Session F01: First Year Results from the Dark Energy Spectroscopic Instrument (DESI)

The Dark Energy Spectroscopic Instrument First Year Results: Baryon Acoustic Oscillations from Galaxies and Quasars at z <2

The Dark Energy Spectroscopic Instrument (DESI) collaboration is conducting a five-year redshift survey of 40 million extra-galactic sources over 14,000 square degrees of the northern sky up to the redshift of 4 with the Mayall 4-meter telescope at Kitt Peak National Laboratory. One of its primary goals is to measure the cosmic expansion history precisely and accurately through the measurements of baryon acoustic oscillations (BAO). In this talk, I will present the unblinded measurements of DESI First Year  Baryon Acoustic Oscillations using the distributions of galaxies and quasars over the redshift range of 0.1-2 and the estimates of the relevant systematics. For the first time, we employed catalog-level blinding in the BAO analysis to prevent confirmation bias in determining the expansion history. The resultant aggregate precision of DESI Year 1 BAO surpasses that of all previous galaxy surveys combined prior to DESI.   

The Dark Energy Spectroscopic Instrument First Year Results: Baryon Acoustic Oscillations in the Lyman-alpha Forests of High Redshift Quasars

The Dark Energy Spectroscopic Instrument (DESI) collaboration is conducting a 5 year redshift survey of 40 million extra-galactic sources over 14,000 square degrees of the northern sky. One of its primary goals is to measure the cosmic expansion history with baryon acoustic oscillations (BAO). We present the measurement of BAO in the Lyman-alpha forests of high redshift quasars from the DESI first year data set, using the two-point correlation function of about 450,000 Lyman-alpha forest spectra and their correlation with the position of about 700,000 quasars. The analysis was developed on a blinded data set, and was un-blinded only after verifying the accuracy of the method with synthetic data, and the consistency of the results with several data splits and variations in the analysis choices. We obtain the most precise measurement to date of the angular diameter and Hubble distances relative to the sound horizon at recombination in the redshift range 2 to 4, with an aggregate isotropic precision of 1.1 percent at an effective redshift of 2.34.   

The Dark Energy Spectroscopic Instrument First Year Results: Cosmological Parameters from the Baryon Acoustic Oscillations

The Dark Energy Spectroscopic Instrument (DESI) collaboration is conducting a five year redshift survey of 40 million extra-galactic sources over 14,000 square degrees of the northern sky. Its primary goals are to measure the cosmic expansion history with Baryon Acoustic Oscillations (BAO) and the growth rate of structure with Redshift Space Distortions (RSD) . We will present for the first time cosmology results from DESI year-1 data for the expansion history derived from precise measurements of the Baryon Acoustic Oscillations (BAO). The results particularly include new stringent constraints on the dark energy equation of state, the Hubble parameter, spatial curvature, and neutrino mass from DESI data with and without various other available cosmological data sets. The cosmological implications of the results will be briefly discussed.