scholarly journals Probing Dark Energy via Weak Gravitational Lensing with the Supernova Acceleration Probe (SNAP)

2005 ◽  
Author(s):  
J. Albert ◽  
G. Aldering ◽  
S. Allam ◽  
W. Althouse ◽  
R. Amanullah ◽  
...  
Keyword(s):  
Dark Energy ◽  
Gravitational Lensing ◽  
Weak Gravitational Lensing

scholarly journals KiDS+VIKING-450 and DES-Y1 combined: Cosmology with cosmic shear

2020 ◽  
Vol 638 ◽  
pp. L1 ◽  
Author(s):  
S. Joudaki ◽  
H. Hildebrandt ◽  
D. Traykova ◽  
N. E. Chisari ◽  
C. Heymans ◽  
...  
Keyword(s):  
Dark Energy ◽  
Cosmic Microwave Background ◽  
Gravitational Lensing ◽  
Error Model ◽  
Calibration Error ◽  
Microwave Background ◽  
Weak Gravitational Lensing ◽  
Dark Energy Survey ◽  
Cosmic Shear ◽  
Energy Survey

We present a combined tomographic weak gravitational lensing analysis of the Kilo Degree Survey (KV450) and the Dark Energy Survey (DES-Y1). We homogenize the analysis of these two public cosmic shear datasets by adopting consistent priors and modeling of nonlinear scales, and determine new redshift distributions for DES-Y1 based on deep public spectroscopic surveys. Adopting these revised redshifts results in a 0.8σ reduction in the DES-inferred value for S​8, which decreases to a 0.5σ reduction when including a systematic redshift calibration error model from mock DES data based on the MICE2 simulation. The combined KV450+DES-Y1 constraint on S8 = 0.762−0.024+0.025 is in tension with the Planck 2018 constraint from the cosmic microwave background at the level of 2.5σ. This result highlights the importance of developing methods to provide accurate redshift calibration for current and future weak-lensing surveys.

scholarly journals Testing dark energy paradigms with weak gravitational lensing

2012 ◽  
Vol 85 (10) ◽  
Author(s):  
R. Ali Vanderveld ◽  
Michael J. Mortonson ◽  
Wayne Hu ◽  
Tim Eifler
Keyword(s):  
Dark Energy ◽  
Gravitational Lensing ◽  
Weak Gravitational Lensing

scholarly journals Clustering dark energy imprints on cosmological observables of the gravitational field

2020 ◽  
Vol 500 (4) ◽  
pp. 4514-4529
Author(s):  
Farbod Hassani ◽  
Julian Adamek ◽  
Martin Kunz
Keyword(s):  
Dark Energy ◽  
Gravitational Field ◽  
Time Delay ◽  
Gravitational Lensing ◽  
Power Spectra ◽  
Gravitational Redshift ◽  
Weak Gravitational Lensing ◽  
Angular Power Spectrum ◽  
Energy Field ◽  
High Degree

ABSTRACT We study cosmological observables on the past light-cone of a fixed observer in the context of clustering dark energy. We focus on observables that probe the gravitational field directly, namely the integrated Sachs–Wolfe and non-linear Rees–Sciama effect (ISW-RS), weak gravitational lensing, gravitational redshift, and Shapiro time delay. With our purpose-built N-body code ‘k-evolution’ that tracks the coupled evolution of dark matter particles and the dark energy field, we are able to study the regime of low speed of sound cs where dark energy perturbations can become quite large. Using ray tracing, we produce two-dimensional sky maps for each effect and we compute their angular power spectra. It turns out that the ISW-RS signal is the most promising probe to constrain clustering dark energy properties coded in $w-c_\mathrm{ s}^2$, as the linear clustering of dark energy would change the angular power spectrum by ${\sim}30{{\ \rm per\ cent}}$ at low ℓ when comparing two different speeds of sound for dark energy. Weak gravitational lensing, Shapiro time delay, and gravitational redshift are less sensitive probes of clustering dark energy, showing variations of only a few per cent. The effect of dark energy non-linearities in all the power spectra is negligible at low ℓ, but reaches about $2{{\ \rm per\ cent}}$ and $3{{\ \rm per\ cent}}$, respectively, in the convergence and ISW-RS angular power spectra at multipoles of a few hundred when observed at redshift ∼0.85. Future cosmological surveys achieving per cent precision measurements will allow us to probe the clustering of dark energy to a high degree of confidence.

