DESI-DR1 $3 \times 2$-pt analysis: consistent cosmology across weak lensing surveys

TL;DR

This paper combines galaxy clustering and weak lensing data from multiple surveys to constrain cosmological parameters, achieving consistent results with Planck CMB measurements and introducing a unified analysis pipeline.

Contribution

It presents the first joint $3 imes 2$-point analysis across DESI-DR1, KiDS-1000, DES-Y3, and HSC-Y3, with a new pipeline and covariance modeling.

Findings

Measured $S_8$ values consistent across surveys and with Planck.

Developed an analytical covariance matrix including all cross-probe covariances.

Implemented a new blinding procedure to prevent confirmation bias.

Abstract

We present a joint cosmological analysis of projected galaxy clustering observations from the Dark Energy Spectroscopic Instrument Data Release 1 (DESI-DR1), and overlapping weak gravitational lensing observations from three datasets: the Kilo-Degree Survey (KiDS-1000), the Dark Energy Survey (DES-Y3), and the Hyper-Suprime-Cam Survey (HSC-Y3). This combination of large-scale structure probes allows us to measure a set of $3 \times 2$-pt correlation functions, breaking the degeneracies between parameters in cosmological fits to individual observables. We obtain mutually-consistent constraints on the parameter $S_8 = \sigma_8 \sqrt{\Omega_{\rm m}/0.3} = 0.786^{+0.022}_{-0.019}$ from the combination of DESI-DR1 and DES-Y3, $S_8 = 0.760^{+0.020}_{-0.018}$ from KiDS-1000, and $S_8 = 0.771^{+0.026}_{-0.027}$ from HSC-Y3. These parameter determinations are consistent with fits to the Planck Cosmic Microwave Background dataset, albeit with $1.5-2\sigma$ lower values in the $S_8-\Omega_{\rm m}$ plane. We perform our analysis with a unified pipeline tailored to the requirements of each cosmic shear survey, which self-consistently determines cosmological and astrophysical parameters. We generate an analytical covariance matrix for the correlation data including all cross-covariances between probes, and we design a new blinding procedure to safeguard our analysis against confirmation bias, whilst leaving goodness-of-fit statistics unchanged. Our study is part of a suite of papers that present joint cosmological analyses of DESI-DR1 and weak gravitational lensing datasets.