Engineering Papers⌕ Search
Home/Archive/DOE OSTI

DOE OSTI · 3010011

Early time solution as an alternative to the late time evolving dark energy with DESI DR2 BAO

Chaussidon, E. [Lawrence Berkeley National Laboratory] (ORCID:0000000189964874)·White, M. [University of California, Berkeley; University of California, Berkeley] (ORCID:0000000199125070)·de Mattia, A. [IRFU; CEA; Université Paris-Saclay] (ORCID:0000000309202947)·Gsponer, R. [École Polytechnique Fédérale de Lausanne (EPFL)] (ORCID:0000000275407601)·Ahlen, S. [Boston University] (ORCID:0000000160987247)·Bianchi, D. [Università degli Studi di Milano; INAF-Osservatorio Astronomico di Brera] (ORCID:0000000197120006)·Brooks, D. [University College London]·Claybaugh, T. [Lawrence Berkeley National Laboratory]·Cole, S. [Durham University] (ORCID:0000000259547903)·Cuceu, A. [Lawrence Berkeley National Laboratory] (ORCID:0000000221690595)·de la Macorra, A. [Universidad Nacional Autónoma de México] (ORCID:0000000217691640)·Doel, P. [University College London]·Ferraro, S. [Lawrence Berkeley National Laboratory; University of California, Berkeley] (ORCID:0000000349927854)·Font-Ribera, A. [Institut de Física d’Altes Energies (IFAE)] (ORCID:0000000230337312)·Forero-Romero, J. E. [Universidad de los Andes; Universidad de los Andes] (ORCID:0000000228903725)·Gaztañaga, E. [Institut d’Estudis Espacials de Catalunya (IEEC); University of Portsmouth; Institute of Space Sciences]·Gontcho, S. Gontcho A. [Lawrence Berkeley National Laboratory]·Gutierrez, G. [Fermi National Accelerator Laboratory]·Guy, J. [Lawrence Berkeley National Laboratory] (ORCID:0000000198226793)·Hahn, C. [University of Arizona] (ORCID:0000000311970902)·Herrera-Alcantar, H. K. [Institut d’Astrophysique de Paris; IRFU; CEA; Université Paris-Saclay] (ORCID:0000000291369609)·Honscheid, K. [The Ohio State University; The Ohio State University; The Ohio State University] (ORCID:0000000265502023)·Ishak, M. [The University of Texas at Dallas] (ORCID:000000026024466X)·Kirkby, D. [University of California, Irvine] (ORCID:0000000288285463)·Kisner, T. [Lawrence Berkeley National Laboratory] (ORCID:0000000335107134)·Kremin, A. [Lawrence Berkeley National Laboratory] (ORCID:0000000163567424)·Landriau, M. [Lawrence Berkeley National Laboratory] (ORCID:0000000318388528)·Le Guillou, L. [Sorbonne Université; CNRS; IN2P3; Laboratoire de Physique Nucléaire et de Hautes Energies (LPNHE)] (ORCID:0000000171788868)·Levi, M. E. [Lawrence Berkeley National Laboratory] (ORCID:0000000318871018)·Miquel, R. [Institució Catalana de Recerca i Estudis Avançats; Institut de Física d’Altes Energies (IFAE)]·Moustakas, J. [Siena College] (ORCID:0000000227334559)·Niz, G. [Universidad de Guanajuato; Instituto Avanzado de Cosmología A. C.] (ORCID:0000000215448946)·Percival, W. J. [University of Waterloo; Perimeter Institute; University of Waterloo] (ORCID:0000000206445727)·Prada, F. [Instituto de Astrofísica de Andalucía] (ORCID:0000000171458674)·Pérez-Ràfols, I. [Universitat Politècnica de Catalunya] (ORCID:0000000169790125)·Ross, A. J. [The Ohio State University; The Ohio State University; The Ohio State University] (ORCID:0000000275229083)·Rossi, G. [Sejong University]·Sanchez, E. [CIEMAT] (ORCID:0000000296468198)·Schlegel, D. [Lawrence Berkeley National Laboratory]·Seo, H. [Ohio University] (ORCID:0000000265883508)·Sprayberry, D. [NSF NOIRLab]·Walther, M. [Excellence Cluster ORIGINS; Ludwig-Maximilians-Universität] (ORCID:0000000217483745)·Weaver, B. A. [NSF NOIRLab]
View original source ↗Read source document ↗Export metadata ↓

