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 the lowest to highest 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 ^ { \prime } < \theta < 56 ^ { \prime } for \xi _ { + } and 28 ^ { \prime } < \theta < 178 ^ { \prime } 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 \Lambda cold dark matter model , we find S _ { 8 } \equiv \sigma _ { 8 } \sqrt { \Omega _ { m } / 0.3 } = 0.804 _ { -0.029 } ^ { +0.032 } , and \Omega _ { 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 .