redshift Surveys

Redshift surveys of galaxies have been over the past decade the major source of information for studies of the large-scale structure of the Universe. Following the completion of the original CfA Redshift Survey, several groups have joined the endeavor, probing different regions of the sky to different depths in a remarkable long-term effort to study the nature of the galaxy distribution and its statistical properties at different scales. Here I summarize the current status of the ongoing surveys drawn from optical galaxy catalogs. The review is not intended to be complete but rather to demonstrate the vitality of the area and to point out that exciting new data should be forthcoming in the next few years.

Characterising filaments in the SDSS volume from the galaxy distribution

Astronomy and Astrophysics ◽

10.1051/0004-6361/202037647 ◽

2020 ◽

Vol 642 ◽

pp. A19 ◽

Cited By ~ 2

Author(s):

Nicola Malavasi ◽

Nabila Aghanim ◽

Marian Douspis ◽

Hideki Tanimura ◽

Victor Bonjean

Keyword(s):

Large Scale ◽

Sloan Digital Sky Survey ◽

Specific Method ◽

Redshift Surveys ◽

Galaxy Distribution ◽

Systematic Uncertainties ◽

Sky Survey ◽

The Galaxy ◽

Free Parameters ◽

Detecting the large-scale structure of the Universe based on the galaxy distribution and characterising its components is of fundamental importance in astrophysics but is also a difficult task to achieve. Wide-area spectroscopic redshift surveys are required to accurately measure galaxy positions in space that also need to cover large areas of the sky. It is also difficult to create algorithms that can extract cosmic web structures (e.g. filaments). Moreover, these detections will be affected by systematic uncertainties that stem from the characteristics of the survey used (e.g. its completeness and coverage) and from the unique properties of the specific method adopted to detect the cosmic web (i.e. the assumptions it relies on and the free parameters it may employ). For these reasons, the creation of new catalogues of cosmic web features on wide sky areas is important, as this allows users to have at their disposal a well-understood sample of structures whose systematic uncertainties have been thoroughly investigated. In this paper we present the filament catalogues created using the discrete persistent structure extractor tool in the Sloan Digital Sky Survey (SDSS), and we fully characterise them in terms of their dependence on the choice of parameters pertaining to the algorithm, and with respect to several systematic issues that may arise in the skeleton as a result of the properties of the galaxy distribution (such as Finger-of-God redshift distortions and defects of the density field that are due to the boundaries of the survey).

Mapping the Large-Scale Structure

10.1017/s0074180900048348 ◽

1994 ◽

Vol 161 ◽

pp. 669-686

Author(s):

V. de Lapparent

Keyword(s):

Large Scale ◽

Background Radiation ◽

Theoretical Models ◽

Large Scale Structure ◽

Scale Structure ◽

Nearby Galaxy ◽

Redshift Surveys ◽

Galaxy Distribution ◽

The Galaxy ◽

Microwave Background Radiation

The nearby galaxy distribution suggests a remarkable structure in which large voids are delineated by dense walls of galaxies in a cell-like pattern. The nearby voids range in diameter from ∼ 10 to ∼ 50h− 1 Mpc. Deeper surveys appear to be consistent with the nearby distribution and show no evidence of voids larger than ∼ 100h −1 ∗ Mpc. We might thus have reached the scale where the universe becomes homogeneous. The size of the largest inhomogeneities in the galaxy distribution is an important issue because it can put tight constraints on the theoretical models when confronted by the high degree of isotropy of the microwave background radiation. Comparison of the various existing redshift surveys emphasizes the need for systematic redshift surveys over significant areas of the sky out to intermediate and large distances. Although deep pencil-beam surveys are best suited for probing a large number of voids and walls, understanding the nature of the intercepted peaks and valleys in terms of large-scale structure requires that the angular coverage of the surveys be larger than the galaxy auto-correlation length. If this condition is not satisfied, the size of the voids and the density contrast of the walls can be overestimated.

