Combined tracer analysis for DESI 2024 BAO

arXiv:2508.05467 · astro-ph.CO · Submitted 2025-08-07 · Read on arXiv

astro-ph.CO

Submitted: 2025-08-07

Updated: 2026-09-14

Comments: This DESI Publication is part of the 2024 series using the first year of observations (see https://data.desi.lbl.gov/doc/papers/). 36 pages, 9 figures. Updated to match the published version. The supplementary data is available at https://zenodo.org/records/19561326

Journal ref: JCAP 04 (2026) 058

DOI: 10.1088/1475-7516/2026/04/058

Code: https://github.com/cosmodesi/pycorrhttps:

License: http://creativecommons.org/licenses/by/4.0/

The gist: This paper demonstrates how the Dark Energy Spectroscopic Instrument (DESI) Data Release 1 (DR1) and future baryon acoustic oscillations (BAO) analyses can optimally combine overlapping tracers

Terminology

Abstract

This paper demonstrates how the Dark Energy Spectroscopic Instrument (DESI) Data Release 1 (DR1) and future baryon acoustic oscillations (BAO) analyses can optimally combine overlapping tracers (galaxies of distinct types) in the same redshift range. We make a unified catalog of Luminous Red Galaxies (LRGs) and Emission Line Galaxies (ELGs) in the redshift range 0.8 < z < 1.1 and investigate the impact on the BAO constraints. DESI DR1 contains 30% of the final DESI LRG sample and less than 25% of the final ELG sample, and the combination of LRGs and ELGs increases the number density and reduces the shot noise. We developed a pipeline to merge the overlapping tracers using galaxy bias as an approximately optimal weight and tested the pipeline on a suite of Abacus simulations, calibrated on the final version of the DESI Early Data Release. When applying our pipeline to the DESI DR1 catalog, we find an improvement in the BAO constraints of 11% for α iso and 7.0% for α AP consistent with our findings in mock catalogs. Our analysis was integrated into the DESI DR1 BAO analysis to produce the LRG+ELG result in the 0.8 < z < 1.1 redshift bin, which provided the most precise BAO measurement from DESI DR1 with a 0.86% constraint on the BAO distance scale and a 9.1σ detection of the isotropic BAO feature.

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