The Shear Testing Programme 2: Factors affecting high-precision weak-lensing analyses

Massey, Richard; Heymans, Catherine; Bergé, Joël; Bernstein, G. M.; Bridle, Sarah; Clowe, Douglas; Dahle, H.; Ellis, Richard S.; Erben, T.; Hetterscheidt, M.; High, F. W.; Hirata, Christopher M.; Hoekstra, Henk; Hudelot, P.; Jarvis, Mike; Johnston, David; Kuijken, Konrad; Margoniner, V. E.; Mandelbaum, Rachel; Mellier, Y.; Nakajima, Reiko; Paulin-Henriksson, S.; Peeples, Molly S.; Roat, Chris; Réfrégier, Alexandre; Rhodes, Jason; Schrabback, T.; Schirmer, M.; Seljak, Uroš; Semboloni, Elisabetta; Waerbeke, Ludovic Van

doi:10.1111/j.1365-2966.2006.11315.x

Cited by 351 publications

(266 citation statements)

References 69 publications

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“…The various shape measurement algorithms have been tested and compared in blind simulations, such as the Shear Testing Program (STEP1/STEP2; Heymans et al 2006;Massey et al 2007a), GREAT08 , and GREAT10 (Kitching et al, 2010). In most of these cases, the objective is to minimize both the shear calibration error m (i.e.…”

Section: Measuring Shearsmentioning

confidence: 99%

Observational probes of cosmic acceleration

et al. 2013

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The accelerating expansion of the universe is the most surprising cosmological discovery in many decades, implying that the universe is dominated by some form of "dark energy" with exotic physical properties, or that Einstein's theory of gravity breaks down on cosmological scales. The profound implications of cosmic acceleration have inspired ambitious efforts to understand its origin, with experiments that aim to measure the history of expansion and growth of structure with percent-level precision or higher. We review in detail the four most well established methods for making such measurements: Type Ia supernovae, baryon acoustic oscillations (BAO), weak gravitational lensing, and the abundance of galaxy clusters. We pay particular attention to the systematic uncertainties in these techniques and to strategies for controlling them at the level needed to exploit "Stage IV" dark energy facilities such as BigBOSS, LSST, Euclid, and WFIRST. We briefly review a number of other approaches including redshift-space distortions, the Alcock-Paczynski effect, and direct measurements of the Hubble constant H 0 . We present extensive forecasts for constraints on the dark energy equation of state and parameterized deviations from General Relativity, achievable with Stage III and Stage IV experimental programs that incorporate supernovae, BAO, weak lensing, and cosmic microwave background data. We also show the level of precision required for clusters or other methods to provide constraints competitive with those of these fiducial programs. We emphasize the value of a balanced program that employs several of the most powerful methods in combination, both to cross-check systematic uncertainties and to take advantage of complementary information. Surveys to probe cosmic acceleration produce data sets that support a wide range of scientific investigations, and they continue the longstanding astronomical tradition of mapping the universe in ever greater detail over ever larger scales.

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Section: Measuring Shearsmentioning

confidence: 99%

Observational probes of cosmic acceleration

et al. 2013

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“…The shear calibration error of the shear estimation methods that we use for the SDSS were tested as part of the Shear TEsting Program II (STEP2 ; Massey et al (2007)) and found to be less than a percent (for the RM method in STEP2). However, we allow for a 3% error in shear calibration since the STEP simulation error may not represent the full calibration error when these methods are applied to real data -e.g., the PSF modeling of SDSS was not tested in STEP.…”

Section: Systematic Errorsmentioning

confidence: 99%

Cross-correlation Weak Lensing of SDSS galaxy Clusters II: Cluster Density Profiles and the Mass--Richness Relation

