scholarly journals Clusters of Galaxies

1980 ◽  
Vol 5 ◽  
pp. 699-714 ◽  
Author(s):  
Neta A. Bahcall
Keyword(s):  
Large Scale ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Clusters Of Galaxies ◽  
Groups Of Galaxies ◽  
Formation And Evolution ◽  
The Rich ◽  
The Many ◽  
The Universe

AbstractClusters and groups of galaxies contain the majority of galaxies in the universe. The rich clusters, while less numerous than the many poor groups, are the densest and largest systems known, and can be easily recognized and studied even at relatively large distances. Their study is important for understanding the formation and evolution of clusters and galaxies, and for a determination of the large-scale structure in the universe.

scholarly journals Large-Scale Structure in the Universe: Spatial Distribution and Peculiar Velocities

1987 ◽  
Vol 124 ◽  
pp. 335-348
Author(s):  
Neta A. Bahcall
Keyword(s):  
Dark Matter ◽  
Spatial Distribution ◽  
Large Scale ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Clusters Of Galaxies ◽  
Large Scale Structures ◽  
Peculiar Velocities ◽  
Scale Structures ◽  
The Universe

The evidence for the existence of very large scale structures, ∼ 100h−1Mpc in size, as derived from the spatial distribution of clusters of galaxies is summarized. Detection of a ∼ 2000 kms−1 elongation in the redshift direction in the distribution of the clusters is also described. Possible causes of the effect are peculiar velocities of clusters on scales of 10–100h−1Mpc and geometrical elongation of superclusters. If the effect is entirely due to the peculiar velocities of clusters, then superclusters have masses of order 1016.5M⊙ and may contain a larger amount of dark matter than previously anticipated.

Formation Times for Rich Clusters of Galaxies

1977 ◽  
Vol 3 (2) ◽  
pp. 140-142 ◽  
Author(s):  
B. M. Lewis
Keyword(s):  
Gaussian Distribution ◽  
Large Scale ◽  
Velocity Dispersion ◽  
Large Scale Structure ◽  
Elliptical Galaxies ◽  
Scale Structure ◽  
Clusters Of Galaxies ◽  
Number Density ◽  
Radial Gradient ◽  
The Universe

Rich clusters of galaxies are a common feature of the large-scale structure of the Universe. Those studied so far, show striking regularities with (a)a smooth radial gradient of number density.(b)’isothermal’ distributions, which according to Bahcall (1975) have a scatter of only ±15% in the size of their characteristic core radii.(c)their limiting structural diameters are ~50 Mpc (cf. Abell, 1975), if they are identified with superclusters.(d)the magnitude of the velocity dispersion about their centres is generally 600-1000 km s-1, and the velocities are cpnsistent with a gaussian distribution (Yahil and Vidal, 1976; also Faber and Dressier, 1976).(e)The extreme velocities are generally within ±3000 km s-1, and for Coma are ∼2400 km s-1 (Tifft and Gregory, 1976).(f)elliptical galaxies tend to predominate near the centre, spirals in the surrounding loose groups.

scholarly journals Large Scale Structure of the Universe

1998 ◽  
Vol 179 ◽  
pp. 317-328 ◽  
Author(s):  
N.A. Bahcall
Keyword(s):  
Large Scale ◽  
Initial Conditions ◽  
Large Scale Structure ◽  
Density Fluctuations ◽  
Scale Structure ◽  
Sloan Digital Sky Survey ◽  
Sky Survey ◽  
Initial Spectrum ◽  
Formation And Evolution ◽  
The Universe

How is the universe organized on large scales? How did this structure evolve from the unknown initial conditions of a rather smooth early universe to the present time? The answers to these questions will shed light on the cosmology we live in, the amount, composition and distribution of matter in the universe, the initial spectrum of density fluctuations that gave rise to this structure, and the formation and evolution of galaxies, lusters of galaxies, and larger scale structures.To address these fundamental questions, large and accurate sky surveys are needed—in various wavelengths and to various depths. In this presentation I review current observational studies of large scale structure, present the constraints these observations place on cosmological models and on the amount of dark matter in the universe, and highlight some of the main unsolved problems in the field of large-scale structure that could be solved over the next decade with the aid of current and future surveys. I briefly discuss some of these surveys, including the Sloan Digital Sky Survey that will provide a complete imaging and spectroscopic survey of the high-latitude northern sky, with redshifts for the brightest ∼ 106 galaxies, 105 quasars, and 103.5 rich clusters of galaxies. The potentialities of the SDSS survey, as well as of cross-wavelength surveys, for resolving some of the unsolved problems in large-scale structure and cosmology are discussed.

scholarly journals Determination of the large-scale and super-large-scale structure by means of the space distribution of quasars

1986 ◽  
Vol 119 ◽  
pp. 495-496
Author(s):  
Y.Y. Zhou ◽  
D.P. Fang ◽  
Z.G. Deng ◽  
X.T. He
Keyword(s):  
Large Scale ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Space Distribution ◽  
The Universe

