First Detection of the BAO Signal from Early DESI Data

We present the detection of the baryon acoustic oscillations (BAO) signal using unblinded data collected during the initial two months of operations of the Stage-IV ground-based Dark Energy Spectroscopic Instrument (DESI). From 261,291 Luminous Red Galaxies spanning redshifts 0.4 < z < 1.1 and 1651 sq. deg. with a 57.9% completeness, we report a 5σ level BAO detection at a precision of 1.7%. Using 630,480 Bright Galaxy Sample over 0.1 < z < 0.5, 3677 sq. deg. with a 50.0% completeness, we also detect the BAO feature at 3σ significance with a 2.6% precision. These are an important milestone which confirms the choice of the survey design, quality performance of the complex robotically-actuated, fiber-fed DESI spectrograph, validates the spectroscopic pipeline and data management system. Based on these first promising results, we forecast that DESI is on target to achieve a high-significance BAO detection at a sub-percent accuracy with the completed 5-year survey data, meeting the Level 1 science requirements on BAO measurement precision. This will set novel standards in cosmology, and confirm DESI as one of the most competitive Stage-IV BAO experiments for large-scale spectroscopic surveys for the remainder of this decade.