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Dark Energy Survey Year 3 Results: Cosmological Constraints from Galaxy Clustering and Weak Lensing

DES Collaboration, T. M. C. Abbott, M. Aguena, A. Alarcon, S. Allam, O. Alves, A. Amon, F. Andrade-Oliveira, J. Annis, S. Avila, D. Bacon, E. Baxter, K. Bechtol, M. R. Becker, G. M. Bernstein, S. Bhargava, S. Birrer, J. Blazek, A. Brandao-Souza, S. L. Bridle, D. Brooks, E. Buckley-Geer, D. L. Burke, H. Camacho, A. Campos, A. Carnero Rosell, M. Carrasco Kind, J. Carretero, F. J. Castander, R. Cawthon, C. Chang, A. Chen, R. Chen, A. Choi, C. Conselice, J. Cordero, M. Costanzi, M. Crocce, L. N. da Costa, M. E. da Silva Pereira, C. Davis, T. M. Davis, J. De Vicente, J. DeRose, S. Desai, E. Di Valentino, H. T. Diehl, J. P. Dietrich, S. Dodelson, P. Doel, C. Doux, A. Drlica-Wagner, K. Eckert, T. F. Eifler, F. Elsner, J. Elvin-Poole, S. Everett, A. E. Evrard, X. Fang, A. Farahi, E. Fernandez, I. Ferrero, A. Ferté, P. Fosalba, O. Friedrich, J. Frieman, J. García-Bellido, M. Gatti, E. Gaztanaga, D. W. Gerdes, T. Giannantonio, G. Giannini, D. Gruen, R. A. Gruendl, J. Gschwend, G. Gutierrez, I. Harrison, W. G. Hartley, K. Herner, S. R. Hinton, D. L. Hollowood, K. Honscheid, B. Hoyle, E. M. Huff, D. Huterer, B. Jain, D. J. James, M. Jarvis, N. Jeffrey, T. Jeltema, A. Kovacs, E. Krause, R. Kron, K. Kuehn, N. Kuropatkin, O. Lahav, P. -F. Leget, P. Lemos, A. R. Liddle, C. Lidman, M. Lima, H. Lin, N. MacCrann, M. A. G. Maia, J. L. Marshall, P. Martini, J. McCullough, P. Melchior, J. Mena-Fernández, F. Menanteau, R. Miquel, J. J. Mohr, R. Morgan, J. Muir, J. Myles, S. Nadathur, A. Navarro-Alsina, R. C. Nichol, R. L. C. Ogando, Y. Omori, A. Palmese, S. Pandey, Y. Park, F. Paz-Chinchón, D. Petravick, A. Pieres, A. A. Plazas Malagón, A. Porredon, J. Prat, M. Raveri, M. Rodriguez-Monroy, R. P. Rollins, A. K. Romer, A. Roodman, R. Rosenfeld, A. J. Ross, E. S. Rykoff, S. Samuroff, C. Sánchez, E. Sanchez, J. Sanchez, D. Sanchez Cid, V. Scarpine, M. Schubnell, D. Scolnic, L. F. Secco, S. Serrano, I. Sevilla-Noarbe, E. Sheldon, T. Shin, M. Smith, M. Soares-Santos, E. Suchyta, M. E. C. Swanson, M. Tabbutt, G. Tarle, D. Thomas, C. To, A. Troja, M. A. Troxel, D. L. Tucker, I. Tutusaus, T. N. Varga, A. R. Walker, N. Weaverdyck, R. Wechsler, J. Weller, B. Yanny, B. Yin, Y. Zhang, J. Zuntz

TL;DR

DES Year 3资本izes on a 3×2pt analysis (galaxy clustering, cosmic shear, and galaxy–galaxy lensing) over ~5000 deg^2 to tightly constrain low-redshift structure growth and geometry within ΛCDM and wCDM. The study integrates advanced redshift calibration (SOMPZ/Balrog/Hyperrank), blending-aware shear bias corrections, non-Limber clustering, and a robust cross-check framework via two independent likelihood pipelines (CosmoSIS and CosmoLike). It reports a high-precision DES+external data joint constraint: S8≈0.812, Ωm≈0.306 in ΛCDM with ∑mν<0.13 eV (95% CL); in wCDM, w≈-1.031 with similar precision. Overall, DES Y3 finds consistency with Planck CMB for ΛCDM, improves over DES Y1 by ~2× in precision, and demonstrates the power of multi-probe, self-calibrating analyses for forthcoming Stage IV surveys.

