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

TL;DR

This study measures the cross-correlation between galaxy weak lensing from the Hyper Suprime-Cam survey and CMB lensing from Planck, confirming consistency with cosmological models and demonstrating the method's robustness against systematics.

Contribution

It presents the first cross-correlation measurement between HSC galaxy weak lensing data and Planck CMB lensing, highlighting the potential for high-redshift universe studies.

Findings

Cross-correlation signal detected at 3.1σ significance.

Best-fit amplitude consistent with Planck cosmology (A=0.81±0.25).

No significant residual systematics found.

Abstract

Cross-correlations between galaxy weak lensing (WL) and Cosmic Microwave Background (CMB) lensing are a powerful tool 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 both a great opportunity to study the high-redshift universe and 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 $A = 0.81\pm 0.25$, 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.