Hyper SuprimeCam Year 3 Results: Cosmology from Cosmic Shear Power Spectra
Abstract
We measure weak lensing cosmic shear power spectra from the threeyear galaxy shear catalog of the Hyper SuprimeCam (HSC) Subaru Strategic Program imaging survey. The shear catalog covers $416 \ \mathrm{deg}^2$ of the northern sky, with a mean $i$band seeing of 0.59 arcsec and an effective galaxy number density of 15 $\mathrm{arcmin}^{2}$ within our adopted redshift range. With an $i$band magnitude limit of 24.5 mag, and four tomographic redshift bins spanning $0.3 \leq z_{\mathrm{ph}} \leq 1.5$ based on photometric redshifts, we obtain a highsignificance measurement of the cosmic shear power spectra, with a signaltonoise ratio of approximately 26.4 in the multipole range $300<\ell<1800$. The accuracy of our power spectrum measurement is tested against realistic mock shear catalogs, and we use these catalogs to get a reliable measurement of the covariance of the power spectrum measurements. We use a robust blinding procedure to avoid confirmation bias, and model various uncertainties and sources of bias in our analysis, including point spread function systematics, redshift distribution uncertainties, the intrinsic alignment of galaxies and the modeling of the matter power spectrum. For a flat $\Lambda$CDM model, we find $S_8 \equiv \sigma_8 (\Omega_m/0.3)^{0.5} =0.776^{+0.032}_{0.033}$, which is in excellent agreement with the constraints from the other HSC Year 3 cosmology analyses, as well as those from a number of other cosmic shear experiments. This result implies a $\sim$$2\sigma$level tension with the Planck 2018 cosmology. We study the effect that various systematic errors and modeling choices could have on this value, and find that they can shift the bestfit value of $S_8$ by no more than $\sim$$0.5\sigma$, indicating that our result is robust to such systematics.
 Publication:

arXiv eprints
 Pub Date:
 April 2023
 DOI:
 10.48550/arXiv.2304.00701
 arXiv:
 arXiv:2304.00701
 Bibcode:
 2023arXiv230400701D
 Keywords:

 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 35 pages, 18 figures, 6 tables, for coordinated submission to PRD with other HSC Y3 weak lensing cosmology papers  see https://hscrelease.mtk.nao.ac.jp/doc/index.php/wly3/