Validation of the DESI DR2 Lyα BAO analysis using synthetic datasets

Journal article

The second data release (DR2) of the Dark Energy Spectroscopic Instrument (DESI), containing data from the first three years of observations, doubles the number of Lyman-α (Lyα) forest spectra in DR1 and it provides the largest dataset of its kind. To ensure a robust validation of the baryonic acoustic oscillation (BAO) analysis using Lyα forests, we have made significant updates compared to DR1 to both the mocks and the analysis framework used in the validation. In particular, we present CoLoRe-QL, a new set of Lyα mocks that use a quasilinear input power spectrum to incorporate the nonlinear broadening of the BAO peak. We have also increased the number of realizations used in the validation to 400, compared to the 150 realizations used in DR1. Finally, we present a detailed study of the impact of quasar redshift errors on the BAO measurement, and we compare different strategies to mask damped Lyman-α absorbers in our spectra. The BAO measurement from the Lyα dataset of DESI DR2 is presented in a companion publication.

Authors: Casas, L; Herrera-Alcantar, HK; Chaves-Montero, J; Cuceu, A; Font-Ribera, A

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Physical Society
• Journal: Physical Review D (particles, fields, gravitation, and cosmology)
• Volume: 113
• Issue: 2
• Article number: 023520
• Publication date: 2026-01-16
• Acceptance date: 2025-12-10
• DOI: 10.1103/fvgh-kswf
• EISSN: 2470-0029
• ISSN: 2470-0010
• Language: English