Johnston¹,

Sheldon²,

Rozo³

et al. 2007

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We interpret and model the statistical weak lensing measurements around 130,000 groups and clusters of galaxies in the Sloan Digital Sky Survey presented by Sheldon et al. (2007). We present non-parametric inversions of the 2D shear profiles to the mean 3D cluster density and mass profiles in bins of both optical richness and cluster i-band luminosity. Since the mean cluster density profile is proportional to the cluster-mass correlation function, the mean profile is spherically symmetric by the assumptions of large-scale homogeneity and isotropy. We correct the inferred 3D profiles for systematic effects, including non-linear shear and the fact that cluster halos are not all precisely centered on their brightest galaxies. We also model the measured cluster shear profile as a sum of contributions from the brightest central galaxy, the cluster dark matter halo, and neighboring halos. We infer the relations between mean cluster virial mass and optical richness and luminosity over two orders of magnitude in cluster mass; the virial mass at fixed richness or luminosity is determined with a precision of ∼ 13% including both statistical and systematic errors. We also constrain the halo concentration parameter and halo bias as a function of cluster mass; both are in good agreement with predictions from N-body simulations of LCDM models. The methods employed here will be applicable to deeper, wide-area optical surveys that aim to constrain the nature of the dark energy, such as the Dark Energy Survey, the Large Synoptic Survey Telescope and space-based surveys.

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“…STEP 2 is a project for testing the precision of weaklensing measurements (see Massey et al 2007). It uses several distortions and six PSF patterns for the same source objects and tests the precision of various shear measurement methods, including KSB.…”

Section: Motivation For and Merits Of Using E-holicsmentioning

confidence: 99%

“…In order to test the accuracy of various shear measurement schemes, some testing programs, such as the Shear Testing Programme 1 (STEP 1; Heymans et al 2006), and Shear Testing Programme 2 (STEP 2; Massey et al 2007), have been developed. For example, the results of STEP 2 showed that most of the methods attain the level of a few percent accuracy.…”

Section: Introductionmentioning

confidence: 99%

ELLIPTICALLY WEIGHTED HOLICs FOR WEAK-LENSING SHEAR MEASUREMENT. I. DEFINITIONS AND ISOTROPIC POINT-SPREAD FUNCTION CORRECTION

Okura

Futamase

2011

ApJ

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We develop a new method of estimating gravitational shear by adopting an elliptical weight function to measure background galaxy images. In doing so, we introduce the new concept of "zero plane," which is an imaginary source plane where shapes of all sources are perfect circles, and regard the intrinsic shear as the result of an imaginary lensing distortion. This makes the relation between the observed shear, intrinsic shear, and lensing distortion much simpler, and thus higher-order calculations are easier. The elliptical weight function allows us to measure the multipole moments of the shapes of background galaxies more precisely by weighting brighter parts of the image highly, and to reduce systematic error due to insufficient expansion of the weight function in the original approach of Kaiser et al. (KSB). Point-spread function (PSF) correction in the elliptically weighted higher-order lensing image characteristics (E-HOLICs) method becomes more complicated than in the KSB method. In this paper, we study isotropic PSF correction in detail. By adopting the lensing distortion as the ellipticity of the weight function, we are able to show that the shear estimation in the E-HOLICs method reduces to solve a polynomial in the absolute magnitude of the distortion. We compare the systematic errors between our approach and that of KSB using the Shear Testing Programme 2 simulation. It is confirmed that the KSB method overestimates the input shear for images with large ellipticities, and E-HOLICs correctly estimates the input shear even for such images. Anisotropic PSF correction and analysis of real data will be presented in a forthcoming paper.

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The Shear Testing Programme 2: Factors affecting high-precision weak-lensing analyses

Cited by 351 publications

References 69 publications

Observational probes of cosmic acceleration

Observational probes of cosmic acceleration

Cross-correlation Weak Lensing of SDSS galaxy Clusters II: Cluster Density Profiles and the Mass--Richness Relation

ELLIPTICALLY WEIGHTED HOLICs FOR WEAK-LENSING SHEAR MEASUREMENT. I. DEFINITIONS AND ISOTROPIC POINT-SPREAD FUNCTION CORRECTION

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