Dark matter maps reveal cosmic scaffolding

Massey, Richard; Rhodes, Jason; Ellis, Richard S.; Scoville, N.; Leauthaud, Alexie; Finoguenov, A.; Capak, P.; Bacon, David; Aussel, H.; Kneib, Jean-Paul; Koekemoer, Anton M.; McCracken, H. J.; Mobasher, Bahram; Pires, S.; Réfrégier, Alexandre; Sasaki, S.; Starck, Jean-Luc; Taniguchi, Y.; Taylor, Andy; Taylor, James E.

doi:10.1038/nature05497

Cited by 345 publications

(297 citation statements)

References 20 publications

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“…Measurements of cosmic shear help us to constrain the properties of the cosmic matter distribution (e.g. Semboloni et al 2006;Hoekstra et al 2006;Simon et al 2007;Benjamin et al 2007;Massey et al 2007b;Fu et al 2008), the growth of structure (e.g. Bacon et al 2005;Massey et al 2007c), and the nature of the dark energy (e.g.…”

Section: Introductionmentioning

confidence: 99%

Ray-tracing through the Millennium Simulation: Born corrections and lens-lens coupling in cosmic shear and galaxy-galaxy lensing

Hilbert

Hartlap²,

White

et al. 2009

A&A

318

470

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Context. Weak-lensing surveys need accurate theoretical predictions for interpretation of their results and cosmological-parameter estimation. Aims. We study the accuracy of various approximations to cosmic shear and weak galaxy-galaxy lensing and investigate effects of Born corrections and lens-lens coupling. Methods. We use ray-tracing through the Millennium Simulation, a large N-body simulation of cosmic structure formation, to calculate various cosmic-shear and galaxy-galaxy-lensing statistics. We compare the results from ray-tracing to semi-analytic predictions. Results. (i) We confirm that the first-order approximation (i.e. neglecting lensing effects beyond first order in density fluctuations) provides an excellent fit to cosmic-shear power spectra as long as the actual matter power spectrum is used as input. Common fitting formulae, however, strongly underestimate the cosmic-shear power spectra (by >30% on scales > 10 000). Halo models provide a better fit to cosmic shear-power spectra, but there are still noticeable deviations (∼10%). (ii) Cosmic-shear B-modes, which are induced by Born corrections and lens-lens coupling, are at least three orders of magnitude smaller than cosmic-shear E-modes. Semianalytic extensions to the first-order approximation predict the right order of magnitude for the B-mode. Compared to the ray-tracing results, however, the semi-analytic predictions may differ by a factor two on small scales and also show a different scale dependence. (iii) The first-order approximation may under-or overestimate the galaxy-galaxy-lensing shear signal by several percent due to the neglect of magnification bias, which may lead to a correlation between the shear and the observed number density of lenses. Conclusions. (i) Current semi-analytic models need to be improved in order to match the degree of statistical accuracy expected for future weak-lensing surveys. (ii) Shear B-modes induced by corrections to the first-order approximation are not important for future cosmic-shear surveys. (iii) Magnification bias can be important for galaxy-galaxy-lensing surveys.

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Section: Introductionmentioning

confidence: 99%

Ray-tracing through the Millennium Simulation: Born corrections and lens-lens coupling in cosmic shear and galaxy-galaxy lensing

Hilbert

Hartlap²,

White

et al. 2009

A&A

318

470

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show abstract

“…Böhringer et al 2000;Finoguenov et al 2007a;Vikhlinin et al 2009), observation of weak-lensing distortions of background galaxies (e.g. Marian & Bernstein 2006;Gavazzi & Soucail 2007;Massey et al 2007;Bergé et al 2008).…”

