Survey geometry and the internal consistency of recent cosmic shear measurements

Troxel, M. A.; Krause, E.; Chang, C.; Eifler, T. F.; Friedrich, Oliver; Gruen, D.; MacCrann, N.; Chen, A.; Davis, C.; DeRose, Joseph J.; Dodelson, Scott; Gatti, M.; Hoyle, B.; Huterer, Dragan; Jarvis, Mike; Lacasa, F.; Lemos, Pablo; Peiris, Hiranya V.; Prat, J.; Samuroff, S.; Sánchez, C.; Sheldon, E.; Vielzeuf, P.; Wang, M.; Zuntz, Joe; Lahav, O.; Abdalla, F. B.; Allam, S.; Annis, J.; Ávila, S.; Bertin, E.; Brooks, D.; Burke, D. L.; Rosell, A. Carnero; Kind, M. Carrasco; Carretero, J.; Crocce, M.; Cunha, C. E.; D’Andrea, C. B.; Costa, L. N. da; Vicente, J. De; Diehl, H. T.; Doel, P.; Evrard, A. E.; Flaugher, B.; Fosalba, P.; Frieman, J.; García-Bellido, J.; Gaztañaga, E.; Gerdes, D. W.; Gruendl, R. A.; Gschwend, J.; Gutiérrez, G.; Hartley, W. G.; Hollowood, D. L.; Honscheid, K.; James, D. J.; Kirk, D.; Kuêhn, K.; Kuropatkin, N.; Li, T. S.; Lima, M.; March, M.; Menanteau, F.; Miquel, R.; Mohr, J. J.; Ogando, R. L. C.; Plazas, A. A.; Roodman, A.; Sánchez, E.; Scarpine, V.; Schindler, R. H.; Sevilla-Noarbe, I.; Smith, M.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Thomas, Daniel; Walker, A. R.; Wechsler, Risa H.

doi:10.1093/mnras/sty1889

Cited by 93 publications

(121 citation statements)

References 38 publications

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“…The publicly available covariance that we employ makes idealistic assumptions about the shot noise contribution which leads to an under-prediction of variance on large scales where the survey geometry becomes relevant. This was recently shown to be the reason behind the relatively large χ 2 values found for previous KiDS and DES analyses (Troxel et al 2018b). As the posterior was largely unaffected, we can proceed with the available covariance matrix but have to keep the above limitations in mind when interpreting the goodness of fit.…”

Section: Covariancementioning

confidence: 82%

KiDS + GAMA: constraints on horndeski gravity from combined large-scale structure probes

Mancini

Köhlinger

Joachimi

et al. 2019

Monthly Notices of the Royal Astronomical Society

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We present constraints on Horndeski gravity from a combined analysis of cosmic shear, galaxy-galaxy lensing and galaxy clustering from 450 deg 2 of the Kilo-Degree Survey (KiDS) and the Galaxy And Mass Assembly (GAMA) survey. The Horndeski class of dark energy/modified gravity models includes the majority of universally coupled extensions to ΛCDM with one scalar field in addition to the metric. We study the functions of time that fully describe the evolution of linear perturbations in Horndeski gravity. Our results are compatible throughout with a ΛCDM model. By imposing gravitational wave constraints, we fix the tensor speed excess to zero and consider a subset of models including e.g. quintessence and f (R) theories. Assuming proportionality of the Horndeski functions α B and α M (kinetic braiding and the Planck mass run rate, respectively) to the dark energy density fraction Ω DE (a) = 1 − Ω m (a), we find for the proportionality coefficientsα B = 0.20 +0.20 −0.33 andα M = 0.25 +0.19 −0.29 . Our value of S 8 ≡ σ 8√ Ω m /0.3 is in better agreement with the Planck estimate when measured in the enlarged Horndeski parameter space than in a pure ΛCDM scenario. In our joint three-probe analysis we report a downward shift of the S 8 best fit value from the Planck measurement of ∆S 8 = 0.016 +0.048 −0.046 in Horndeski gravity, compared to ∆S 8 = 0.059 +0.040 −0.039 in ΛCDM. Our constraints are robust to the modelling uncertainty of the non-linear matter power spectrum in Horndeski gravity. Our likelihood code for multi-probe analysis in both ΛCDM and Horndeski gravity is publicly available at https://github.com/alessiospuriomancini/KiDSHorndeski.

