DESI 2024 VI: cosmological constraints from the measurements of baryon acoustic oscillations

• Published in: Journal of cosmology and astroparticle physics Vol. 2025; no. 2; pp. 021 - 90
• Main Authors: Adame, A.G., Alam, S., Alexander, D.M., Alves, O., Anand, A., Bailey, S., Bault, A., Beutler, F., Bianchi, D., Blum, R., Buckley-Geer, E., Burtin, E., Calderon, R., Chabanier, S., Chaves-Montero, J., Chen, X., Cuceu, A., de Mattia, A., Deiosso, N., Edelstein, J., Eftekharzadeh, S., Fagrelius, P., Fanning, K., Ferraro, S., Ereza, J., Forero-Romero, J.E., Frenk, C.S., Gaztañaga, E., Gil-Marín, H., Gonzalez-Morales, A.X., Gordon, C., Guy, J., Hadzhiyska, B., Hahn, C., Hanif, M.M.S., Herrera-Alcantar, H.K., Honscheid, K., Iršič, V., Juneau, S., Karaçaylı, N.G., Kirkby, D., Kremin, A., Krolewski, A., Lai, Y., Lasker, J., Le Goff, J.M., Le Guillou, L., Linder, E., Magneville, C., Manera, M., Margala, D., Martini, P., McDonald, P., Moore, S., Mueller, E., Myers, A.D., Nadathur, S., Napolitano, L., Neveux, R., Nguyen, N.M., Nie, J., Paillas, E., Palanque-Delabrouille, N., Penmetsa, S., Pieri, M.M., Pinon, M., Porredon, A., Prada, F., Ramírez-Pérez, C., Rashkovetskyi, M., Ravoux, C., Rezaie, M., Rocher, A., Roe, N.A., Rosado-Marin, A., Rossi, G., Ruhlmann-Kleider, V., Samushia, L., Sanchez, E., Saulder, C., Schlafly, E.F., Schlegel, D., Schubnell, M., Seo, H., Shafieloo, A., Silber, J., Sprayberry, D., Tan, T., Tarlé, G., Valdes, F., Vargas-Magaña, M., Walther, M., Wang, M.S., Yu, Y., Yuan, S., Zarrouk, P., Zhang, H., Zhao, C., Zhao, R., Zhuang, T.
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.02.2025; Institute of Physics (IOP)
• Subjects: Acoustics; Astronomical models; baryon acoustic oscillations; Baryons; Big bang cosmology; Constraints; Cosmic microwave background; cosmological parameters from LSS; Cosmology; Dark energy; dark energy experiments; Density; Energy equation; Equations of state; neutrino masses from cosmology; Neutrinos; Nuclear fusion; Nuclei (nuclear physics); Oscillations; Quasars; Red shift; Supernovae
• ISSN: 1475-7516; 1475-7516
• DOI: 10.1088/1475-7516/2025/02/021

We present cosmological results from the measurement of baryon acoustic oscillations (BAO)in galaxy, quasar and Lyman-α forest tracers from the first year of observations from theDark Energy Spectroscopic Instrument (DESI), to be released in the DESI Data Release 1. DESI BAOprovide robust measurements of the transverse comoving distance and Hubble rate, or theircombination, relative to the sound horizon, in seven redshift bins from over 6 millionextragalactic objects in the redshift range 0.1 < z < 4.2. To mitigate confirmation bias, a blindanalysis was implemented to measure the BAO scales. DESI BAO data alone are consistent with thestandard flat ΛCDM cosmological model with a matter density Ωm=0.295±0.015. Paired with abaryon density prior from Big Bang Nucleosynthesis and the robustly measured acoustic angularscale from the cosmic microwave background (CMB), DESI requires H0=(68.52±0.62) km s-1 Mpc-1. Inconjunction with CMB anisotropies from Planck and CMB lensing data from Planck and ACT, wefind Ωm=0.307± 0.005 and H0=(67.97±0.38) km s-1 Mpc-1. Extending the baseline model with aconstant dark energy equation of state parameter w, DESI BAO alone requirew=-0.99+0.15-0.13. In models with a time-varying dark energy equation of stateparametrised by w0 and wa, combinations of DESI with CMB or with type Ia supernovae (SN Ia)individually prefer w0 > -1 and wa < 0. This preference is 2.6σ for the DESI+CMBcombination, and persists or grows when SN Ia are added in, giving results discrepant with theΛCDM model at the 2.5σ, 3.5σ or 3.9σ levels for the addition of thePantheon+, Union3, or DES-SN5YR supernova datasets respectively. For the flat ΛCDM model withthe sum of neutrino mass ∑ mν free, combining the DESI and CMB data yields an upper limit∑ mν < 0.072 (0.113) eV at 95% confidence for a ∑ mν > 0 (∑ mν > 0.059) eVprior. These neutrino-mass constraints are substantially relaxed if the background dynamics areallowed to deviate from flat ΛCDM.