Abstract

We present the first cosmology results from large-scale structure in the Dark Energy Survey (DES) spanning 5000 deg$^2$. We perform an analysis combining three two-point correlation functions (3$\times$2pt): (i) cosmic shear using 100 million source galaxies, (ii) galaxy clustering, and (iii) the cross-correlation of source galaxy shear with lens galaxy positions. The analysis was designed to mitigate confirmation or observer bias; we describe specific changes made to the lens galaxy sample following unblinding of the results. We model the data within the flat $Λ$CDM and $w$CDM cosmological models. We find consistent cosmological results between the three two-point correlation functions; their combination yields clustering amplitude $S_8=0.776^{+0.017}_{-0.017}$ and matter density $Ω_{\mathrm{m}} = 0.339^{+0.032}_{-0.031}$ in $Λ$CDM, mean with 68% confidence limits; $S_8=0.775^{+0.026}_{-0.024}$, $Ω_{\mathrm{m}} = 0.352^{+0.035}_{-0.041}$, and dark energy equation-of-state parameter $w=-0.98^{+0.32}_{-0.20}$ in $w$CDM. This combination of DES data is consistent with the prediction of the model favored by the Planck 2018 cosmic microwave background (CMB) primary anisotropy data, which is quantified with a probability-to-exceed $p=0.13$ to $0.48$. When combining DES 3$\times$2pt data with available baryon acoustic oscillation, redshift-space distortion, and type Ia supernovae data, we find $p=0.34$. Combining all of these data sets with Planck CMB lensing yields joint parameter constraints of $S_8 = 0.812^{+0.008}_{-0.008}$, $Ω_{\mathrm{m}} = 0.306^{+0.004}_{-0.005}$, $h=0.680^{+0.004}_{-0.003}$, and $\sum m_ν<0.13 \;\mathrm{eV\; (95\% \;CL)}$ in $Λ$CDM; $S_8 = 0.812^{+0.008}_{-0.008}$, $Ω_{\mathrm{m}} = 0.302^{+0.006}_{-0.006}$, $h=0.687^{+0.006}_{-0.007}$, and $w=-1.031^{+0.030}_{-0.027}$ in $w$CDM. (abridged)

Dark Energy Survey Year 3 Results: Cosmological Constraints from Galaxy Clustering and Weak Lensing

TL;DR

DES Year 3资本izes on a 3×2pt analysis (galaxy clustering, cosmic shear, and galaxy–galaxy lensing) over ~5000 deg^2 to tightly constrain low-redshift structure growth and geometry within ΛCDM and wCDM. The study integrates advanced redshift calibration (SOMPZ/Balrog/Hyperrank), blending-aware shear bias corrections, non-Limber clustering, and a robust cross-check framework via two independent likelihood pipelines (CosmoSIS and CosmoLike). It reports a high-precision DES+external data joint constraint: S8≈0.812, Ωm≈0.306 in ΛCDM with ∑mν<0.13 eV (95% CL); in wCDM, w≈-1.031 with similar precision. Overall, DES Y3 finds consistency with Planck CMB for ΛCDM, improves over DES Y1 by ~2× in precision, and demonstrates the power of multi-probe, self-calibrating analyses for forthcoming Stage IV surveys.

Abstract

We present the first cosmology results from large-scale structure in the Dark Energy Survey (DES) spanning 5000 deg. We perform an analysis combining three two-point correlation functions (32pt): (i) cosmic shear using 100 million source galaxies, (ii) galaxy clustering, and (iii) the cross-correlation of source galaxy shear with lens galaxy positions. The analysis was designed to mitigate confirmation or observer bias; we describe specific changes made to the lens galaxy sample following unblinding of the results. We model the data within the flat CDM and CDM cosmological models. We find consistent cosmological results between the three two-point correlation functions; their combination yields clustering amplitude and matter density in CDM, mean with 68% confidence limits; , , and dark energy equation-of-state parameter in CDM. This combination of DES data is consistent with the prediction of the model favored by the Planck 2018 cosmic microwave background (CMB) primary anisotropy data, which is quantified with a probability-to-exceed to . When combining DES 32pt data with available baryon acoustic oscillation, redshift-space distortion, and type Ia supernovae data, we find . Combining all of these data sets with Planck CMB lensing yields joint parameter constraints of , , , and in CDM; , , , and in CDM. (abridged)

Paper Structure

This paper contains 46 sections, 25 equations, 28 figures, 8 tables.

