Evidence for the Cross-correlation between Cosmic Microwave Background Polarization Lensing from POLARBEAR and Cosmic Shear from Subaru Hyper Suprime-Cam


Abstract in English

We present the first measurement of cross-correlation between the lensing potential, reconstructed from cosmic microwave background (CMB) {it polarization} data, and the cosmic shear field from galaxy shapes. This measurement is made using data from the POLARBEAR CMB experiment and the Subaru Hyper Suprime-Cam (HSC) survey. By analyzing an 11~deg$^2$ overlapping region, we reject the null hypothesis at 3.5$sigma$ and constrain the amplitude of the {bf cross-spectrum} to $widehat{A}_{rm lens}=1.70pm 0.48$, where $widehat{A}_{rm lens}$ is the amplitude normalized with respect to the Planck~2018{} prediction, based on the flat $Lambda$ cold dark matter cosmology. The first measurement of this {bf cross-spectrum} without relying on CMB temperature measurements is possible due to the deep POLARBEAR map with a noise level of ${sim}$6,$mu$K-arcmin, as well as the deep HSC data with a high galaxy number density of $n_g=23,{rm arcmin^{-2}}$. We present a detailed study of the systematics budget to show that residual systematics in our results are negligibly small, which demonstrates the future potential of this cross-correlation technique.

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