scholarly journals Mapping the Large-Scale Structure

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.

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 Tracing Large-Scale Structure with Galaxy Objective-Prism Spectra

1988 ◽  
Vol 130 ◽  
pp. 525-525
Author(s):  
Q.A. Parker ◽  
H.T. Macgillivray ◽  
S.M. Beard
Keyword(s):  
Large Scale ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Early Type ◽  
Galaxy Distribution ◽  
Large Numbers ◽  
The Galaxy ◽  
Measured Sample ◽  
Objective Prism ◽  
Low Dispersion

A new and promising use of galaxy objective-prism spectra as a means of highlighting features in the large scale galaxy distribution has been recently reported by Parker et al. (1987). The technique relies on the property that galaxies with identifiable 4000Å features in low dispersion objective-prism spectra are mostly ellipticals (Cooke, 1980), and that early type galaxies seem to delineate structure and clumpiness in the galaxy distribution (e.g. Giovanelli and Haynes, 1982). The effect is most striking when large numbers of objective-prism galaxy spectra are considered. Figure 1 gives the X-Y plot for 1539 galaxies with 4000Å features to Bj=18.7 in one UKST field out of a manually measured sample of 2903 galaxy prism spectra. Substantial clumpiness is evident. This technique can trace structure in the galaxy distribution across many UKST fields to depths of 400 h−1Mpc.

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

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 ◽  
The Universe

scholarly journals Cosmology (Cosmologie)

1991 ◽  
Vol 21 (1) ◽  
pp. 561-580
Keyword(s):  
Cosmic Microwave Background ◽  
Large Scale ◽  
Background Radiation ◽  
Cosmological Parameters ◽  
Large Scale Structure ◽  
Cosmic Microwave Background Radiation ◽  
Scale Structure ◽  
Microwave Background ◽  
Structure And Motion ◽  
Microwave Background Radiation

The last three years have been very fruitful ones in cosmology research. Brilliant achievement on the spectrum and homogeneities of cosmic microwave background radiation by COBE satellite is an example. It is, however, obviously impossible to review achievements in all fields in the number of pages allocated to our commission. This report, as in past reports, consists of some details of only some selected topics. I invited six active colleagues to collaborate in the preparation of this report. The topics are 1) Large Scale Structure and Motion (A. Dekel), 2) Formation of Galaxies and Large Scale Structure (S. Shandarin), 3) Active Galactic Nuclei in Cosmology (P.A. Shaver), 4) Cosmic Microwave Background Radiation (R. B. Partridge), 5) Primordial Nucleosynthesis (H. Reeves) and 6)The Cosmological Parameters (V. Trimble). Unfortunately, review on Early Universe could not be included because of the limit of page number, though it was planned originally. Recent developments in this area would be seen in the proceedings of recent international conferences (for example, Nobel Symposium 79 on ”The Birth and Early Evolution of Our Universe” Graeftavallen, Sweden, June, 1990, ed. B.-S. Skagerstam, World Scientific)

Origin and evolution of the large-scale structure of the universe

1990 ◽  
Vol 68 (9) ◽  
pp. 799-807
Author(s):  
Joseph Silk
Keyword(s):  
Large Scale ◽  
Background Radiation ◽  
Building Blocks ◽  
Large Scale Structure ◽  
Big Bang ◽  
Scale Structure ◽  
Observational Cosmology ◽  
Spontaneous Breaking ◽  
Fluctuation Spectrum ◽  
The Universe

Ever since the epoch of the spontaneous breaking of grand unification symmetry between the nuclear and electromagnetic interactions, the universe has expanded under the imprint of a spectrum of density fluctuations that is generally considered to have originated in this phase transition. I will discuss various possibilities for the form of the primordial fluctuation spectrum, spanning the range of adiabatic fluctuations, isocurvature fluctuations, and cosmic strings. Growth of the seed fluctuations by gravitational instability generates the formation of large-scale structures, from the scale of galaxies to that of clusters and superclusters of galaxies. There are three areas of confrontation with observational cosmology that will be reviewed. The large-scale distribution of the galaxies, including the apparent voids, sheets and filaments, and the coherent peculiar velocity field on scales of several tens of megaparsecs, probe the primordial fluctuation spectrum on scales that are only mildly nonlinear. Even larger scales are probed by study of the anisotropy of the cosmic microwave background radiation, which provides a direct glimpse of the primordial fluctuations that existed about 106 years or so after the initial big bang singularity. Galaxy formation is the process by which the building blocks of the universe have formed, involving a complex interaction between hydrodynamical and dynamical processes in a collapsing gas cloud. Both by detection of forming galaxies in the most remote regions of the universe and by study of the fundamental morphological characteristics of galaxies, which provide a fossilized memory of their past, can one relate the origin of galaxies to the same primordial fluctuation spectrum that gave rise' to the large-scale structure of the universe.

scholarly journals Large-scale structure of the Magellanic Clouds using planetary nebulae

1991 ◽  
Vol 148 ◽  
pp. 89-95
Author(s):  
S. J. Meatheringham
Keyword(s):  
Large Scale ◽  
Planetary Nebulae ◽  
Large Scale Structure ◽  
Magellanic Clouds ◽  
Scale Structure ◽  
The Galaxy ◽  
Young Clusters

The Small and Large Magellanic Clouds (SMC, LMC) are of considerable interest from a kinematical viewpoint. The tidal interation of the Clouds with each other and with the Galaxy appears to have been quite significant in recent times (Murai & Fujimoto 1980). The SMC in particular appears to have been considerably disrupted by a recent close passage to the LMC (Mathewson & Ford 1984, Mathewson 1984, Mathewson et al. 1986). For the LMC Freeman et al. (1983) found that the young and old populations have significantly different rotation solutions.Planetary Nebulae (PN) form a population with age intermediate between the HI and young clusters and the old Population II clusters. A large number of PN are known in the MCs. Sanduleak et al. (1978) compiled a list of 102 in the LMC and 28 in the SMC. Since then other authors have increased the total number known to approximately 140 in the LMC and 50 in the SMC.

scholarly journals Faint Structures in Low Density Regions of the Nearby Universe

1999 ◽  
Vol 183 ◽  
pp. 256-256
Author(s):  
U. Lindner ◽  
K.J. Fricke ◽  
J. Einasto ◽  
M. Einasto
Keyword(s):  
Large Scale ◽  
Large Scale Structure ◽  
Morphological Type ◽  
High Density ◽  
Low Density ◽  
Clusters Of Galaxies ◽  
Galaxy Distribution ◽  
The Galaxy ◽  
Empty Sphere ◽  
First Time

We present an investigation of the galaxy distribution in the huge underdense region between the Hercules, Coma and Local Superclusters, the so-called Northern Local Void (NLV), using void statistics (for details refer to Lindner et al. this Volume). Reshift data for galaxies and poor clusters of galaxies are available in low and high density regions as well. Samples of galaxies with different morphological type and various luminosity limits have been studied separately and void catalogues have been compiled from three different luminosity limited galaxy samples for the first time. Voids have been found using the empty sphere method which has the potential to detect and describe subtle structures in the galaxy distribution. Our approach is complementary to most other methods usually used in Large–Scale Structure studies.

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