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Section: Covariancementioning

confidence: 82%

KiDS + GAMA: constraints on horndeski gravity from combined large-scale structure probes

Mancini

Köhlinger

Joachimi

et al. 2019

Monthly Notices of the Royal Astronomical Society

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“…We extend their method to make it valid for tomographic analyses in Appendix A. A similar investigation of the impact of survey geometry on covariance estimation is found in Troxel et al (2018b). It is worth noting that this study focuses on the case where the shape noise is less important, while Troxel et al (2018b) mainly studied the effect of survey geometry on shape noise covariances.…”

Section: Gaussian Covariancementioning

confidence: 94%

Mock galaxy shape catalogues in the Subaru Hyper Suprime-Cam Survey

Shirasaki

Hamana

Takada

et al. 2019

Monthly Notices of the Royal Astronomical Society

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We use the full-sky ray-tracing weak lensing simulations to generate 2268 mock catalogues for the Subaru Hyper Suprime-Cam (HSC) survey first-year shear catalogue. Our mock catalogues take into account various effects as in the real data: the survey footprints, inhomogeneous angular distribution of source galaxies, statistical uncertainties in photometric redshift (photo-z) estimate, variations in the lensing weight, and the statistical noise in galaxy shape measurements including both intrinsic shapes and the measurement errors. We then utilize our mock catalogues to evaluate statistical uncertainties expected in measurements of cosmic shear twopoint correlations ξ ± with tomographic redshift information for the HSC survey. We develop a quasi-analytical formula for the Gaussian sample variance properly taking into account the number of source pairs in the survey footprints. The standard Gaussian formula significantly overestimates or underestimates the mock results by 50% level. We also show that different photo-z catalogues or the six disconnected fields, rather than a consecutive geometry, cause variations in the covariance by ∼ 5%. The mock catalogues enable us to study the chi-square distribution for ξ ± . We find the wider distribution than that naively expected for the distribution with the degrees-of-freedom of data vector used. Finally, we propose a method to include nonzero multiplicative bias in mock shape catalogue and show the non-zero multiplicative bias can change the effective shape noise in cosmic shear analyses. Our results suggest an importance of estimating an accurate form of the likelihood function (and therefore the covariance) for robust cosmological parameter inference from the precise measurements.

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“…ξ AE . We explore this change and other updates to the KiDS-450 cosmic shear analysis and how they impact comparison with the DES Y1 results shown here in [140]. We enforce our fiducial model choices for intrinsic alignment and baryon scale cuts, in addition to the recommended scale cuts in the original analysis.…”

Section: Comparison To External Measurementsmentioning

confidence: 99%

Dark Energy Survey Year 1 results: Cosmological constraints from cosmic shear

Troxel¹,

MacCrann²,

Zuntz³

et al. 2018

Phys. Rev. D

588

564

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We use 26 × 10 6 galaxies from the Dark Energy Survey (DES) Year 1 shape catalogs over 1321 deg 2 of the sky to produce the most significant measurement of cosmic shear in a galaxy survey to date. We constrain cosmological parameters in both the flat ΛCDM and the wCDM models, while also varying the neutrino mass density. These results are shown to be robust using two independent shape catalogs, two independent photo-z calibration methods, and two independent analysis pipelines in a blind analysis. We find a 3.5% fractional uncertainty on σ 8 ðΩ m =0.3Þ 0.5 ¼ 0.782 −0.39 . We find results that are consistent with previous cosmic shear constraints in σ 8 -Ω m , and we see no evidence for disagreement of our weak lensing data with data from the cosmic microwave background. Finally, we find no evidence preferring a wCDM model allowing w ≠ −1. We expect further significant improvements with subsequent years of DES data, which will more than triple the sky coverage of our shape catalogs and double the effective integrated exposure time per galaxy.

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Survey geometry and the internal consistency of recent cosmic shear measurements

Cited by 93 publications

References 38 publications

KiDS + GAMA: constraints on horndeski gravity from combined large-scale structure probes

KiDS + GAMA: constraints on horndeski gravity from combined large-scale structure probes

Mock galaxy shape catalogues in the Subaru Hyper Suprime-Cam Survey

Dark Energy Survey Year 1 results: Cosmological constraints from cosmic shear

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