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Related papers: The role of Lambda in the cosmological lens equati…

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We investigate some properties of flat cosmological models with a $\Lambda$ term that decreases with time as $\Lambda \propto a^{-m}$ (a is the scale factor and m is a parameter $0\leq m < 3$). The models are equivalent to standard…

Astrophysics · Physics 2009-10-30 V. Silveira , I. Waga

The standard $\Lambda$CDM cosmological model informed by cosmic microwave background (CMB) anisotropies makes a precise prediction for the growth of matter density fluctuations over cosmic time on linear scales. A variety of cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-14 Mathew S. Madhavacheril

It is shown that the cosmological relativity theory prdicts the value Lambda = 1.934 x 10^-35 s^-2 for the cosmological constant. This value of Lambda is in exellent agreement with the measurements recently obtained by the High-Z Supernova…

Astrophysics · Physics 2007-05-23 Moshe Carmeli , Tanya Kuzmenko

Time delays are a key observable in strong gravitational lensing systems. Their theoretical expression is usually written as a sum of a geometrical delay and a Shapiro delay, with cosmology entering through angular diameter distances and a…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-19 Luca Teodori , Kfir Blum , Zhaoyu Bai

S. Weinberg pointed out a way to introduce a cosmological term by modifying the theory of gravity. This modification would be justified if the Einstein equations with the cosmological term could be obtained in the classical limit of some…

General Relativity and Quantum Cosmology · Physics 2011-04-15 T. P. Shestakova

In cosmology, the cosmic curvature $K$ and the cosmological constant $\Lambda$ are two important parameters, and the values have strong influence on the behavior of the universe. In the context of normal cosmology, under the ordinary…

General Relativity and Quantum Cosmology · Physics 2017-08-11 Ying-Qiu Gu

In models with a cosmological constant, a significant component of the large scale cosmic microwave background (CMB) anisotropy is produced at rather low redshifts, z < 1. In these models, the gravitational potential perturbations begin to…

Astrophysics · Physics 2009-07-09 Robert G. Crittenden , Neil Turok

We investigate the cosmological test recently proposed by B. Fort, Y. Mellier and M. Dantel-Fort (FMD), where the observed location of the critical line in gravitational lensing is used to determine the cosmological parameters, $\Omega$ and…

Astrophysics · Physics 2009-10-28 Hideki Asada

Cosmic microwave background lensing has become a new cosmological probe, carrying rich information on the matter power spectrum and distances over the redshift range $z\approx1$-4. We investigate the role of scale dependent new physics,…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-03 Alireza Hojjati , Eric V. Linder

Doppler lensing is the apparent change in object size and magnitude due to peculiar velocities. Objects falling into an overdensity appear larger on its near side, and smaller on its far side, than typical objects at the same redshifts.…

Cosmology and Nongalactic Astrophysics · Physics 2014-12-03 David J. Bacon , Sambatra Andrianomena , Chris Clarkson , Krzysztof Bolejko , Roy Maartens

The cosmological constant, i.e., the energy density stored in the true vacuum state of all existing fields in the Universe, is the simplest and the most natural possibility to describe the current cosmic acceleration. However, despite its…

Astrophysics · Physics 2008-11-26 S. Carneiro , M. A. Dantas , C. Pigozzo , J. S. Alcaniz

Starting from a recently proposed framework for the evaluation of the cosmological averages, we evaluate the higher-order moments for the distribution of a given observable. Then, we explicitly discuss the case of the Hubble-Lema\^itre…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-28 Tiziano Schiavone , Enea Di Dio , Giuseppe Fanizza

In this work, we consider the effect of the cosmological constant on galactic halo size. As a model, we study the general relativistic derivation of orbits in the Schwarzschild-de Sitter metric. We find that there exists a length scale…

General Relativity and Quantum Cosmology · Physics 2018-04-25 Ekapob Kulchoakrungsun , Adrian Lam , David A. Lowe

We propose cosmological redshift-space distortion of correlation functions of galaxies and quasars as a probe of both the density parameter $\Omega_0$ and the cosmological constant $\lambda_0$. In particular, we show that redshift-space…

Astrophysics · Physics 2009-10-28 Takahiko Matsubara , Yasushi Suto

We reanalyse optical gravitational lens surveys from the literature in order to determine relative probabilities in the $\lambda_{0}$-$\Omega_{0}$ plane, using a softened singular isothermal sphere lens model. In addition, we examine a…

Astrophysics · Physics 2007-05-23 Ralf Quast , Phillip Helbig

We present a systematic investigation of the cosmological constant effects in compact stars interiors in the framework of Einstein's gravity. Consideration of a cosmological constant $\Lambda$ in compact stars is motivated by the mechanism…

High Energy Astrophysical Phenomena · Physics 2019-02-05 Noshad Khosravi Largani , David E. Alvarez-Castillo

Of the contributions to the cosmological constant, zero-point energy and self energy contributions scale as $\Lambda^4$ where $\Lambda$ is an ultraviolet cutoff used to regulate the calculations. I show that such contributions vanish when…

High Energy Physics - Theory · Physics 2021-08-18 John F. Donoghue

In this paper a new theory of Dark Matter is proposed. Experimental analysis of several Galaxies show how the non-gravitational contribution to galactic Velocity Rotation Curves can be interpreted as that due to the Cosmological Constant…

Astrophysics · Physics 2007-05-23 G. V. Kraniotis , S. B. Whitehouse

Physics invites the idea that space contains energy whose gravitational effect approximates that of Einstein's cosmological constant, Lambda; nowadays the concept is termed dark energy or quintessence. Physics also suggests the dark energy…

Astrophysics · Physics 2008-11-26 P. J. E. Peebles , Bharat Ratra

The case for a flat Cold Dark Matter model with a positive cosmological constant $\Lambda$ has been recently strongly advocated by some theoreticians. In this paper we give the observers point of view to the light of the most recent…

Astrophysics · Physics 2007-05-23 B. Fort , Y. Mellier
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