scholarly journals HOW LARGE IS THE CONTRIBUTION OF COSMIC WEB TO ΩΛ? A PRELIMINARY STUDY ON A NOVEL INHOMOGENEOUS MODEL

2013 ◽  
Vol 22 (10) ◽  
pp. 1350065 ◽  
Author(s):  
STEFANO VIAGGIU ◽  
MARCO MONTUORI
Keyword(s):  
Large Scale ◽  
Large Fraction ◽  
Cosmological Parameters ◽  
The Other ◽  
Matter Distribution ◽  
Cluster Of Galaxies ◽  
Λcdm Model ◽  
Standard Values ◽  
Preliminary Study ◽  
The Universe

The distribution of matter in the universe shows a complex pattern, formed by cluster of galaxies, voids and filaments denoted as cosmic web. Different approaches have been proposed to model such structure in the framework of the general relativity. Recently, one of us has proposed a generalization (ΛFB model) of the Fractal Bubble model, proposed by Wiltshire, which accounts for such large scale structure. The ΛFB model is an evolution of FB model and includes in a consistent way a description of inhomogeneous matter distribution and a Λ term. Here, we analyze the ΛFB model focusing on the relation between cosmological parameters. The main result is the consistency of ΛCDM model values for ΩΛ0 (≈ 0.7) and Ωk0(∣Ωk0∣ < ≈ 0.01) with a large fraction of voids. This allows to quantify to which extent the inhomogeneous structure could account for Λ constant consistently with standard values of the other cosmological parameters.

scholarly journals SCALING IN COSMIC STRUCTURES

Fractals ◽  
2003 ◽  
Vol 11 (supp01) ◽  
pp. 271-279 ◽  
Author(s):  
LUCIANO PIETRONERO ◽  
MAURIZIO BOTTACCIO ◽  
MARCO MONTUORI ◽  
FRANCESCO SYLOS LABINI
Keyword(s):  
Large Scale ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Statistical Properties ◽  
The Other ◽  
Matter Distribution ◽  
Modern Cosmology ◽  
Correlation Properties ◽  
The Universe

The study of the properties of cosmic structures in the universe is one of the most fascinating subject of the modern cosmology research. Far from being predicted, the large scale structure of the matter distribution is a very recent discovery, which continuosly exhibits new features and issues. We have faced such topic along two directions; from one side we have studied the correlation properties of the cosmic structures, that we have found substantially different from the commonly accepted ones. From the other side, we have studied the statistical properties of the very simplified system, in the attempt to capture the essential ingredients of the formation of the observed strucures.

Cosmological spacetimes

2018 ◽  
Author(s):  
Nathalie Deruelle ◽  
Jean-Philippe Uzan
Keyword(s):  
Cosmological Model ◽  
Large Scale ◽  
Cosmic Time ◽  
De Sitter ◽  
Matter Distribution ◽  
Observable Universe ◽  
Cosmological Principle ◽  
Riemannian Spacetime ◽  
The Universe ◽  
Copernican Principle

This chapter provides a few examples of representations of the universe on a large scale—a first step in constructing a cosmological model. It first discusses the Copernican principle, which is an approximation/hypothesis about the matter distribution in the observable universe. The chapter then turns to the cosmological principle—a hypothesis about the geometry of the Riemannian spacetime representing the universe, which is assumed to be foliated by 3-spaces labeled by a cosmic time t which are homogeneous and isotropic, that is, ‘maximally symmetric’. After a discussion on maximally symmetric space, this chapter considers spacetimes with homogenous and isotropic sections. Finally, this chapter discusses Milne and de Sitter spacetimes.

scholarly journals Investigating the properties of a galaxy group at z = 0.6

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 ◽  
The Universe

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.

scholarly journals The Theory of the Large Scale Structure of the Universe

1978 ◽  
Vol 79 ◽  
pp. 409-421 ◽  
Author(s):  
Ya B. Zeldovich
Keyword(s):  
Early Childhood ◽  
Sigmund Freud ◽  
Large Scale ◽  
Large Scale Structure ◽  
Scale Structure ◽  
The Other ◽  
Childhood Experiences ◽  
Other Hand ◽  
The Universe ◽  
Single Statement

The God-father of psychoanalysis Professor Sigmund Freud taught us that the behaviour of adults depends on their early childhood experiences. in the same spirit, the problem of cosmological analysis is to derive the observed present day situation and structure of the Universe from certain plausible assumptions about its early behaviour. Perhaps the most important single statement about the large scale structure is that there is no structure at all on the largest scale − 1000 Mpc and more. On this scale the Universe is rather uniform, structureless and isotropically expanding - just according to the simplified pictures of Einstein-Friedmann……. Humason, Hubble…. Robertson, Walker. On the other hand there is a lot of structure on the scale of 100 or 50 Mpc and less. There are clusters and superclusters of galaxies.

scholarly journals The AAO 2DF QSO Redshift Survey

1999 ◽  
Vol 183 ◽  
pp. 178-184 ◽  
Author(s):  
B.J. Boyle ◽  
R.J. Smith ◽  
T. Shanks ◽  
S.M. Croom ◽  
L. Miller
Keyword(s):  
Large Scale ◽  
Cosmological Parameters ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Redshift Survey ◽  
The Universe

The study of large-scale structure through QSO clustering provides a potentially powerful route to determining the fundamental cosmological parameters of the Universe (see Croom & Shanks 1996). Unfortunately, previous QSO clustering studies have been limited by the relatively small sizes of homogeneous QSO catalogues that have been available. Although approximately 10,000 QSOs are now known (Veron-Cetty & Veron 1997), the largest catalogues suitable for clustering studies contain only 500–1000 QSOs (Boyle et al. 1990, Crampton et al. 1990, Hewett et al. 1994). Even combining all such suitable catalogues, the total number of QSOs which can be used for clustering studies is still only about 2000.

