Cosmology from cosmic shear power spectra with Subaru Hyper Suprime-Cam first-year data

Abstract

We measure cosmic weak lensing shear power spectra with the Subaru Hyper Suprime-Cam (HSC) survey first-year shear catalog covering 137 deg2 of the sky. Thanks to the high effective galaxy number density of ∼17 arcmin−2, even after conservative cuts such as a magnitude cut of i < 24.5 and photometric redshift cut of 0.3 ≤ z ≤ 1.5, we obtain a high-significance measurement of the cosmic shear power spectra in four tomographic redshift bins, achieving a total signal-to-noise ratio of 16 in the multipole range 300 ≤ ℓ ≤ 1900. We carefully account for various uncertainties in our analysis including the intrinsic alignment of galaxies, scatters and biases in photometric redshifts, residual uncertainties in the shear measurement, and modeling of the matter power spectrum. The accuracy of our power spectrum measurement method as well as our analytic model of the covariance matrix are tested against realistic mock shear catalogs. For a flat Λ cold dark matter model, we find $S\,_{8}\equiv \sigma _8(\Omega _{\rm m}/0.3)^\alpha =0.800^{+0.029}_{-0.028}$ for α = 0.45 ($S\,_8=0.780^{+0.030}_{-0.033}$ for α = 0.5) from our HSC tomographic cosmic shear analysis alone. In comparison with Planck cosmic microwave background constraints, our results prefer slightly lower values of S8, although metrics such as the Bayesian evidence ratio test do not show significant evidence for discordance between these results. We study the effect of possible additional systematic errors that are unaccounted for in our fiducial cosmic shear analysis, and find that they can shift the best-fit values of S8 by up to ∼0.6 σ in both directions. The full HSC survey data will contain several times more area, and will lead to significantly improved cosmological constraints.

Baryonic effects for weak lensing. Part I. Power spectrum and covariance matrix

“…The results presented in the left panel of Fig. 10 retrospectively validate the assumptions made in weak-lensing analysis by KiDS [37], DES [38], and HSC [39], where parametrised baryonic suppression functions were multiplied to the power spectrum without considering any cosmology dependence. Furthermore, the results show that ignoring cosmology dependence of baryonic effects also consist of an acceptable strategy for for future, stage-IV weak lensing surveys.…”

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

“…Since HSC can detect faint galaxies, the resultant PDF has a tail at high redshifts. As a fiducial model, we employ the stacked PDF estimated with Ephor AB code by reweighting the PDF obtained from the COSMOS 30-band observation catalog (Ilbert et al 2009;Laigle et al 2016) so that the distributions of magnitudes for five bands of HSC should match with that of galaxies used in the analysis (for details, see Section 5.2 of Hikage et al 2019). We confirm that the different algorithms give consistent results within a few per-cent for calculations of cross-correlations (see Appendix A).…”

“…In order to confirm the convergence of obtained chains, we compute Gelman-Rubin statistic R for all parameters and run the analysis until the condition R − 1 < 0.01 is reached. For priors from HSC S16A cosmic 6 Though neutrinos are assumed to be massless in the fiducial analysis of Hikage et al (2019), we use another chain, where the sum of neutrinos is set to be 0.06 eV.…”

The accuracy of weak lensing simulations

“…This gravitational lensing effect is commonly referred to as weak lensing or cosmic shear (see, e.g., Bartelmann & Schneider 2001; Kilbinger stefan.hilbert@tum.de 2015, for reviews), and it carries information about both the space-time geometry and the large-scale matter distribution of the Universe. Cosmic shear observations therefore prove extremely useful in tests of cosmological models and constraints on cosmological parameters, as the analyses of the Kilo Degree Survey (KiDS, Hildebrandt et al 2017), the Dark Energy Survey (DES, Abbott et al 2018), and the Subaru Hyper Suprime-Cam (HSC) survey (Hikage et al 2019) have recently demonstrated.…”