Cosmological Constraints from Full-Scale Clustering and Galaxy-Galaxy Lensing with DESI DR1

TL;DR

This paper uses galaxy clustering and lensing data from DESI DR1 and other surveys to tightly constrain cosmological parameters, especially $S_8$ and $\,Omega_m$, leveraging non-linear scales and advanced modeling.

Contribution

It introduces a simulation-based modeling framework with a complex halo occupation distribution that includes assembly bias, enabling precise cosmological constraints from small-scale clustering and lensing.

Findings

Measured $S_8$ around 0.794 with ~0.02 uncertainty.

Determined $\,Omega_m$ near 0.30 with ~0.01 precision.

Results agree with previous studies, emphasizing non-linear scale constraints.

Abstract

We present constraints on cosmic structure growth from the analysis of galaxy clustering and galaxy-galaxy lensing with galaxies from the Dark Energy Spectroscopic Instrument (DESI) Data Release 1. We analyze four samples drawn from the Bright Galaxy Survey (BGS) and the Luminous Red Galaxy (LRG) target classes. Projected galaxy clustering measurements from DESI are supplemented with lensing measurements from the Dark Energy Survey (DES), the Kilo-Degree Survey (KiDS), and the Hyper Suprime-Cam (HSC) survey around the same targets. Our method relies on a simulation-based modeling framework using the AbacusSummit simulations and a complex halo occupation distribution model that incorporates assembly bias. We analyze scales down to $0.4 \, h^{-1} \, \mathrm{Mpc}$ for clustering and $2.5 \, h^{-1} \, \mathrm{Mpc}$ for lensing, leading to stringent constraints on $S_8 = \sigma_8 \sqrt{\Omega_\mathrm{m} / 0.3}$ and $\Omega_\mathrm{m}$ when fixing other cosmological parameters to those preferred by the CMB. We find $S_8 = 0.794 \pm 0.023$ and $\Omega_\mathrm{m} = 0.295 \pm 0.012$ when using lensing measurements from DES and KiDS. Similarly, for HSC, we find $S_8 = 0.793 \pm 0.017$ and $\Omega_\mathrm{m} = 0.303 \pm 0.010$ when assuming the best-fit photometric redshift offset suggested by the HSC collaboration. Overall, our results are in good agreement with other results in the literature while continuing to highlight the constraining power of non-linear scales.