DOE OSTI · 2997659
DESI DR1 Ly$α$ forest: 3D full-shape analysis and cosmological constraints
Abstract
We perform an analysis of the full shapes of Lyman-$α$ (Ly$α$) forest correlation functions measured from the first data release (DR1) of the Dark Energy Spectroscopic Instrument (DESI). Our analysis focuses on measuring the Alcock-Paczynski (AP) effect and the cosmic growth rate times the amplitude of matter fluctuations in spheres of $8$$h^{-1}\text{Mpc}$, $fσ_8$. We validate our measurements using two different sets of mocks, a series of data splits, and a large set of analysis variations, which were first performed blinded. Our analysis constrains the ratio $D_M/D_H(z_\mathrm{eff})=4.525\pm0.071$, where $D_H=c/H(z)$ is the Hubble distance, $D_M$ is the transverse comoving distance, and the effective redshift is $z_\mathrm{eff}=2.33$. This is a factor of $2.4$ tighter than the Baryon Acoustic Oscillation (BAO) constraint from the same data. When combining with Ly$α$ BAO constraints from DESI DR2, we obtain the ratios $D_H(z_\mathrm{eff})/r_d=8.646\pm0.077$ and $D_M(z_\mathrm{eff})/r_d=38.90\pm0.38$, where $r_d$ is the sound horizon at the drag epoch. We also measure $fσ_8(z_\mathrm{eff}) = 0.37\; ^{+0.055}_{-0.065} \,(\mathrm{stat})\, \pm 0.033 \,(\mathrm{sys})$, but we do not use it for cosmological inference due to difficulties in its validation with mocks. In $Λ$CDM, our measurements are consistent with both cosmic microwave background (CMB) and galaxy clustering constraints. Using a nucleosynthesis prior but no CMB anisotropy information, we measure the Hubble constant to be $H_0 = 68.3\pm 1.6\;\,{\rm km\,s^{-1}\,Mpc^{-1}}$ within $Λ$CDM. Finally, we show that Ly$α$ forest AP measurements can help improve constraints on the dark energy equation of state, and are expected to play an important role in upcoming DESI analyses.
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Cuceu, Andrei [LBL, Berkeley; Chicago U., KICP] (ORCID:0000000221690595), Herrera-Alcantar, Hiram K. [Paris, Inst. Astrophys.; IRFU, Saclay] (ORCID:0000000291369609), Gordon, Calum [Barcelona, IFAE] (ORCID:0000000325615733), Ramírez-Pérez, César [Barcelona, IFAE], Armengaud, E. [IRFU, Saclay] (ORCID:0000000176005148), Font-Ribera, A. [Barcelona, IFAE] (ORCID:0000000230337312), Guy, J. [LBL, Berkeley] (ORCID:0000000198226793), Joachimi, B. [University Coll. London], Martini, P. [Chicago U., KICP; Ohio State U., Dept. Astron.; Ohio State U.] (ORCID:0000000242794182), Nadathur, S. [Portsmouth U., ICG] (ORCID:0000000190703102), Pérez-Ràfols, I. [Barcelona, Polytechnic U.] (ORCID:0000000169790125), Rich, J. [IRFU, Saclay; LPNHE, Paris], Aguilar, J. [LBL, Berkeley], Ahlen, S. [Boston U.] (ORCID:0000000160987247), Anand, A. [LBL, Berkeley] (ORCID:0000000329231585), Bailey, S. [LBL, Berkeley] (ORCID:0000000341626619), Bault, A. [LBL, Berkeley] (ORCID:0000000299641005), Bianchi, D. [Milan U.; Brera Observ.] (ORCID:0000000197120006), Brodzeller, A. [LBL, Berkeley] (ORCID:0000000289340954), Brooks, D. [University Coll. London], Chaves-Montero, J. [Barcelona, IFAE] (ORCID:0000000295534261), Claybaugh, T. [LBL, Berkeley], Dawson, K. S. [Utah U.] (ORCID:0000000205533805), de la Macorra, A. [UNAM, Mexico] (ORCID:0000000217691640), Della Costa, J. [San Diego State U.; Natl. Solar Observ., Tucson] (ORCID:0000000309282000), Doel, P. [University