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<p>Understanding whether cosmic acceleration arises from a cosmological constant or a dynamical component is a central goal of cosmology, and the Dark Energy Spectroscopic Instrument (DESI) enables stringent tests with high-precision distance measurements. Here we analyse measurements of baryon acoustic oscillations in DESI Data Release 1 and Data Release 2 and consider type Ia supernovae and a distance prior for the cosmic microwave background. With the larger statistical power and wider redshift coverage of Data Release 2, the preference for dynamical dark energy does not diminish relative to Data Release 1. Using both a shape-function reconstruction and non-parametric approaches with a Horndeski-motivated correlation prior, we find that the equation of state for dark energy <i>w</i>(<i>z</i>) varies with redshift. Baryon acoustic oscillation data alone yield modest constraints, but in combination with independent supernova compilations and the prior for the cosmic microwave background, they strengthen the evidence for dynamics. A Bayesian comparison of models shows moderate support for departures from <i>Λ</i> cold dark matter (<i>Λ</i>CDM) when several degrees of freedom in <i>w</i>(<i>z</i>) are allowed, corresponding to ~3<i>σ</i> tension with <i>Λ</i>CDM (and higher for some datasets). Despite methodological differences, our results are consistent with companion DESI papers, underscoring the complementarity of the approaches. Possible systematics remain under study; forthcoming DESI, Euclid and next-generation cosmic microwave background data will provide decisive tests.</p>

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Dynamical dark energy in light of the DESI DR2 baryonic acoustic oscillations measurements

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2025年9月29日

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  • Gan Gu,
  • Xiaoma Wang,
  • Yuting Wang,
  • Gong-Bo Zhao,
  • Levon Pogosian,
  • Kazuya Koyama,
  • John A. Peacock,
  • Zheng Cai,
  • Jorge L. Cervantes-Cota,
  • Mustapha Ishak,
  • Arman Shafieloo,
  • Ruiyang Zhao,
  • Steven Ahlen,
  • Davide Bianchi,
  • David Brooks,
  • Todd Claybaugh,
  • Shaun Cole,
  • Axel de la Macorra,
  • Arnaud de Mattia,
  • Peter Doel,
  • Simone Ferraro,
  • Jaime E. Forero-Romero,
  • Enrique Gaztañaga,
  • Satya Gontcho A Gontcho,
  • Gaston Gutierrez,
  • ChangHoon Hahn,
  • Cullan Howlett,
  • Robert Kehoe,
  • David Kirkby,
  • Jean-Paul Kneib,
  • Anthony Kremin,
  • Ofer Lahav,
  • Martin Landriau,
  • Laurent Le Guillou,
  • Alexie Leauthaud,
  • Michael Levi,
  • Marc Manera,
  • Aaron Meisner,
  • Ramon Miquel,
  • John Moustakas,
  • Andrea Muñoz-Gutiérrez,
  • Seshadri Nadathur,
  • Jeffrey A. Newman,
  • Nathalie Palanque-Delabrouille,
  • Will Percival,
  • Francisco Prada,
  • Ignasi Pérez-Ràfols,
  • Graziano Rossi,
  • Lado Samushia,
  • Eusebio Sanchez,
  • David Schlegel,
  • Hee-Jong Seo,
  • David Sprayberry,
  • Gregory Tarlé,
  • Michael Walther,
  • Benjamin Alan Weaver,
  • Pauline Zarrouk,
  • Cheng Zhao,
  • Rongpu Zhou,
  • Hu Zou

摘要

Understanding whether cosmic acceleration arises from a cosmological constant or a dynamical component is a central goal of cosmology, and the Dark Energy Spectroscopic Instrument (DESI) enables stringent tests with high-precision distance measurements. Here we analyse measurements of baryon acoustic oscillations in DESI Data Release 1 and Data Release 2 and consider type Ia supernovae and a distance prior for the cosmic microwave background. With the larger statistical power and wider redshift coverage of Data Release 2, the preference for dynamical dark energy does not diminish relative to Data Release 1. Using both a shape-function reconstruction and non-parametric approaches with a Horndeski-motivated correlation prior, we find that the equation of state for dark energy w(z) varies with redshift. Baryon acoustic oscillation data alone yield modest constraints, but in combination with independent supernova compilations and the prior for the cosmic microwave background, they strengthen the evidence for dynamics. A Bayesian comparison of models shows moderate support for departures from Λ cold dark matter (ΛCDM) when several degrees of freedom in w(z) are allowed, corresponding to ~3σ tension with ΛCDM (and higher for some datasets). Despite methodological differences, our results are consistent with companion DESI papers, underscoring the complementarity of the approaches. Possible systematics remain under study; forthcoming DESI, Euclid and next-generation cosmic microwave background data will provide decisive tests.