Testing Cosmological Models with Clusters of Galaxies

10.1017/s0074180900132553 ◽

1999 ◽

Vol 183 ◽

pp. 221-228

Author(s):

S. Gottlöber ◽

J. Retzlaff ◽

A. Klypin

Keyword(s):

Statistical Tests ◽

Large Fraction ◽

Mass Scale ◽

Clusters Of Galaxies ◽

Matter Distribution ◽

Redshift Surveys ◽

The Galaxy ◽

Redshift Survey ◽

Formation And Evolution ◽

Currently little is known about the mass distribution on intermediate scales between those probed by deep redshift surveys of galaxies and those probed by COBE. Catalogs of galaxy clusters reach depths of several hundred megaparsecs, and, thus, are very useful for those scales. Only the Las Campanas Redshift Survey (LCRS) is comparable with that depth. However, the LCRS samples only narrow slices whereas cluster catalogs cover a large fraction of the sky. Clusters seems to be the most suitable objects to fill the gap between scales probed by COBE and the galaxy samples. Moreover, clusters are advantageous over galaxies as probes of the matter distribution in the Universe because our understanding of its formation and evolution is better established than it is for galaxies. Clusters are high peaks (mass scaleM≃ 1015M⊙) in the density field, which have collapsed relatively recently. Because of that, it is easy to identify clusters in numerical simulations. But the number of clusters is much smaller than the number of galaxies, which makes the statistics of clusters noisier. Nevertheless, clusters are exceptionally useful objects for the investigation of the matter distribution on scales well above 100h–1Mpc. Thus, it is worth to apply different statistical tests to these objects.

The Galaxy Distribution and the Large-Scale Structure of the Universe

Annals of the New York Academy of Sciences ◽

10.1111/j.1749-6632.1986.tb47970.x ◽

1986 ◽

Vol 470 (1 Twelfth Texas) ◽

pp. 123-135

Author(s):

MARGARET J. GELLER ◽

VALÉRIE LAPPARENT ◽

MICHAEL J. KURTZ

Keyword(s):

Large Scale ◽

Large Scale Structure ◽

Scale Structure ◽

Galaxy Distribution ◽

The Galaxy ◽

Detecting multi-scale filaments in galaxy distribution

Proceedings of the International Astronomical Union ◽

10.1017/s1743921314010680 ◽

2014 ◽

Vol 10 (S306) ◽

pp. 45-47

Author(s):

Elmo Tempel

Keyword(s):

Point Process ◽

Large Scale ◽

Three Dimensional ◽

Sloan Digital Sky Survey ◽

Point Distribution ◽

Multi Scale ◽

Galaxy Distribution ◽

Sky Survey ◽

The Galaxy ◽

Redshift Survey

AbstractThe main feature of the spatial large-scale galaxy distribution is its intricate network of galaxy filaments. This network is spanned by the galaxy locations that can be interpreted as a three-dimensional point distribution. The global properties of the point process can be measured by different statistical methods, which, however, do not describe directly the structure elements. The morphology of the large-scale structure, on the other hand, is an important property of the galaxy distribution. Here, we apply an object point process with interactions (the Bisous model) to trace and extract the filamentary network in the presently largest galaxy redshift survey, the Sloan Digital Sky Survey (SDSS data release 10). We search for multi-scale filaments in the galaxy distribution that have a radius of about 0.5, 1.0, 2.0, and 4.0h−1Mpc. We extract the spines of the filamentary network and divide the detected network into single filaments.

Measuring the VIPERS galaxy power spectrum at $z\sim1$

Proceedings of the International Astronomical Union ◽

10.1017/s1743921316009790 ◽

2014 ◽

Vol 11 (S308) ◽

pp. 169-171

Author(s):

Stefano Rota ◽

Julien Bel ◽

Ben Granett ◽

Luigi Guzzo

Keyword(s):

Power Spectrum ◽

Matter Density ◽

Spatial Sampling ◽

Volume Number ◽

Galaxy Distribution ◽

Data Release ◽

The Galaxy ◽

Redshift Survey ◽

First Time ◽

AbstractThe VIMOS Public Extragalactic Redshift Survey [VIPERS, Guzzo et al. 2014] is using the VIMOS spectrograph at the ESO VLT to measure redshifts for ∼ 100,000 galaxies with IAB < 22.5 and 0.5 < z < 1.2, over an area of 24 deg2 (split over the W1 and W4 fields of CFHTLS). VIPERS currently provides, at such redshifts, the best compromise between volume, number of galaxies and dense spatial sampling. We present here the first estimate of the power spectrum of the galaxy distribution, P(k), at redshifts z ∼ 0.75 and z ∼ 1, obtained from the ∼ 55,000 redshifts of the PDR-1 data release. We discuss first constraints on cosmological quantities, as the matter density and the baryonic fraction, obtained for the first time at an epoch when the Universe was about half its current age.

(Non-)fractality on Large Scales

10.1017/s0074180900216239 ◽

2005 ◽

Vol 201 ◽

pp. 168-177

Author(s):

Vicent J. Martínez

Keyword(s):

Large Scale ◽

Observational Evidence ◽

Statistical Analyses ◽

Gradual Transition ◽

Galaxy Distribution ◽

Small Scales ◽

The Galaxy ◽

The Subject ◽

The debate about the possible smoothness of the Universe on large scales as opposed to an unbounded fractal hierarchy has been the subject of increasing interest in recent years. The controversy arises as a consequence of different statistical analyses performed on surveys of galaxy redshifts. I review the observational evidence supporting the idea that a gradual transition occurs in the galaxy distribution: from a fractal regime at small scales to large scale homogeneity.