Coll. London], Ferraro, S. [LBL, Berkeley; UC, Berkeley, Math. Dept.] (ORCID:0000000349927854), Forero-Romero, J. E. [Andes U., Bogota] (ORCID:0000000228903725), Gaztañaga, E. [Barcelona, IEEC; Portsmouth U., ICG; ICE, Bellaterra] (ORCID:0000000196320815), Gontcho A. Gontcho, S. [LBL, Berkeley; Virginia U.] (ORCID:000000033142233X), Gonzalez-Morales, A. X. [Guanajuato U.] (ORCID:0000000340896924), Green, D. [LBL, Berkeley] (ORCID:0000000206763661), Gutierrez, G. [Fermilab], Hahn, C. [Arizona U., Astron. Dept. - Steward Observ.] (ORCID:0000000311970902), Herbold, M. [Ohio State U.] (ORCID:000900008112765X), Honscheid, K. [Chicago U., KICP; Ohio State U.] (ORCID:0000000265502023), Iršič, V. [IFPU, Trieste; SISSA, Trieste; Hertfordshire U.; Cambridge U., Inst. of Astron.] (ORCID:000000025445461X), Ishak, M. [U. Texas, Dallas] (ORCID:000000026024466X), Joyce, R. [Natl. Solar Observ., Tucson] (ORCID:0000000302015241), Karaçaylı, N. G. [Chicago U., KICP; Ohio State U., Dept. Astron.; Ohio State U.] (ORCID:0000000173368912), Kirkby, D. [UC, Irvine] (ORCID:0000000288285463), Kisner, T. [LBL, Berkeley] (ORCID:0000000335107134), Kremin, A. [LBL, Berkeley] (ORCID:0000000163567424), Lahav, O. [University Coll. London], Lambert, A. [LBL, Berkeley], Lamman, C. [Ohio State U.] (ORCID:0000000267319329), Landriau, M. [LBL, Berkeley] (ORCID:0000000318388528), Le Goff, J. M. [IRFU, Saclay], Le Guillou, L. [LPNHE, Paris] (ORCID:0000000171788868), Levi, M. E. [LBL, Berkeley] (ORCID:0000000318871018), Manera, M. [Barcelona, IFAE; Barcelona, Autonoma U.] (ORCID:0000000349628934), Meisner, A. [Natl. Solar Observ., Tucson] (ORCID:0000000211257384), Miquel, R. [ICREA, Barcelona; Barcelona, IFAE], Moustakas, J. [Siena Coll., Loudonville] (ORCID:0000000227334559), Muñoz-Gutiérrez, A. [UNAM, Mexico], Newman, J. A. [Pittsburgh U.] (ORCID:0000000186842222), Niz, G. [Guanajuato U.; Mexico U., ICN] (ORCID:0000000215448946), Palanque-Delabrouille, N. [IRFU, Saclay; LBL, Berkeley] (ORCID:000000033188784X), Percival, W. J. [Waterloo U.; Perimeter Inst. Theor. Phys.] (ORCID:0000000206445727), Pieri, Matthew M. [Marseille, Lab. Astrophys.] (ORCID:0000000302478991), Poppett, C. [LBL, Berkeley; UC, Berkeley, Space Sci. Dept.; UC, Berkeley, Math. Dept.], Prada, F. [Granada U., Theor. Phys. Astrophys.] (ORCID:0000000171458674), Ravoux, C. [LPC, Clermont-Ferrand] (ORCID:0000000235006635), Rossi, G. [Sejong U.], Sanchez, E. [Madrid, CIEMAT] (ORCID:0000000296468198), Schlegel, D. [LBL, Berkeley], Schubnell, M. [Michigan U.; KEK, Tsukuba; Hiroshima Shudo U.], Seo, H. [Ohio U., Athens] (ORCID:0000000265883508), Silber, J. [LBL, Berkeley] (ORCID:0000000234610320), Sinigaglia, F. [Laguna U., Tenerife; IAC, La Laguna] (ORCID:0000000206398043), Sprayberry, D. [Natl. Solar Observ., Tucson], Tan, T. [IRFU, Saclay] (ORCID:0000000182891481), Tarlé, G. [Michigan U.; KEK, Tsukuba; Hiroshima Shudo U.] (ORCID:0000000317040781), Walther, M. [Munich, Tech. U., Universe; Munich U.] (ORCID:0000000217483745), Weaver, B. A. [Natl. Solar Observ., Tucson], Yèche, C. [IRFU, Saclay] (ORCID:0000000151468533), Zhou, R. [LBL, Berkeley] (ORCID:0000000153814372), Zou, H. [Beijing Observ.] (ORCID:0000000266843997). 2025-09-18. DESI DR1 Ly$α$ forest: 3D full-shape analysis and cosmological constraints. https://www.osti.gov/biblio/2997659
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