Large-Scale Structures from Low-Resolution Redshift Surveys

Author(s):  
Peter Schuecker ◽  
Heinz-Albert Ott ◽  
Waltraut C. Seitter
1987 ◽  
Vol 124 ◽  
pp. 383-388
Author(s):  
David C. Koo ◽  
Richard G. Kron

This paper reports preliminary results of two long-term redshift surveys that are near completion. One consists of nearly 400 redshifts of field galaxies; the sample is faint enough (B ≲ 22) to test models of galaxy luminosity and color evolution (and possibly cosmology) and to search for the presence of very large-scale structures among distant field galaxies. The other consists of over 60 spectra of quasar candidates of similar faintness; the identifications and redshifts of bona-fide quasars provide strong constraints on the evolution and shape of the luminosity function of distant quasars. Almost all of the observations have been made with the 4m telescope at Kitt Peak National Observatory with the Cryogenic Camera in multiaperture mode. The spectral range covered 4500Å to 7500Å with 15Å FWHM resolution and 4Å per pixel; simultaneous exposures of an hour or two were made for about 10 objects within the 5 arcmin field of view.


2014 ◽  
Vol 11 (S308) ◽  
pp. 299-300
Author(s):  
Shishir Sankhyayan ◽  
J. Bagchi ◽  
P. Sarkar ◽  
V. Sahni ◽  
J. Jacob

AbstractWe have initiated the search and detailed study of large scale structures present in the universe using galaxy redshift surveys. In this process, we take the volume-limited sample of galaxies from Sloan Digital Sky Survey III and find very large structures even beyond the redshift of 0.2. One of the structures is even greater than 600 Mpc which raises a question on the homogeneity scale of the universe. The shapes of voids-structures (adjacent to each other) seem to be correlated, which supports the physical existence of the observed structures. The other observational supports include galaxy clusters' and QSO distribution's correlation with the density peaks of the volume limited sample of galaxies.


1999 ◽  
Vol 173 ◽  
pp. 243-248
Author(s):  
D. Kubáček ◽  
A. Galád ◽  
A. Pravda

AbstractUnusual short-period comet 29P/Schwassmann-Wachmann 1 inspired many observers to explain its unpredictable outbursts. In this paper large scale structures and features from the inner part of the coma in time periods around outbursts are studied. CCD images were taken at Whipple Observatory, Mt. Hopkins, in 1989 and at Astronomical Observatory, Modra, from 1995 to 1998. Photographic plates of the comet were taken at Harvard College Observatory, Oak Ridge, from 1974 to 1982. The latter were digitized at first to apply the same techniques of image processing for optimizing the visibility of features in the coma during outbursts. Outbursts and coma structures show various shapes.


2015 ◽  
Vol 12 (108) ◽  
pp. 20150044 ◽  
Author(s):  
Dervis C. Vural ◽  
Alexander Isakov ◽  
L. Mahadevan

Starting with Darwin, biologists have asked how populations evolve from a low fitness state that is evolutionarily stable to a high fitness state that is not. Specifically of interest is the emergence of cooperation and multicellularity where the fitness of individuals often appears in conflict with that of the population. Theories of social evolution and evolutionary game theory have produced a number of fruitful results employing two-state two-body frameworks. In this study, we depart from this tradition and instead consider a multi-player, multi-state evolutionary game, in which the fitness of an agent is determined by its relationship to an arbitrary number of other agents. We show that populations organize themselves in one of four distinct phases of interdependence depending on one parameter, selection strength. Some of these phases involve the formation of specialized large-scale structures. We then describe how the evolution of independence can be manipulated through various external perturbations.


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