Cosmological inference from an emulator based halo model. II. Joint analysis of galaxy-galaxy weak lensing and galaxy clustering from HSC-Y1 and SDSS

We present high-fidelity cosmology results from a blinded joint analysis of galaxy-galaxy weak lensing (Δ Σ ) and projected galaxy clustering (w_p) measured from the Hyper Suprime-Cam Year-1 (HSC-Y1) data and spectroscopic Sloan Digital Sky Survey (SDSS) galaxy catalogs in the redshift range 0.15 <z <0.7 . We define luminosity-limited samples of SDSS galaxies to serve as the tracers of w_p in three spectroscopic redshift bins, and as the lens samples for Δ Σ . For the Δ Σ measurements, we select a single sample of 4 ×10⁶ source galaxies over 140 deg² from HSC-Y1 with photometric redshifts (photo z ) greater than 0.75, enabling a better handle of photo-z errors by comparing the Δ Σ amplitudes for the three lens redshift bins. The deep, high-quality HSC-Y1 data enable significant detections of the Δ Σ signals, with integrated signal-to-noise ratio S /N ∼15 in the range 3 ≤R /[h^-1 Mpc ]≤30 for the three lens samples, despite the small area coverage. For cosmological parameter inference, we use an input galaxy-halo connection model built on the DARK EMULATOR package (which uses an ensemble set of high-resolution N -body simulations and enables fast, accurate computation of the clustering observables) with a halo occupation distribution that includes nuisance parameters to marginalize over modeling uncertainties. We model the Δ Σ and w_p measurements on scales from R ≃3 and 2 h^-1 Mpc , respectively, up to 30 h^-1 Mpc (therefore excluding the baryon acoustic oscillations information) assuming a flat Λ CDM cosmology, marginalizing over about 20 nuisance parameters and demonstrating the robustness of our results to them. With various tests using mock catalogs described in Miyatake et al. [preceding paper, Phys. Rev. D 106, 083519 (2022), 10.1103/PhysRevD.106.083519], we show that any bias in the clustering amplitude S₈≡σ₈(Ω_m/0.3 )^0.5 due to uncertainties in the galaxy-halo connection is less than ∼50 % of the statistical uncertainty of S₈, unless the assembly biaseffect is unexpectedly large. Our best-fit models have S₈=0.79 5_-0.042^+0.049 (mode and 68% credible interval) for the flat Λ CDM model; we find tighter constraints on the quantity S₈(α =0.17 )≡σ₈(Ω_m/0.3 )^0.17=0.74 5_-0.031^+0.039 .