Cross-correlation between Subaru Hyper Suprime-Cam Galaxy Weak Lensing and Planck Cosmic Microwave Background Lensing

Cross-correlations between galaxy weak lensing (WL) and cosmic microwave background (CMB) lensing are powerful tools to probe matter fluctuations at intermediate redshifts and to detect residual systematics in either probe. In this paper, we study the cross-correlation of galaxy WL from the Hyper Suprime-Cam Subaru Strategic Program (HSC) first data release and CMB lensing from the final Planck data release, for HSC source galaxies at 0.3 <= z <= 1.5. HSC is the deepest Stage-III galaxy WL survey, and provides a great opportunity to study the high-redshift universe. It also presents new challenges related to its exceptionally high source density, such as source blending. The cross-correlation signal is measured at a significance level of 3.1 sigma. The amplitude of our best-fit model with respect to the best-fit 2018 Planck cosmology is A = 0.81 0.25, consistent with A = 1. Our result is also consistent with previous CMB lensing and galaxy WL cross-correlation studies using different surveys. We perform tests with respect to the WL B-modes, the point-spread-function, photometric redshift errors, and thermal Sunyaev-Zel'dovich leakage, and find no significant evidence of residual systematics.