Abstract

Recently the Dark Energy Spectroscopic Instrument (DESI) provided constraints on the expansion history from their Data Release 2. The DESI baryon acoustic oscillation measurements are well described by a flat Λ CDM model, but the preferred parameters are in mild ( 2.3 σ ) tension with those determined from the cosmic microwave background. The DESI Collaboration has already explored a variety of solutions to this tension relying on variations in the late-time evolution of dark energy. Here we test an alternative—the introduction of an “early dark energy” (EDE) component. We find that EDE models can alleviate the tension, though they lead to differences in other cosmological parameters that have observational implications. Particularly the EDE models that fit the acoustic datasets prefer lower Ω m , higher H 0 , n s and σ 8 in contrast to the late-time solutions. Finally, we discuss the current status and near-future prospects for distinguishing amongst these solutions.

Explore related subjects

Baryon acoustic oscillationscosmologydark energylarge-scale structure of the universe

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Chaussidon, E. [Lawrence Berkeley National Laboratory] (ORCID:0000000189964874), White, M. [University of California, Berkeley; University of California, Berkeley] (ORCID:0000000199125070), de Mattia, A. [IRFU; CEA; Université Paris-Saclay] (ORCID:0000000309202947), Gsponer, R. [École Polytechnique Fédérale de Lausanne (EPFL)] (ORCID:0000000275407601), Ahlen, S. [Boston University] (ORCID:0000000160987247), Bianchi, D. [Università degli Studi di Milano; INAF-Osservatorio Astronomico di Brera] (ORCID:0000000197120006), Brooks, D. [University College London], Claybaugh, T. [Lawrence Berkeley National Laboratory], Cole, S. [Durham University] (ORCID:0000000259547903), Cuceu, A. [Lawrence Berkeley National Laboratory] (ORCID:0000000221690595), de la Macorra, A. [Universidad Nacional Autónoma de México] (ORCID:0000000217691640), Doel, P. [University College London], Ferraro, S. [Lawrence Berkeley National Laboratory; University of California, Berkeley] (ORCID:0000000349927854), Font-Ribera, A. [Institut de Física d’Altes Energies (IFAE)] (ORCID:0000000230337312), Forero-Romero, J. E. [Universidad de los Andes; Universidad de los Andes] (ORCID:0000000228903725), Gaztañaga, E. [Institut d’Estudis Espacials de Catalunya (IEEC); University of Portsmouth; Institute of Space Sciences], Gontcho, S. Gontcho A. [Lawrence Berkeley National Laboratory], Gutierrez, G. [Fermi National Accelerator Laboratory], Guy, J. [Lawrence Berkeley National Laboratory] (ORCID:0000000198226793), Hahn, C. [University of Arizona] (ORCID:0000000311970902), Herrera-Alcantar, H. K. [Institut d’Astrophysique de Paris; IRFU; CEA; Université Paris-Saclay] (ORCID:0000000291369609), Honscheid, K. [The Ohio State University; The Ohio State University; The Ohio State University] (ORCID:0000000265502023), Ishak, M. [The University of Texas at Dallas] (ORCID:000000026024466X), Kirkby, D. [University of California, Irvine] (ORCID:0000000288285463), Kisner, T. [Lawrence Berkeley National Laboratory] (ORCID:0000000335107134), Kremin, A. [Lawrence Berkeley National Laboratory] (ORCID:0000000163567424), Landriau, M. [Lawrence Berkeley National Laboratory] (ORCID:0000000318388528), Le Guillou, L. [Sorbonne Université; CNRS; IN2P3; Laboratoire de Physique Nucléaire et de Hautes Energies (LPNHE)] (ORCID:0000000171788868), Levi, M. E. [Lawrence Berkeley National Laboratory] (ORCID:0000000318871018), Miquel, R. [Institució Catalana de Recerca i Estudis Avançats; Institut de Física d’Altes Energies (IFAE)], Moustakas, J. [Siena College] (ORCID:0000000227334559), Niz, G. [Universidad de Guanajuato; Instituto Avanzado de Cosmología A. C.] (ORCID:0000000215448946), Percival, W. J. [University of Waterloo; Perimeter Institute; University of Waterloo] (ORCID:0000000206445727), Prada, F. [Instituto de Astrofísica de Andalucía] (ORCID:0000000171458674), Pérez-Ràfols, I. [Universitat Politècnica de Catalunya] (ORCID:0000000169790125), Ross, A. J. [The Ohio State University; The Ohio State University; The Ohio State University] (ORCID:0000000275229083), Rossi, G. [Sejong University], Sanchez, E. [CIEMAT] (ORCID:0000000296468198), Schlegel, D. [Lawrence Berkeley National Laboratory], Seo, H. [Ohio University] (ORCID:0000000265883508), Sprayberry, D. [NSF NOIRLab], Walther, M. [Excellence Cluster ORIGINS; Ludwig-Maximilians-Universität] (ORCID:0000000217483745), Weaver, B. A. [NSF NOIRLab]. 2025-09-25. Early time solution as an alternative to the late time evolving dark energy with DESI DR2 BAO. https://doi.org/10.1103/xtql-wh3h

