Dark energy survey year 1 results: Constraining baryonic physics in the Universe

Hung Jin Huang, Tim Eifler, Rachel Mandelbaum, Gary M. Bernstein, Anqi Chen, Ami Choi, Juan Garciá-Bellido, Dragan Huterer, Elisabeth Krause, Eduardo Rozo, Sukhdeep Singh, Sarah Bridle, Joseph Derose, Jack Elvin-Poole, Xiao Fang, Oliver Friedrich, Marco Gatti, Enrique Gaztanaga, Daniel Gruen, Will HartleyBen Hoyle, Mike Jarvis, Niall Maccrann, Vivian Miranda, Markus Rau, Judit Prat, Carles Sánchez, Simon Samuroff, Michael Troxel, Joe Zuntz, Tim Abbott, Michel Aguena, James Annis, Santiago Avila, Matthew Becker, Emmanuel Bertin, David Brooks, David Burke, Aurelio Carnero Rosell, Matias Carrasco Kind, Jorge Carretero, Francisco Javier Castander, Luiz Da Costa, Juan De Vicente, Jörg Dietrich, Peter Doel, Spencer Everett, Brenna Flaugher, Pablo Fosalba, Josh Frieman, Robert Gruendl, Gaston Gutierrez, Samuel Hinton, Klaus Honscheid, David James, Kyler Kuehn, Ofer Lahav, Marcos Lima, Marcio Maia, Jennifer Marshall, Felipe Menanteau, Ramon Miquel, Francisco Paz-Chinchon, Andrés Plazas Malagón, Kathy Romer, Aaron Roodman, Eusebio Sanchez, Vic Scarpine, Santiago Serrano, Ignacio Sevilla, Mathew Smith, Marcelle Soares-Santos, Eric Suchyta, Molly Swanson, Gregory Tarle, Diehl H. Thomas, Jochen Weller

Research output: Contribution to journalArticlepeer-review


Measurements of large-scale structure are interpreted using theoretical predictions for the matter distribution, including potential impacts of baryonic physics. We constrain the feedback strength of baryons jointly with cosmology using weak lensing and galaxy clustering observables (3 × 2pt) of Dark Energy Survey (DES) Year 1 data in combination with external information from baryon acoustic oscillations (BAO) and Planck cosmic microwave background polarization. Our baryon modelling is informed by a set of hydrodynamical simulations that span a variety of baryon scenarios; we span this space via a Principal Component (PC) analysis of the summary statistics extracted from these simulations. We show that at the level of DES Y1 constraining power, one PC is sufficient to describe the variation of baryonic effects in the observables, and the first PC amplitude (Q1) generally reflects the strength of baryon feedback. With the upper limit of Q1 prior being bound by the Illustris feedback scenarios, we reach $\sim 20{{\ \rm per\ cent}}$ improvement in the constraint of $S_8=\sigma _8(\Omega _{\rm m}/0.3)^{0.5}=0.788^{+0.018}_{-0.021}$ compared to the original DES 3 × 2pt analysis. This gain is driven by the inclusion of small-scale cosmic shear information down to 2.5 arcmin, which was excluded in previous DES analyses that did not model baryonic physics. We obtain $S_8=0.781^{+0.014}_{-0.015}$ for the combined DES Y1+Planck EE+BAO analysis with a non-informative Q1 prior. In terms of the baryon constraints, we measure $Q_1=1.14^{+2.20}_{-2.80}$ for DES Y1 only and $Q_1=1.42^{+1.63}_{-1.48}$ for DESY1+Planck EE+BAO, allowing us to exclude one of the most extreme AGN feedback hydrodynamical scenario at more than 2σ.

Original languageEnglish (US)
Pages (from-to)6010-6031
Number of pages22
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
StatePublished - Apr 1 2021


  • cosmological parameters
  • cosmology: theory
  • large-scale structure of Universe

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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