scholarly journals Isotropization of Homogeneous Cosmological Models

1974 ◽  
Vol 63 ◽  
pp. 273-282
Author(s):  
I. D. Novikov
Keyword(s):  
Large Scale ◽  
Background Radiation ◽  
Cosmological Models ◽  
Matter Distribution ◽  
Cosmological Singularity ◽  
Universe Expand ◽  
Starting Point ◽  
Microwave Background Radiation ◽  
Friedmann Cosmological Models ◽  
The Universe

Observations primarily of the microwave background radiation show that the Universe expands isotropically with a high degree of accuracy at the present time and that the matter distribution is homogeneous on a large scale. Thus, the Friedmann cosmological models are a good approximation today for the expanding Universe. This is valid for at least some period of time in the past too. But how did the Universe expand and what was the matter distribution close to the starting point, near the cosmological singularity?

scholarly journals The Dust Impact on the Intergalactic Medium

2004 ◽  
Vol 217 ◽  
pp. 114-115
Author(s):  
L. Montier ◽  
M. Giard
Keyword(s):  
Large Scale ◽  
Intergalactic Medium ◽  
High Redshift ◽  
Dust Emission ◽  
The Other ◽  
Heating And Cooling ◽  
Cooling Agent ◽  
Small Scales ◽  
The Impact ◽  
The Universe

Recent observations at low and high redshift seem to confirm the presence of dust at very low abundances in the InterGalactic Medium (IGM) and especially in the IntraCluster Medium (ICM). We have studied the impact of this dust on the IGM, in terms of heating and cooling. on one hand, with an analytical model of dust emission, we have proved that the dust can be considered as the dominant cooling agent of the ICM at large scale, when the temperature is greater than T = 107 K. on the other hand, with a strong UV Background and a low temperature (Te ≤ 105 K), dust grains become an efficient heating agent of the IGM. These two opposite effects may have played an important role regarding structure formation of the Universe at large and small scales.

scholarly journals GRAVITATIONAL LENSING BOUND ON THE AVERAGE REDSHIFT OF GAMMA RAY BURSTS IN MODELS WITH EVOLVING LENSES

1999 ◽  
Vol 08 (04) ◽  
pp. 507-517 ◽  
Author(s):  
DEEPAK JAIN ◽  
N. PANCHAPAKESAN ◽  
S. MAHAJAN ◽  
V. B. BHATIA
Keyword(s):  
Gravitational Lensing ◽  
Gamma Ray ◽  
Cosmological Parameters ◽  
Evolutionary Model ◽  
Gamma Ray Bursts ◽  
The Other ◽  
Upper Limit ◽  
Evolving Model ◽  
Evolving Models ◽  
The Universe

Identification of gravitationally lensed Gamma Ray Bursts (GRBs) in the BATSE 4B catalog can be used to constrain the average redshift <z> of the GRBs. In this paper we investigate the effect of evolving lenses on the <z> of GRBs in different cosmological models of the universe. The cosmological parameters Ω and Λ have an effect on the <z> of GRBs. The other factor which can change the <z> is the evolution of galaxies. We consider three evolutionary model of galaxies. In particular, we find that the upper limit on <z> of GRBs is higher in evolving model of galaxies as compared to non-evolving models of galaxies.

Observational and astrophysical cosmology: 1980–2018

2019 ◽  
pp. 375-423
Author(s):  
Malcolm S. Longair
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Cosmological Constant ◽  
Large Scale ◽  
Cosmological Parameters ◽  
Semiconductor Detectors ◽  
Empirical Knowledge ◽  
Global Geometry ◽  
The Universe ◽  
Large Scale Structure Formation

Since 1980, our empirical knowledge of the universe has advanced tremendously and precision cosmology has become a reality. These developments have been largely technology-driven, the result of increased computer power, new generations of telescopes for all wavebands, new types of semiconductor detectors, such as CCDs, and major investments by many nations in superb observing facilities. The discipline also benefitted from the influx of experimental and theoretical physicists into the cosmological arena. The accuracy and reliability of the values of the cosmological parameters has improved dramatically, many of them now being known to about 1%. The ΛCDM model provides a remarkable fit to all the observational data, demonstrating that the cosmological constant is non-zero and that the global geometry of the universe is flat. The underlying physics of galaxy and large-scale structure formation has advanced dramatically and demonstrated the key roles played by dark matter and dark energy.

scholarly journals Relativistic plasma and ICM/radio source interaction

2010 ◽  
Vol 6 (S274) ◽  
pp. 340-347 ◽  
Author(s):  
Luigina Feretti ◽  
Gabriele Giovannini ◽  
Federica Govoni ◽  
Matteo Murgia
Keyword(s):  
Magnetic Fields ◽  
Radio Source ◽  
Large Scale ◽  
Large Scale Structure ◽  
Radio Sources ◽  
Relativistic Electrons ◽  
Coma Cluster ◽  
Cluster Of Galaxies ◽  
Formation And Evolution ◽  
The Universe

AbstractThe first detection of a diffuse radio source in a cluster of galaxies, dates back to the 1959 (Coma Cluster, Large et al. 1959). Since then, synchrotron radiating radio sources have been found in several clusters, and represent an important cluster component which is linked to the thermal gas. Such sources indicate the existence of large scale magnetic fields and of a population of relativistic electrons in the cluster volume. The observational results provide evidence that these phenomena are related to turbulence and shock-structures in the intergalactic medium, thus playing a major role in the evolution of the large scale structure in the Universe. The interaction between radio sources and cluster gas is well established in particular at the center of cooling core clusters, where feedback from AGN is a necessary ingredient to adequately describe the formation and evolution of galaxies and host clusters.

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