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related reports

DOE OSTI2025

DESI DR2 results. II. Measurements of baryon acoustic oscillations and cosmological constraints

We present baryon acoustic oscillation (BAO) measurements from more than 14 million galaxies and quasars drawn from the Dark Energy Spectroscopic Instrument (DESI) Data Release 2 (DR2), based on three years of operation. For cosmology inference, these galaxy measurements are combined with DESI Lyman-𝛼 forest BAO results presented in a companion paper (M. Abdul-Karim et al., companion paper, Phys. Rev. D 112, 083514 2025.). The DR2 BAO results are consistent with DESI DR1 and the Sloan Digital Sky Survey, and their distance-redshift relationship matches those from recent compilations of supernovae (SNe) over the same redshift range. The results are well described by a flat Λ cold dark matter (Λ⁢CDM) model, but the parameters preferred by BAO are in mild, 2.3⁢𝜎 tension with those determined from the cosmic microwave background (CMB), although the DESI results are consistent with the acoustic angular scale 𝜃 * that is well measured by Planck. This tension is alleviated by dark energy with a time-evolving equation of state parametrized by 𝑤0 and 𝑤𝑎, which provides a better fit to the data, with a favored solution in the quadrant with 𝑤 0 >−1 and 𝑤 𝑎 <0. This solution is preferred over Λ ⁢CDM at 3.1⁢𝜎 for the combination of DESI BAO and CMB data. When also including SNe, the preference for a dynamical dark energy model over Λ⁢ CDM ranges from 2.8 − 4.2⁢𝜎 depending on which SNe sample is used. We present evidence from other data combinations which also favor the same behavior at high significance. From the combination of DESI and CMB we derive 95% upper limits on the sum of neutrino masses, finding ∑𝑚 𝜈 < 0.064 eV assuming Λ ⁢CDM and ∑𝑚 𝜈 < 0.16 eV in the 𝑤0⁢𝑤𝑎 model. Unless there is an unknown systematic error associated with one or more datasets, it is clear that Λ⁢ CDM is being challenged by the combination of DESI BAO with other measurements and that dynamical dark energy offers a possible solution.

Baryon acoustic oscillations↗
DOE OSTI2025

Monopole Fluctuations in Galaxy Surveys

Galaxy clustering provides a powerful way to probe cosmology. This requires understanding of the background mean density of galaxy samples, which is estimated from the survey itself by averaging the observed galaxy number density over the angular position. The angle average includes not only the background mean density but also the monopole fluctuation at each redshift. Here for the first time we compute the monopole fluctuations in galaxy surveys and investigate their impact on galaxy clustering. The monopole fluctuations vary as a function of redshift, and it is correlated with other fluctuations, affecting the two-point correlation function measurements. In an idealized all-sky survey, the rms fluctuation at z = 0.5 can be as large as 7% of the two-point correlation function in amplitude at the baryonic acoustic oscillation scale, and it becomes smaller than 1% at z > 2. The monopole fluctuations are unavoidable, but they can be modeled. We discuss its relation to the integral constraint and the implications for the galaxy clustering analysis.

Baryon acoustic oscillations↗