HSC Year 1 cosmology results with the minimal bias method: HSC ×bOSS galaxy-galaxy weak lensing and BOSS galaxy clustering

We present cosmological parameter constraints from a blinded joint analysis of galaxy-galaxy weak lensing, Δς(R), and the projected correlation function, wp(R), measured from the first-year HSC (HSC-Y1) data and SDSS spectroscopic galaxies over 0.15<z<0.7. We use luminosity-limited samples as lens samples for Δς and as large-scale structure tracers for wp in three redshift bins, and use the HSC-Y1 galaxy catalog to define a secure sample of source galaxies at zph>0.75 for the Δς measurements, selected based on their photometric redshifts. As a theoretical template, we use the "minimal bias"model for the cosmological clustering observables for the flat ΛCDM cosmological model. We compare the model predictions with the measurements in each redshift bin on large scales, R>12 and 8h-1 Mpc for Δς(R) and wp(R), respectively, where the perturbation-theory-inspired model is valid. As part of our model, we account for the effect of lensing magnification bias on the Δς measurements. When we employ weak priors on cosmological parameters, without cosmic microwave background (CMB) information, we find S8=0.936-0.086+0.092, σ8=0.85-0.11+0.16, and ωm=0.283-0.035+0.12 (mode and 68% credible interval) for the flat ΛCDM model. Although the central value of S8 appears to be larger than those inferred from other cosmological experiments, we find that the difference is consistent with expected differences due to sample variance, and our results are consistent with the other results to within the statistical uncertainties. When combined with the Planck 2018 likelihood for the primary CMB anisotropy information (TT,TE,EE+lowE), we find S8=0.817-0.021+0.022, σ8=0.892-0.056+0.051, ωm=0.246-0.035+0.045, and the equation-of-state parameter of dark energy, wde=-1.28-0.19+0.20 for the flat wCDM model, which is consistent with the flat ΛCDM model to within the error bars.