scholarly journals Image Simulations for Strong and Weak Gravitational Lensing

Symmetry ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 494 ◽  
Author(s):  
Andrés A. Plazas
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Systematic Error ◽  
Gravitational Lensing ◽  
Model Development ◽  
Full Potential ◽  
Weak Gravitational Lensing ◽  
General Overview ◽  
Error Characterization ◽  
Image Simulations

Gravitational lensing has been identified as a powerful tool to address fundamental problems in astrophysics at different scales, ranging from exoplanet identification to dark energy and dark matter characterization in cosmology. Image simulations have played a fundamental role in the realization of the full potential of gravitational lensing by providing a means to address needs such as systematic error characterization, pipeline testing, calibration analyses, code validation, and model development. We present a general overview of the generation and applications of image simulations in strong and weak gravitational lensing.

scholarly journals Scale dependence of galaxy biasing investigated by weak gravitational lensing: An assessment using semi-analytic galaxies and simulated lensing data

2018 ◽  
Vol 613 ◽  
pp. A15 ◽  
Author(s):  
Patrick Simon ◽  
Stefan Hilbert
Keyword(s):  
Gravitational Lensing ◽  
Spatial Scales ◽  
Scale Dependence ◽  
Reconstruction Technique ◽  
Weak Gravitational Lensing ◽  
Physical Scale ◽  
The Galaxy ◽  
Galaxy Bias ◽  
The Impact ◽  
Lens Galaxies

Galaxies are biased tracers of the matter density on cosmological scales. For future tests of galaxy models, we refine and assess a method to measure galaxy biasing as a function of physical scalekwith weak gravitational lensing. This method enables us to reconstruct the galaxy bias factorb(k) as well as the galaxy-matter correlationr(k) on spatial scales between 0.01hMpc−1≲k≲ 10hMpc−1for redshift-binned lens galaxies below redshiftz≲ 0.6. In the refinement, we account for an intrinsic alignment of source ellipticities, and we correct for the magnification bias of the lens galaxies, relevant for the galaxy-galaxy lensing signal, to improve the accuracy of the reconstructedr(k). For simulated data, the reconstructions achieve an accuracy of 3–7% (68% confidence level) over the abovek-range for a survey area and a typical depth of contemporary ground-based surveys. Realistically the accuracy is, however, probably reduced to about 10–15%, mainly by systematic uncertainties in the assumed intrinsic source alignment, the fiducial cosmology, and the redshift distributions of lens and source galaxies (in that order). Furthermore, our reconstruction technique employs physical templates forb(k) andr(k) that elucidate the impact of central galaxies and the halo-occupation statistics of satellite galaxies on the scale-dependence of galaxy bias, which we discuss in the paper. In a first demonstration, we apply this method to previous measurements in the Garching-Bonn Deep Survey and give a physical interpretation of the lens population.

scholarly journals KiDS-450: cosmological parameter constraints from tomographic weak gravitational lensing

2016 ◽  
Vol 465 (2) ◽  
pp. 1454-1498 ◽  
Author(s):  
H. Hildebrandt ◽  
M. Viola ◽  
C. Heymans ◽  
S. Joudaki ◽  
K. Kuijken ◽  
...  
Keyword(s):  
Gravitational Lensing ◽  
Cosmological Parameter ◽  
Weak Gravitational Lensing ◽  
Parameter Constraints
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