scholarly journals Constraining dark energy evolution with gravitational lensing by large scale structures

2004 ◽  
Vol 70 (12) ◽  
Author(s):  
Karim Benabed ◽  
Ludovic Van Waerbeke
Keyword(s):  
Dark Energy ◽  
Gravitational Lensing ◽  
Large Scale ◽  
Energy Evolution ◽  
Large Scale Structures ◽  
Scale Structures

scholarly journals Association Of Distant Radio Sources And Foreground Galaxies

1996 ◽  
Vol 173 ◽  
pp. 83-88
Author(s):  
E. Martínez-González ◽  
N. Benítez
Keyword(s):  
Gravitational Lensing ◽  
Large Scale ◽  
Radio Sources ◽  
Weak Gravitational Lensing ◽  
Large Scale Structures ◽  
Scale Structures ◽  
Red Galaxies ◽  
Intermediate Redshifts

A statistically significant (99.1%) excess of red galaxies from the APM Sky Catalogue is found around a sample of z ∼ 1 1Jy radio sources. The most plausible explanation for this result seems to be the magnification bias caused by the weak gravitational lensing of large scale structures at intermediate redshifts.

scholarly journals Large-scale structure probes of modified gravity

2018 ◽  
Vol 27 (15) ◽  
pp. 1848005 ◽  
Author(s):  
Catherine Heymans ◽  
Gong-Bo Zhao
Keyword(s):  
Gravitational Lensing ◽  
Modified Gravity ◽  
Large Scale ◽  
Information Gain ◽  
Einstein Gravity ◽  
Large Scale Structures ◽  
Modified Gravity Theories ◽  
Scale Structures ◽  
The Impact ◽  
The Universe

Observations of the evolution of large-scale structures in the Universe provides unique tools to confront Einstein’s theory of General Relativity on cosmological scales. We review weak gravitational lensing and galaxy clustering studies, discussing how these can be used in combination in order to constrain a range of different modified gravity theories. We argue that in order to maximise the future information gain from these probes, theoretical effort will be required in order to model the impact of beyond-Einstein gravity in the nonlinear regime of structure formation.

scholarly journals Pushing the Frontiers: uncovering the earliest galaxies in the Hubble Frontier Fields

2015 ◽  
Vol 11 (A29B) ◽  
pp. 812-815
Author(s):  
Rachael C. Livermore
Keyword(s):  
Gravitational Lensing ◽  
Wavelet Decomposition ◽  
Luminosity Function ◽  
Large Scale ◽  
Hubble Space Telescope ◽  
High Background ◽  
Large Scale Structures ◽  
Effective Depth ◽  
Scale Structures ◽  
Intracluster Light

AbstractWith the combination of deep Hubble Space Telescope imaging and magnification due to gravitational lensing, the Hubble Frontier Fields program offers an unprecedented opportunity to study the faint end of the luminosity function at the highest redshifts. Unfortunately, the region of the field that benefits most from this magnification (the immediate vicinity of the critical line) suffers from a high abundance of bright foreground galaxies and high background due to intracluster light. To overcome these difficulties, some method of modelling and subtracting the foreground light is required. Here, I present results using wavelet decomposition to subtract large-scale structures in the clusters, which significantly increases the effective depth of the images, and crucially opens up the most magnified regions of the clusters.

scholarly journals Probing the dark matter density evolution law with large scale structures

2021 ◽  
Vol 81 (7) ◽  
Author(s):  
Kamal Bora ◽  
R. F. L. Holanda ◽  
Shantanu Desai
Keyword(s):  
Dark Matter ◽  
Gravitational Lensing ◽  
Large Scale ◽  
Galaxy Cluster ◽  
Matter Density ◽  
Evolution Law ◽  
Large Scale Structures ◽  
Dark Matter Density ◽  
Scale Structures ◽  
Rule Out

AbstractWe propose a new method to explore a possible departure from the standard time evolution law for the dark matter density. We looked for a violation of this law by using a deformed evolution law, given by $$\rho _c(z) \propto (1+z)^{3+\epsilon }$$ ρ c ( z ) ∝ ( 1 + z ) 3 + ϵ , and then constrain $$\epsilon $$ ϵ . The dataset used for this purpose consists of Strong Gravitational Lensing data obtained from SLOAN Lens ACS, BOSS Emission-line Lens Survey, Strong Legacy Survey SL2S, and SLACS; along with galaxy cluster X-ray gas mass fraction measurements obtained using the Chandra Telescope. Our analyses show that $$\epsilon $$ ϵ is consistent with zero within 1 $$\sigma $$ σ c.l., but the current dataset cannot rule out with high confidence level interacting models of dark matter and dark energy.

AN UPPER LIMIT TO THE DENSITY INHOMOGENEITY IN THE UNIVERSE

1986 ◽  
Vol 01 (02) ◽  
pp. 87-93 ◽  
Author(s):  
LI-ZHI FANG ◽  
YAO-QUAN CHU ◽  
XING-FEN ZHU
Keyword(s):  
Gravitational Lensing ◽  
Density Fluctuation ◽  
Large Scale ◽  
Density Inhomogeneity ◽  
Large Scale Structures ◽  
Upper Limit ◽  
Luminous Matter ◽  
Scale Structures ◽  
Lensing Effect ◽  
The Universe

An upper limit to the amplitude of the overall density fluctuation has been found by means of the gravitational lensing effect of the density inhomogeneity on luminosities of quasars with larger redshifts. The observed differences of luminosities of quasars located at different directions are partially given by the lensing effect; therefore, a useful upper limit to the inhomogeneity can be derived if the luminosity distribution of quasars is uniform enough. We obtain this for the case of Ω=1 universe. The overall matter seems to be less clustered than the luminous matter by a factor of three. It may not be favoured for the biased dark matter scenario for the formation of large scale structures, in the universe.

Some comments about observations and image processing of comet 29P/Schwassmann-Wachmann 1

1999 ◽  
Vol 173 ◽  
pp. 243-248
Author(s):  
D. Kubáček ◽  
A. Galád ◽  
A. Pravda
Keyword(s):  
Image Processing ◽  
Large Scale ◽  
Harvard College ◽  
Oak Ridge ◽  
Large Scale Structures ◽  
Short Period Comet ◽  
Short Period ◽  
Scale Structures ◽  
Harvard College Observatory ◽  
Period Comet

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.

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