It is very important to study the large-scale structure by means of the space distribution of quasars. Using this method, one may search for the more distant superclusters and explore the super-large-scale structure, i.e., the existence of super-superclusters. The answer to the problem would be of great interest. It is related to the question about the transition of the clustering of galaxies on about 100 Mpc to the uniformity of the universe. Recently Oort et al and de Ruiter et al suggested that the quasars are located in superclusters. So we soppose that analysing the space distribution of quasars might give us some information about the super-large-scale structure of the universe. But up to the present the study of the clustering of quasars has not obtained universally accepted conclusions; in fact, some of them, including grouping and clustering (Arp; Chu and Zhu), no clustering (Chu and Zhu; Osmer; Webster), clustering for z < 2 and no clustering for z > 2 (Fang et al) and stringing (Deng et al), are contradictory.

scholarly journals DIVISION VIII: GALAXIES AND THE UNIVERSE

2008 ◽  
Vol 4 (T27A) ◽  
pp. 283-285
Author(s):  
Sadanori Okamura ◽  
Elaine Sadler ◽  
Francesco Bertola ◽  
Mark Birkinshaw ◽  
Françoise Combes ◽  
...  
Keyword(s):  
Computer Simulations ◽  
Large Scale ◽  
Background Radiation ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Clusters Of Galaxies ◽  
Microwave Background ◽  
Wide Range ◽  
Microwave Background Radiation ◽  
The Universe

Division VIII provides a focus for astronomers studying a wide range of problems related to galaxies and cosmology. Objects of the study include individual galaxies, groups and clusters of galaxies, large scale structure, comic microwave background radiation and the universe itself. Approaches are diverse from observational one to theoretical one including computer simulations.

scholarly journals A Unified Picture of Large-Scale Structure

1992 ◽  
Vol 9 ◽  
pp. 671-680
Author(s):  
Neta A. Bahcall
Keyword(s):  
Cellular Structure ◽  
Large Scale ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Low Density ◽  
Pencil Beam ◽  
Clusters Of Galaxies ◽  
Different Types ◽  
Consistent Picture ◽  
The Universe

AbstractA consistent picture of large-scale structure appears to be emerging from different types of observations including the spatial distribution of galaxies, clusters of galaxies, narrow pencil-beam surveys, and quasars. I describe these observations below. A network of large-scale superclusters, up to ~ 150 Mpc in scale, is suggested. The supercluster network surrounds low-density regions of similar scales, suggesting a “cellular” structure of the universe. (Ho = 100 km /s/ Mpc is used).

scholarly journals The Distribution of BCDGs in Voids

1998 ◽  
Vol 11 (1) ◽  
pp. 111-112
Author(s):  
Ulrich Lindner ◽  
Klaus J. Fricke ◽  
Jaan Einasto ◽  
Maret Einasto
Keyword(s):  
Galaxy Clusters ◽  
Small Groups ◽  
Large Scale ◽  
Dwarf Galaxies ◽  
Large Scale Structure ◽  
Elliptical Galaxies ◽  
Scale Structure ◽  
Clusters Of Galaxies ◽  
Late Type ◽  
Formation And Evolution

Generally the density of the environment is important for the formation and evolution of galaxies: bright elliptical galaxies reside in the centers of galaxy clusters, whereas late type galaxies preferentially populate small groups, filaments or the outskirts of rich clusters of galaxies. Furthermore, fainter galaxies define smaller voids than bright galaxies. Our investigation of void catalogues in the Northern Local Void region shows that large voids are interlaced by systems of faint galaxies dividing them into smaller subvoids (Lindner et al., 1995). This void hierarchy is an important property of the Large Scale Structure in the nearby Universe and can help to solve problems concerning the distribution of dwarf galaxies and BCDGs.

scholarly journals The internal structure of protoclusters and the formation of galaxies

1978 ◽  
Vol 79 ◽  
pp. 423-425 ◽  
Author(s):  
A. G. Doroshkevich ◽  
E. M. Saar ◽  
S. F. Shandarin
Keyword(s):  
Internal Structure ◽  
Large Scale ◽  
Large Scale Structure ◽  
Short Review ◽  
Scale Structure ◽  
Clusters Of Galaxies ◽  
General Picture ◽  
Adiabatic Theory ◽  
The Universe

We give a short review of the general picture and main features of the formation of galaxies and clusters of galaxies on the basis of the adiabatic theory. Detailed discussions of these questions are published in references 1–6. Some related problems of the formation and development of large scale structure in the Universe according to the same theory are considered in Zeldovich's report.

scholarly journals Data retrieval in the metacatalogue of galaxies

1982 ◽  
Vol 64 ◽  
pp. 261-263
Author(s):  
M. Kalinkov ◽  
I. Kuneva ◽  
K. Stavrev
Keyword(s):  
Magnetic Tape ◽  
Large Scale ◽  
Data Retrieval ◽  
Data Bank ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Clusters Of Galaxies ◽  
Homogeneous Systems ◽  
New Type ◽  
The Universe

To study the large scale structure of the Universe, we started several years ago the compilation of a new type of catalogue – a metacatalogue of optical extragalactic objects, on magnetic tape. This catalogue may be regarded to some extent as a data bank but it will also include characteristics, reduced to homogeneous systems. The Metacatalogue will contain information for galaxies, clusters of galaxies, counts of galaxies and bibliographical data. Until now some files for individual catalogues and lists have been created, which may be used also before their merging into the Metacatalogue.

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