The Edinburgh/Durham Southern Galaxy Catalogue

10.1017/s0074180900135922 ◽

1988 ◽

Vol 130 ◽

pp. 125-127 ◽

Cited By ~ 1

Author(s):

C.A. Collins ◽

N. Heydon-Dumbleton ◽

H.T. Macgillivray ◽

T. Shanks

Keyword(s):

Data Base ◽

Density Fluctuation ◽

Current Status ◽

Initial Finding ◽

Unique Data ◽

Galaxy Distribution ◽

The Galaxy ◽

The Uk ◽

We review the current status of the Edinburgh/Durham southern galaxy catalogue. The aim of this project is to use COSMOS measurements of the UK Schmidt J survey to produce a unique data base of galaxies, complete down to bj ∼ 20.5 mag and covering ∼ 100 survey fields. We have developed the optimum procedures to classify objects as stars or galaxies and calibrate the galaxy magniudes on individual plates. We are confident that residual systematics will be ∼ 5%, thereby ensuring that this catalogue will substantially contribute to our understanding of the Universe at large. One initial finding of the survey is a probable 6 sigma density fluctuation in the galaxy distribution.

Large-Scale Flows in the Local Universe

10.1017/s0074180900110058 ◽

1996 ◽

Vol 168 ◽

pp. 175-182 ◽

Cited By ~ 1

Author(s):

D.S. Mathewson ◽

V.L. Ford

Keyword(s):

Large Scale ◽

Velocity Measurements ◽

Local Universe ◽

Peculiar Velocities ◽

Redshift Surveys ◽

Density Maps ◽

The Universe ◽

Great Wall ◽

Great Attractor ◽

Streaming Flow

Peculiar velocity measurements of 2500 southern spiral galaxies show large-scale flows in the direction of the Hydra-Centaurus clusters which fully participate in the flow themselves. The flow is not uniform over this region and seems to be associated with the denser regions which participate in the flow of amplitude about 400km/s. In the less dense regions the flow is small or non-existent. This makes the flow quite asymmetric and inconsistent with that expected from large-scale, parallel streaming flow that includes all galaxies out to 6000km/s as previously thought. The flow cannot be modelled by a Great Attractor at 4300km/s or the Centaurus clusters at 3500km/s. Indeed, from the density maps derived from the redshift surveys of “optical” and IRAS galaxies, it is difficult to see how the mass concentrations can be responsible particularly as they themselves participate in the flow. These results bring into question the generally accepted reason for the peculiar velocities of galaxies that they arise solely as a consequence of infall into the dense regions of the universe. To the N. of the Great Attractor region, the flow increases and shows no sign of diminishing out to the redshift limit of 8000km/s in this direction. We may have detected flow in the nearest section of the Great Wall.

Investigating the properties of a galaxy group at z = 0.6

Proceedings of the International Astronomical Union ◽

10.1017/s1743921320001945 ◽

2020 ◽

Vol 15 (S359) ◽

pp. 188-189

Author(s):

Daniela Hiromi Okido ◽

Cristina Furlanetto ◽

Marina Trevisan ◽

Mônica Tergolina

Keyword(s):

Large Scale ◽

The Other ◽

Numerical Density ◽

Spectroscopy Data ◽

Stellar Kinematics ◽

Galaxy Groups ◽

The Galaxy ◽

The Difference ◽

The Impact ◽

AbstractGalaxy groups offer an important perspective on how the large-scale structure of the Universe has formed and evolved, being great laboratories to study the impact of the environment on the evolution of galaxies. We aim to investigate the properties of a galaxy group that is gravitationally lensing HELMS18, a submillimeter galaxy at z = 2.39. We obtained multi-object spectroscopy data using Gemini-GMOS to investigate the stellar kinematics of the central galaxies, determine its members and obtain the mass, radius and the numerical density profile of this group. Our final goal is to build a complete description of this galaxy group. In this work we present an analysis of its two central galaxies: one is an active galaxy with z = 0.59852 ± 0.00007, while the other is a passive galaxy with z = 0.6027 ± 0.0002. Furthermore, the difference between the redshifts obtained using emission and absorption lines indicates an outflow of gas with velocity v = 278.0 ± 34.3 km/s relative to the galaxy.