Section: Introductionmentioning

confidence: 99%

SARCS strong-lensing galaxy groups

Foëx¹,

Motta²,

Limousin³

et al. 2013

A&A

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We present the weak-lensing and optical analysis of the SL2S-ARCS (SARCS) sample of strong-lensing candidates. The sample is based on the Strong Lensing Legacy Survey (SL2S), a systematic search of strong-lensing systems in the photometric CanadaFrance-Hawaii Telescope Legacy Survey (CFHTLS). The SARCS sample focusses on arc-like features and is designed to contain mostly galaxy groups. We briefly present the weak-lensing methodology that we used to estimate the mass of the SARCS objects. Among 126 candidates, we obtained a weak-lensing detection (at the 1σ level) for 89 objects with velocity dispersions of the singular isothermal sphere mass model (SIS) ranging from σ SIS ∼ 350 km s −1 to ∼1000 km s −1 with an average value of σ SIS ∼ 600 km s −1 , corresponding to a rich galaxy group (or poor cluster). From the galaxies belonging to the bright end of the group's red sequence (M i < −21), we derived the optical properties of the SARCS candidates. We obtained typical richnesses of N ∼ 5−15 galaxies and optical luminosities of L ∼ 0.5−1.5 × 10 12 L (within a radius of 0.5 Mpc). We used these galaxies to compute luminosity density maps, from which a morphological classification reveals that a large fraction of the sample (∼45%) are groups with a complex light distribution, either elliptical or multi-modal, suggesting that these objects are dynamically young structures. We finally combined the lensing and optical analyses to define a sample of the 80 most secure group candidates, i.e. weak-lensing detection and over-density at the lens position in the luminosity map, to remove false detections and galaxy-scale systems from the initial sample. We use this reduced sample to probe the optical scaling relations in combination with a sample of massive galaxy clusters. We detect the expected correlations over the probed range in mass with a typical scatter of ∼25% in σ SIS at a given richness or luminosity, making these scaling laws interesting mass proxies.

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“…Consequently, using only two-point statistics to place constraints on the cosmological model provides limited insight. Stronger constraints can be obtained using 3D weak lensing maps (Bernardeau et al 1997;Pen et al 2003;Massey et al 2007). An alternative procedure is to consider higher-order statistics of the weak lensing shear field enabling a characterization of the non-Gaussian nature of the signal (see e.g., Takada & Jain 2003;Jarvis et al 2004;Hamana et al 2004;Donoho & Jin 2004).…”

Section: Introductionmentioning

confidence: 99%

Cosmological model discrimination with weak lensing

Pires

Starck

Amara

et al. 2009

A&A

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Weak gravitational lensing provides a unique way of mapping directly the dark matter in the Universe. The majority of lensing analyses use the two-point statistics of the cosmic shear field to constrain the cosmological model, a method that is affected by degeneracies, such as that between σ 8 and Ω m which are respectively the rms of the mass fluctuations on a scale of 8 Mpc/h and the matter density parameter, both at z = 0. However, the two-point statistics only measure the Gaussian properties of the field, and the weak lensing field is non-Gaussian. It has been shown that the estimation of non-Gaussian statistics for weak lensing data can improve the constraints on cosmological parameters. In this paper, we systematically compare a wide range of non-Gaussian estimators to determine which one provides tighter constraints on the cosmological parameters. These statistical methods include skewness, kurtosis, and the higher criticism test, in several sparse representations such as wavelet and curvelet; as well as the bispectrum, peak counting, and a newly introduced statistic called wavelet peak counting (WPC). Comparisons based on sparse representations indicate that the wavelet transform is the most sensitive to non-Gaussian cosmological structures. It also appears that the most helpful statistic for non-Gaussian characterization in weak lensing mass maps is the WPC. Finally, we show that the σ 8 -Ω m degeneracy could be even better broken if the WPC estimation is performed on weak lensing mass maps filtered by the wavelet method, MRLens.

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Dark matter maps reveal cosmic scaffolding

Cited by 345 publications

References 20 publications

Ray-tracing through the Millennium Simulation: Born corrections and lens-lens coupling in cosmic shear and galaxy-galaxy lensing

Ray-tracing through the Millennium Simulation: Born corrections and lens-lens coupling in cosmic shear and galaxy-galaxy lensing

SARCS strong-lensing galaxy groups

Cosmological model discrimination with weak lensing

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