Table of Contents

  1. Introduction
  2. Dark Energy Survey Data
  3. Source Galaxies
  4. Shapes
  5. Photometric redshifts
  6. Lens Galaxies
  7. MagLim sample
  8. redMaGiC sample
  9. Two-point Measurements
  10. Analysis
  11. Model
  12. Two-point statistics
  13. Parameterization and Priors
  14. Likelihood Analysis
  15. CosmoSIS
  16. ...and 31 more sections

Figures (28)

  • Figure 1: The source (top), MagLim lens (middle), and redMaGiC lens (bottom) redshift distributions. The histograms are normalized to integrate to the total weighted galaxy density (arcmin$^{-2}$) in each tomographic bin. The equivalent 1$\sigma$ uncertainties on the redshift distributions are indicated by the shaded regions. The distributions have been corrected by non-zero mean and width offsets derived in the relevant photo-$z$ uncertainty models. We adopt MagLim as our fiducial lens sample in this work, and use only redshift bins 1--4.
  • Figure 2: The measured $w(\theta)$ correlation functions for each tomographic bin $i$ of the MagLim lens galaxies (indicated by the $i,i$ label in each panel). The best-fit $\Lambda$CDM model from the fiducial 3$\times$2pt analysis is plotted as the solid line in the top part of each panel, while the bottom part of each panel shows the fractional difference between the measurements and the model prediction, $(w^{\textrm{obs.}}-w^{\textrm{th.}})/\sigma_w$ (with $y$-axis range $\pm 5\sigma$). In both the top and bottom part of each panel, 1$\sigma$ error bars are shown. Small angular scales where the linear galaxy bias assumption breaks down are not used in the cosmological analysis; these scales are indicated by grey shading. Bins 5 & 6 are not used in the final analysis.
  • Figure 3: The measured $\gamma_{t}(\theta)$ correlation functions for each tomographic bin combination using the MagLim sample. In each panel, the label $i, j$ refers to MagLim lens tomographic bin $i$ and the source bin $j$ The best-fit $\Lambda$CDM model from the fiducial 3$\times$2pt analysis is plotted as the solid line in the top part of each panel, with dotted curves indicating a negative model fit. The bottom part of each panel shows the fractional difference between the measurements and the model prediction, $(\gamma_t^{\textrm{obs.}}-\gamma_t^{\textrm{th.}})/\sigma_{\gamma_t}$ (with $y$-axis range $\pm 5\sigma$). In both the top and bottom part of each panel, 1$\sigma$ error bars are included. Small angular scales where the linear galaxy bias assumption breaks down are not used in the cosmological analysis; these scales are indicated by grey shading. Bins 5 & 6 are not used in the final analysis.
  • Figure 4: The measured small-scale shear ratio values for each tomographic bin combination using the MagLim sample, with 1$\sigma$ error bars indicated. The x-axis identifies the two source bins that make up the measured ratio. The best-fit cosmological model from the fiducial 3$\times$2pt analysis is over-plotted as the solid line for each set of lens-bin shear ratios.
  • Figure 5: The measured $\xi_{\pm}(\theta)$ correlation functions for each tomographic bin combination, with labels as described in Fig. \ref{['fig:gt']}. The best-fit $\Lambda$CDM model from the fiducial 3$\times$2pt analysis is plotted as the solid line in the top part of each panel, while the bottom part of each panel shows the fractional difference between the measurements and the model prediction, $(\xi_{\pm}^{\textrm{obs.}}-\xi_{\pm}^{\textrm{th.}})/\sigma_{\xi_{\pm}}$ (with $y$-axis range $\pm 5\sigma$). In both the top and bottom part of each panel, 1$\sigma$ error bars are included. The shaded regions (both light and dark) indicate scales not used in the fiducial analysis, primarily due to uncertainties in the impact of baryonic effects. The lighter shaded regions indicate scales that are used in an $\Lambda$CDM-optimized analysis, which meets our criterion for scale cuts described in Sec. \ref{['sec:method']} in $\Lambda$CDM only.
  • ...and 23 more figures