Cosmological Tests for Minimally Coupled Perturbed Dark Energy

2010 ◽  
Author(s):  
S. Apunevych ◽  
B. Novosyadlyj ◽  
O. Sergijenko
Keyword(s):  
Dark Energy ◽  
Cosmological Tests

scholarly journals Gravitational Energy as Dark Energy: Concordance of Cosmological Tests

2007 ◽  
Vol 672 (2) ◽  
pp. L91-L94 ◽  
Author(s):  
Ben M. Leith ◽  
S. C. Cindy Ng ◽  
David L. Wiltshire
Keyword(s):  
Dark Energy ◽  
Gravitational Energy ◽  
Cosmological Tests

scholarly journals DARK ENERGY AND THE STATISTICAL STUDY OF THE OBSERVED IMAGE SEPARATIONS OF THE MULTIPLY-IMAGED SYSTEMS IN THE CLASS STATISTICAL SAMPLE

2004 ◽  
Vol 13 (06) ◽  
pp. 1005-1018 ◽  
Author(s):  
ABHA DEV ◽  
DEEPAK JAIN ◽  
SHOBHIT MAHAJAN
Keyword(s):  
Dark Energy ◽  
Statistical Study ◽  
Cosmological Parameters ◽  
Mass Scale ◽  
Gravitational Lens ◽  
Radio Sources ◽  
Sky Survey ◽  
Image Separation ◽  
Cosmological Tests ◽  
Statistical Sample

The present day observations favour a universe which is flat, accelerated and composed of ~ 1/3 matter (baryonic + dark) and ~ 2/3 of a negative pressure component, usually referred to as dark energy or quintessence. The Cosmic Lens All Sky Survey (CLASS), the largest radio-selected galactic mass scale gravitational lens search project to date, has resulted in the largest sample suitable for statistical analysis. In the work presented here, we exploit observed image separations of the multiply-imaged lensed radio sources in the sample. We use two different tests: (1) image separation distribution function n(Δθ) of the lensed radio sources and (2) Δθ pred versus Δθ obs as observational tools to constrain the cosmological parameters w and Ωm. The results are in concordance with the bounds imposed by other cosmological tests.

scholarly journals Unveiling cosmography from the dark energy equation of state

2019 ◽  
Vol 28 (12) ◽  
pp. 1950154 ◽  
Author(s):  
Celia Escamilla-Rivera ◽  
Salvatore Capozziello
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Energy Equation ◽  
Cosmological Parameters ◽  
Cosmic Acceleration ◽  
Type Ia ◽  
State Formula ◽  
Cosmological Tests ◽  
Supernovae Type Ia ◽  
Straightforward Approach

Constraining the dark energy equation of state, [Formula: see text], is one of the main issues of current and future cosmological surveys. In practice, this requires making assumptions about the evolution of [Formula: see text] with redshift [Formula: see text], which can be manifested in a choice of a specific parametric form where the number of cosmological parameters play an important role in the observed cosmic acceleration. Since any attempt to constrain the EoS requires some prior fixing in one form or the other, settling a method to constrain cosmological parameters is of great importance. In this paper, we provide a straightforward approach to show how cosmological tests can be improved via a parametric methodology based on cosmography. Using Supernovae Type IA samplers, we show how by performing a statistical analysis of a specific dark energy parametrization can give directly the cosmographic parameters values.

scholarly journals DARK ENERGY, DARK MATTER AND GRAVITY

2007 ◽  
Vol 16 (12a) ◽  
pp. 2003-2012 ◽  
Author(s):  
ORFEU BERTOLAMI
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Solar System ◽  
Physical Theory ◽  
Scalar Fields ◽  
High Accuracy ◽  
Scalar Theory ◽  
General Relativistic ◽  
Cosmological Tests ◽  
Theory Of Gravity

We discuss the motivation for high accuracy relativistic gravitational experiments in the solar system and complementary cosmological tests. We focus our attention on the issue of distinguishing a generic scalar theory of gravity as the underlying physical theory from the usual general-relativistic picture, where one expects the presence of fundamental scalar fields associated, for instance, with inflation, dark matter and dark energy.

scholarly journals GRAVITATIONAL LENSING STATISTICAL PROPERTIES IN GENERAL FRW COSMOLOGIES WITH DARK ENERGY COMPONENT(S): ANALYTIC RESULTS

2000 ◽  
Vol 09 (05) ◽  
pp. 591-600 ◽  
Author(s):  
ZONG-HONG ZHU
Keyword(s):  
Dark Energy ◽  
Gravitational Lensing ◽  
Cosmological Models ◽  
Distance Measures ◽  
Energy Component ◽  
Dark Energy Component ◽  
Image Separation ◽  
Cosmological Tests ◽  
Age Of The Universe ◽  
The Universe

Various astronomical observations have been consistently making a strong case for the existence of a component of dark energy with negative pressure in the universe. It is now necessary to take the dark energy component(s) into account in gravitational lensing statistics and other cosmological tests. By using the comoving distance we derive analytic but simple expressions for the optical depth of multiple image, the expected value of image separation and the probability distribution of image separation caused by an assemble of singular isothermal spheres in general FRW cosmological models with dark energy component(s). We also present the kinematical and dynamical properties of these kinds of cosmological models and calculate the age of the universe and the distance measures, which are often used in classical cosmological tests. In some cases we are able to give formulae that are simpler than those found elsewhere in the literature, which could make the cosmological tests for dark energy component(s) more convenient.

Dark energy on firmer footing

Nature ◽  
2010 ◽  
Author(s):  
Eugenie Samuel Reich
Keyword(s):  
Dark Energy
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