Abstract
We present measurements of cosmic shear two-point correlation functions
(TPCFs) from Hyper Suprime-Cam Subaru Strategic Program (HSC SSP) first-year
data, and derived cosmological constraints based on a blind analysis. The HSC
first-year shape catalog is divided into four tomographic redshift bins ranging
from $z=0.3$ to 1.5 with equal widths of $\Delta z =0.3$. The unweighted galaxy
number densities in each tomographic bin are 5.9, 5.9, 4.3, and 2.4
arcmin$^-2$ from lower to higher redshifts, respectively. We adopt the
standard TPCF estimators, $\xi_\pm$, for our cosmological analysis, given that
we find no evidence of the significant B-mode shear. The TPCFs are detected at
high significance for all ten combinations of auto- and cross-tomographic bins
over a wide angular range, yielding a total signal-to-noise ratio of 19 in the
angular ranges adopted in the cosmological analysis, $7'<þeta<56'$ for
$\xi_+$ and $28'<þeta<178'$ for $\xi_-$. We perform the standard Bayesian
likelihood analysis for cosmological inference from the measured cosmic shear
TPCFs, including contributions from intrinsic alignment of galaxies as well as
systematic effects from PSF model errors, shear calibration uncertainty, and
source redshift distribution errors. We adopt a covariance matrix derived from
realistic mock catalogs constructed from full-sky gravitational lensing
simulations that fully account for survey geometry and measurement noise. For a
flat $Łambda$ cold dark matter model, we find $S_8 \equiv
\sigma_8Ømega_m/0.3=0.804_-0.029^+0.032$, and
$Ømega_m=0.346_-0.100^+0.052$. We carefully check the robustness of the
cosmological results against astrophysical modeling uncertainties and
systematic uncertainties in measurements, and find that none of them has a
significant impact on the cosmological constraints.
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