Dark Energy Survey Year 3 Results: Cosmology from Cosmic Shear and Robustness to Modeling Uncertainty
read the original abstract
This work and its companion paper, Amon et al. (2021), present cosmic shear measurements and cosmological constraints from over 100 million source galaxies in the Dark Energy Survey (DES) Year 3 data. We constrain the lensing amplitude parameter $S_8\equiv\sigma_8\sqrt{\Omega_\textrm{m}/0.3}$ at the 3% level in $\Lambda$CDM: $S_8=0.759^{+0.025}_{-0.023}$ (68% CL). Our constraint is at the 2% level when using angular scale cuts that are optimized for the $\Lambda$CDM analysis: $S_8=0.772^{+0.018}_{-0.017}$ (68% CL). With cosmic shear alone, we find no statistically significant constraint on the dark energy equation-of-state parameter at our present statistical power. We carry out our analysis blind, and compare our measurement with constraints from two other contemporary weak-lensing experiments: the Kilo-Degree Survey (KiDS) and Hyper-Suprime Camera Subaru Strategic Program (HSC). We additionally quantify the agreement between our data and external constraints from the Cosmic Microwave Background (CMB). Our DES Y3 result under the assumption of $\Lambda$CDM is found to be in statistical agreement with Planck 2018, although favors a lower $S_8$ than the CMB-inferred value by $2.3\sigma$ (a $p$-value of 0.02). This paper explores the robustness of these cosmic shear results to modeling of intrinsic alignments, the matter power spectrum and baryonic physics. We additionally explore the statistical preference of our data for intrinsic alignment models of different complexity. The fiducial cosmic shear model is tested using synthetic data, and we report no biases greater than 0.3$\sigma$ in the plane of $S_8\times\Omega_\textrm{m}$ caused by uncertainties in the theoretical models.
This paper has not been read by Pith yet.
Forward citations
Cited by 10 Pith papers
-
Density-Shear Baryon Acoustic Oscillation as a Cosmological Consistency Check
GI BAO provides a robust consistency check for density BAO and shear data, with the first photometric measurement on DES Y3 showing agreement at α = 0.966 ± 0.252.
-
Density-Shear Baryon Acoustic Oscillation as a Cosmological Consistency Check
First GI BAO measurement from DES Y3 photometric data yields α = 0.966 ± 0.252, consistent with density BAO α = 0.966 ± 0.037 at 0.86σ detection.
-
AKRA 3.0: A matrix-free Inversion Framework for Weak Lensing Mass Mapping and Its Application to DES Y3 Data
AKRA 3.0 uses conjugate gradient to solve the normal equations for weak lensing mass mapping, producing the highest-resolution DES Y3 convergence map to date and demonstrating unbiased power spectra extracted directly...
-
Signatures of Suppressed Matter Clustering revealed by Fast Radio Bursts
FRB dispersion measures directly constrain suppression of the matter power spectrum due to feedback at k ~ 0.1-3 h/Mpc, reduce posterior variance by a factor of ~8 at k~1 h/Mpc, and exclude extreme large-scale feedbac...
-
Nonlinear Matter Power Spectrum from relativistic $N$-body Simulations: $\Lambda_{\rm s}$CDM versus $\Lambda$CDM
Relativistic N-body simulations of Lambda_s CDM produce a redshift-dependent crest in the matter power spectrum ratio, peaking at 20-25% near the transition and leaving a 15-20% uplift at z=0 on group scales.
-
Modeling nonlinear scales for dynamical dark energy cosmologies with COLA
COLA-based hybrid emulator reproduces nonlinear power spectrum boosts in w0wa models to <2% error vs EuclidEmulator2 and produces <0.3σ shifts in LSST-like cosmic shear parameter constraints.
-
$4\times3$ Point Correlation Functions in Galaxy Surveys: Impact of Baryonic Feedback
Baryonic feedback affects galaxy-galaxy, galaxy-shear, and shear-shear three-point correlation functions more strongly than two-point functions on small scales, reaching up to 90 percent suppression depending on redsh...
-
Do equation of state parametrizations of dark energy faithfully capture the dynamics of the late universe?
Node-based reconstruction of cosmic expansion prefers stronger deceleration at z≈1.7 than smooth DE EoS parametrizations, isolating z~1.5-2 as a window where the latter may compress localized kinematic features permit...
-
The sound of dynamical dark energy and modified gravity
Using CMB, SN, BAO and shear data, the work shows dynamical dark energy in MG models correlates with deviations from GR below z=2 at >95% CL, a link that holds for varying sound speed but vanishes for a cosmological constant.
-
Cosmic Shear constraints from HSC Year 3 with clustering calibration of the tomographic redshift distributions from DESI
Reanalysis of HSC Y3 cosmic shear with DESI clustering redshift calibration yields S8 = 0.805 ± 0.018, a 1.8× error reduction and upward shift toward Planck cosmology.
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.