scholarly journals Weak Gravitational Lensing of High‐Redshift 21 cm Power Spectra

2006 ◽  
Vol 647 (2) ◽  
pp. 719-736 ◽  
Author(s):  
Kaisey S. Mandel ◽  
Matias Zaldarriaga
Keyword(s):  
Gravitational Lensing ◽  
High Redshift ◽  
Power Spectra ◽  
Weak Gravitational Lensing

scholarly journals Cross-correlation of the thermal Sunyaev–Zel’dovich effect and weak gravitational lensing: Planck and Subaru Hyper Suprime-Cam first-year data

2020 ◽  
Vol 492 (4) ◽  
pp. 4780-4804 ◽  
Author(s):  
Ken Osato ◽  
Masato Shirasaki ◽  
Hironao Miyatake ◽  
Daisuke Nagai ◽  
Naoki Yoshida ◽  
...  
Keyword(s):  
Gravitational Lensing ◽  
Cross Correlation ◽  
High Redshift ◽  
Cosmological Parameters ◽  
First Year ◽  
Weak Gravitational Lensing ◽  
Mass Bias ◽  
Cross Correlation Analysis ◽  
Sunyaev Zel'dovich Effect ◽  
Calibration Techniques

ABSTRACT Cross-correlation analysis of the thermal Sunyaev–Zel’dovich (tSZ) effect and weak gravitational lensing (WL) provides a powerful probe of cosmology and astrophysics of the intracluster medium. We present the measurement of the cross-correlation of tSZ and WL from Planck and Subaru Hyper-Suprime Cam. The combination enables us to study cluster astrophysics at high redshift. We use the tSZ-WL cross-correlation and the tSZ autopower spectrum measurements to place a tight constraint on the hydrostatic mass bias, which is a measure of the degree of non-thermal pressure support in galaxy clusters. With the prior on cosmological parameters derived from the analysis of the cosmic microwave background anisotropies by Planck and taking into account foreground contributions both in the tSZ autopower spectrum and the tSZ-WL cross-correlation, the hydrostatic mass bias is estimated to be $26.9^{+8.9}_{-4.4} {{\ \rm per\ cent}}$ ($68{{\ \rm per\ cent}}$ CL), which is consistent with recent measurements by mass calibration techniques.

scholarly journals XMM-Newton X-ray and HST weak gravitational lensing study of the extremely X-ray luminous galaxy cluster Cl J120958.9+495352 (z = 0.902)

2018 ◽  
Vol 610 ◽  
pp. A71 ◽  
Author(s):  
Sophia Thölken ◽  
Tim Schrabback ◽  
Thomas H. Reiprich ◽  
Lorenzo Lovisari ◽  
Steven W. Allen ◽  
...  
Keyword(s):  
Temperature Profile ◽  
Gravitational Lensing ◽  
Mass Fraction ◽  
High Redshift ◽  
Galaxy Cluster ◽  
Cooling Time ◽  
Weak Lensing ◽  
Imaging Data ◽  
Weak Gravitational Lensing ◽  
X Ray

Context. Observations of relaxed, massive, and distant clusters can provide important tests of standard cosmological models, for example by using the gas mass fraction. To perform this test, the dynamical state of the cluster and its gas properties have to be investigated. X-ray analyses provide one of the best opportunities to access this information and to determine important properties such as temperature profiles, gas mass, and the total X-ray hydrostatic mass. For the last of these, weak gravitational lensing analyses are complementary independent probes that are essential in order to test whether X-ray masses could be biased. Aims. We study the very luminous, high redshift (z = 0.902) galaxy cluster Cl J120958.9+495352 using XMM-Newton data. We measure global cluster properties and study the temperature profile and the cooling time to investigate the dynamical status with respect to the presence of a cool core. We use Hubble Space Telescope (HST) weak lensing data to estimate its total mass and determine the gas mass fraction. Methods. We perform a spectral analysis using an XMM-Newton observation of 15 ks cleaned exposure time. As the treatment of the background is crucial, we use two different approaches to account for the background emission to verify our results. We account for point spread function effects and deproject our results to estimate the gas mass fraction of the cluster. We measure weak lensing galaxy shapes from mosaic HST imaging and select background galaxies photometrically in combination with imaging data from the William Herschel Telescope. Results. The X-ray luminosity of Cl J120958.9+495352 in the 0.1–2.4 keV band estimated from our XMM-Newton data is LX = (13.4−1.0+1.2) × 1044 erg/s and thus it is one of the most X-ray luminous clusters known at similarly high redshift. We find clear indications for the presence of a cool core from the temperature profile and the central cooling time, which is very rare at such high redshifts. Based on the weak lensing analysis, we estimate a cluster mass of M500 / 1014 M⊙ = 4.4−2.0+2.2(star.) ± 0.6(sys.) and a gas mass fraction of fgas,2500 = 0.11−0.03+0.06 in good agreement with previous findings for high redshift and local clusters.

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 Cosmology with weak lensing surveys

2005 ◽  
Vol 363 (1837) ◽  
pp. 2675-2691 ◽  
Author(s):  
Dipak Munshi ◽  
Patrick Valageas
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Gravitational Lensing ◽  
Large Scale ◽  
High Redshift ◽  
Cosmological Parameters ◽  
Power Spectra ◽  
Weak Lensing ◽  
Satellite Mission ◽  
The Universe

Weak gravitational lensing is responsible for the shearing and magnification of the images of high-redshift sources due to the presence of intervening mass. Since the lensing effects arise from deflections of the light rays due to fluctuations of the gravitational potential, they can be directly related to the underlying density field of the large-scale structures. Weak gravitational surveys are complementary to both galaxy surveys and cosmic microwave background observations as they probe unbiased nonlinear matter power spectra at medium redshift. Ongoing CMBR experiments such as WMAP and a future Planck satellite mission will measure the standard cosmological parameters with unprecedented accuracy. The focus of attention will then shift to understanding the nature of dark matter and vacuum energy: several recent studies suggest that lensing is the best method for constraining the dark energy equation of state. During the next 5 year period, ongoing and future weak lensing surveys such as the Joint Dark Energy Mission (JDEM; e.g. SNAP) or the Large-aperture Synoptic Survey Telescope will play a major role in advancing our understanding of the universe in this direction. In this review article, we describe various aspects of probing the matter power spectrum and the bispectrum and other related statistics with weak lensing surveys. This can be used to probe the background dynamics of the universe as well as the nature of dark matter and dark energy.

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+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 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

Current status of weak gravitational lensing

2002 ◽  
Vol 46 (12) ◽  
pp. 767-781 ◽  
Author(s):  
Henk Hoekstra ◽  
H.K.C Yee ◽  
Michael D Gladders
Keyword(s):  
Gravitational Lensing ◽  
Current Status ◽  
Weak Gravitational Lensing
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