DESI DR1 Lyα 1D power spectrum: the Fast Fourier Transform estimator measurement

Journal Article · Mon Nov 24 00:00:00 UTC 2025 · Journal of Cosmology and Astroparticle Physics

DOI: https://doi.org/10.1088/1475-7516/2025/11/079 · OSTI ID:3009999

Ravoux, Corentin  ^[1]; Abdul-Karim, Marie-Lynn ; Goff, Jean-Marc Le; Armengaud, Eric ; Aguilar, Jessica N.; Ahlen, Steven ; Bailey, Stephen ; Bianchi, Davide ; Brodzeller, Allyson ; Brooks, David; Chaves-Montero, Jonás ; Claybaugh, Todd; Cuceu, Andrei ; de Belsunce, Roger ; de la Macorra, Axel ; Dey, Arjun ; Ding, Zhejie ; Doel, Peter; Ferraro, Simone ; Font-Ribera, Andreu ; Forero-Romero, Jaime E. ; Gaztañaga, Enrique; Karaçaylı, Naim Göksel ; Gontcho, Satya Gontcho A. ; Gutierrez, Gaston; Guy, Julien ; Herrera-Alcantar, Hiram K. ; Ishak, Mustapha ; Kehoe, Robert; Kirkby, David ; Kisner, Theodore ; Kremin, Anthony ; Landriau, Martin ; Guillou, Laurent Le ; Levi, Michael E. ; Manera, Marc ; Martini, Paul ; Meisner, Aaron ; Miquel, Ramon; Montero-Camacho, Paulo ; Muñoz-Gutiérrez, Andrea; Nadathur, Seshadri ; Niz, Gustavo ; Palanque-Delabrouille, Nathalie ; Pan, Zhiwei ; Percival, Will J. ; Pérez-Ràfols, Ignasi ; Pieri, Matthew M. ; Prada, Francisco ; Rossi, Graziano; Sanchez, Eusebio ; Saulder, Christoph ; Schlegel, David; Schubnell, Michael; Seo, Hee-Jong ; Silber, Joseph H. ; Siudek, Małgorzata ; Sprayberry, David; Tan, Ting ; Tang, Ji-Jia ; Tarlé, Gregory ; Walther, Michael ; Weaver, Benjamin A.; Yèche, Christophe ; Yu, Jiaxi ; Zhou, Rongpu ; Zou, Hu

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1. Université Clermont-Auvergne, Clermont-Ferrand (France); Centre National de la Recherche Scientifique (CNRS), Clermont-Ferrand (France). Laboratoire de Physique de Clermont Auvergne (LPCA); DESI Collaboration. et al.

Here, we present the one-dimensional Lyman-α forest power spectrum measurement derived from the data release 1 (DR1) of the Dark Energy Spectroscopic Instrument (DESI). The measurement of the Lyman-α forest power spectrum along the line of sight from high-redshift quasar spectra provides information on the shape of the linear matter power spectrum, neutrino masses, and the properties of dark matter. In this work, we use a Fast Fourier Transform (FFT)-based estimator, which is validated on synthetic data in a companion paper. Compared to the FFT measurement performed on the DESI early data release, we improve the noise characterization with a cross-exposure estimator and test the robustness of our measurement using various data splits. We also refine the estimation of the uncertainties and now present an estimator for the covariance matrix of the measurement. Furthermore, we compare our results to previous high-resolution and eBOSS measurements. In another companion paper, we present the same DR1 measurement using the Quadratic Maximum Likelihood Estimator (QMLE). These two measurements are consistent with each other and constitute the most precise one-dimensional power spectrum measurement to date, while being in good agreement with results from the DESI early data release.

• Research Organization: Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Univ. of California, Irvine, CA (United States). Dept. of Physics and Astronomy; Univ. of Texas at Dallas, Richardson, TX (United States); University of Michigan, Ann Arbor, MI (United States)
• Sponsoring Organization: ANR; U.S. National Science Foundation (NSF), Division of Astronomical Sciences; USDOE Office of Science (SC), High Energy Physics (HEP)
• Grant/Contract Number: 89243024CSC000002; AC02-05CH11231; SC0009920; SC0019193; SC0022184
• OSTI ID: 3009999
• Report Number(s): FERMILAB-PUB--25-0347-PPD
• Journal Information: Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 11 Vol. 2025; ISSN 1475-7516
• Publisher: Institute of Physics (IOP)Copyright Statement
• Country of Publication: United States
• Language: English