Constraining the phase shift of relativistic species in DESI BAOs

ABSTRACT In the early Universe, neutrinos decouple quickly from the primordial plasma and propagate without further interactions. The impact of free-streaming neutrinos is to create a temporal shift in the gravitational potential that impacts the acoustic waves known as baryon acoustic oscillations (BAOs), resulting in a non-linear spatial shift in the Fourier-space BAO signal. In this work, we make use of and extend upon an existing methodology to measure the phase shift amplitude $\beta _{\phi }$ and apply it to the Dark Energy Spectroscopic Instrument (DESI) Data Release 1 (DR1) BAOs with an anisotropic BAO fitting pipeline. We validate the fitting methodology by testing the pipeline with two publicly available fitting codes applied to highly precise cubic box simulations and realistic simulations representative of the DESI DR1 data. We find further study towards the methods used in fitting the BAO signal will be necessary to ensure accurate constraints on $\beta _{\phi }$ in future DESI data releases. Using DESI DR1, we present individual measurements of the anisotropic BAO distortion parameters and the $\beta _{\phi }$ for the different tracers, and additionally a combined fit to $\beta _{\phi }$ resulting in $\beta _{\phi } = 2.7 \pm 1.7$. After including a prior on the distortion parameters from constraints using Planck we find $\beta _{\phi } = 2.7^{+0.60}_{-0.67}$ suggesting $\beta _{\phi } > 0$ at 4.3$\sigma$ significance. This result may hint at a phase shift that is not purely sourced from the standard model expectation for $N_{\rm {eff}}$ or could be a upwards statistical fluctuation in the measured $\beta _{\phi }$; this result relaxes in models with additional freedom beyond Lambda-cold dark matter.

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Publication Details

Journal
Monthly Notices of the Royal Astronomical Society
Published
2025-03-11
DOI
https://doi.org/10.1093/mnras/staf394
Citations
11
Primary Topic
Astrophysics and Cosmic Phenomena
Type
article
Field-Weighted Citation Impact
20.57

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article

Constraining the phase shift of relativistic species in DESI BAOs

Abbé M Whitford, S. Juneau, Michael S. Schubnell, David Brooks et al.
11 citations
Monthly Notices of the Royal Astronomical Society
Astrophysics and Cosmic Phenomena
20.57
article

Constraining the phase shift of relativistic species in DESI BAOs

Abbé M Whitford, S. Juneau, Michael S. Schubnell, David Brooks, Graziano Rossi, Gregory Tarlé, Laurent Le Guillou, David Sprayberry, D. Bianchi, Ignasi Pérez-Ràfols, Axel de la Macorra, Martin Landriau, Simone Ferraro, S. Fromenteau, Eusebio Sanchez, Satya Gontcho A Gontcho, David Kirkby, ENRIQUE GAZTAÑAGA, J. E. Forero-Romero, T. M. Davis, Steven P. Ahlen, Aaron Meisner, Sergey E. Koposov, Pauline Zarrouk, Theodore S. Kisner, Arnaud de Mattia, M. Vargas-Magaña, F. Prada, Hu Zou, Benjamin A. Weaver, R. Kehoe, Ramon Miquel, Peter Doel, Gaston Gutierrez, T. Claybaugh, E. Burtin
article en
11 citations

Abstract

ABSTRACT In the early Universe, neutrinos decouple quickly from the primordial plasma and propagate without further interactions. The impact of free-streaming neutrinos is to create a temporal shift in the gravitational potential that impacts the acoustic waves known as baryon acoustic oscillations (BAOs), resulting in a non-linear spatial shift in the Fourier-space BAO signal. In this work, we make use of and extend upon an existing methodology to measure the phase shift amplitude $\beta _{\phi }$ and apply it to the Dark Energy Spectroscopic Instrument (DESI) Data Release 1 (DR1) BAOs with an anisotropic BAO fitting pipeline. We validate the fitting methodology by testing the pipeline with two publicly available fitting codes applied to highly precise cubic box simulations and realistic simulations representative of the DESI DR1 data. We find further study towards the methods used in fitting the BAO signal will be necessary to ensure accurate constraints on $\beta _{\phi }$ in future DESI data releases. Using DESI DR1, we present individual measurements of the anisotropic BAO distortion parameters and the $\beta _{\phi }$ for the different tracers, and additionally a combined fit to $\beta _{\phi }$ resulting in $\beta _{\phi } = 2.7 \pm 1.7$. After including a prior on the distortion parameters from constraints using Planck we find $\beta _{\phi } = 2.7^{+0.60}_{-0.67}$ suggesting $\beta _{\phi } > 0$ at 4.3$\sigma$ significance. This result may hint at a phase shift that is not purely sourced from the standard model expectation for $N_{\rm {eff}}$ or could be a upwards statistical fluctuation in the measured $\beta _{\phi }$; this result relaxes in models with additional freedom beyond Lambda-cold dark matter.

Monthly Notices of the Royal Astronomical SocietyVol. 538(3)
Boston University (US), Institució Catalana de Recerca i Estudis Avançats (ES), Universidad Complutense de Madrid (ES), Centre National de la Recherche Scientifique (FR), Fermi National Accelerator Laboratory (US), Institute of Space Sciences (ES), Lawrence Berkeley National Laboratory (US), State Street (United States) (US), Universidad de Los Andes (CO), The University of Queensland (AU), Southern Methodist University (US), Institute for High Energy Physics (ES), University of Milan (IT), Chinese Academy of Sciences (CN), University of California, Irvine (US), University of Cambridge (GB), Commissariat à l'Énergie Atomique et aux Énergies Alternatives (FR), Université Paris-Saclay (FR), University of Michigan (US), Sejong University (KR), Sorbonne Université (FR), Max Planck Institute for Extraterrestrial Physics (DE), Institut d'Estudis Espacials de Catalunya (ES), Laboratoire de Physique Nucléaire et de Hautes Énergies (FR), Royal Observatory (GB), Institute of Space Sciences (ES), Institute of Astronomy (RU), CEA Paris-Saclay (FR), Institut National de Physique Nucléaire et de Physique des Particules (FR), Community Science and Data Center (US), NSF NOIRLab (US), Universidad de Los Andes (BO), Instituto de Astrofísica de Andalucía (ES), National Astronomical Observatories (CN), Institut de Recherche sur les Lois Fondamentales de l'Univers (FR), Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (ES), Institute of Science and Technology, University College London (GB), University of Portsmouth (GB), Universidad Autónoma del Estado de Morelos (MX), Universidad Nacional Autónoma de México (MX), University of California, Berkeley (US), Universitat Politècnica de Catalunya (ES), University of Edinburgh (GB)
National Science Foundation, U.S. Department of Energy, National Aeronautics and Space Administration, Gordon and Betty Moore Foundation, Ministerio de Ciencia, Innovación y Universidades, Australian Government, Durham University, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Office of Science, Science and Technology Facilities Council, Agencia Estatal de Investigación, Division of Astronomical Sciences
Openalex Percentile: Top 1%
Astrophysics and Cosmic Phenomena
20.57
DOIOpen Access PDFOpenAlex
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