We measure the angular BAO feature from the clustering of 16 million galaxies from the Dark Energy Survey with a significance of 3.5σ. For that, we use three different techniques: the angular correlation function, the angular power spectrum and the projected correlation function.
We used an optimised sample (see below) for this science case with an effective redshift of z=0.85, and splitted into 6 tomographic redshift bins. We consider three different redshift calibrations. We validate our analysis with 2000 simulations. Our BAO measurement sets the ratio of the angular distance (at z=0.85) to the sound horizon scale with a precision of 2.1%, which is found 4.3% and 2.1σ below the prediction of Planck-LCDM cosmology.
Dark Energy Survey: Galaxy sample for the baryonic acoustic oscillation measurement from the final dataset J. Mena-Fernández et al. | Corresponding author: menafernandez@cppm.in2p3.fr Link
This work looks for an optimal sample for running a BAO analysis. For that, we establish a magnitude cut in band i which linearly depends on redshift (i<a+bz). Balancing the number density versus the precision in redshifts, we find an optimal sample a=19.64 and b=2.894. We also impose a limit of i<22.5 for easier redshift validation. We study three different redshift calibration methods: DNF, direct calibration with VIPERS and clustering redshifts. Finally, we compute and validate the clustering weights to correct for astrophysical contaminants and varying survey conditions.
Dark Energy Survey: implications for cosmological expansion models from the final DES Baryon Acoustic Oscillation and Supernova data
DES Collaboration et al. | Corresponding Author: des-publication-queries@fnal.gov
After the release of the final BAO and final SN, we study their combined cosmology of these two background cosmology probes. We also combine our probes with CMB from Planck, and other background probes such as Big Bang Nucleosynthesis. In general, we find it difficult to reconcile all the measurements in the standard cosmological model, 𝝠CDM, but also when including free curvature, or freeing the equation of state of dark energy, finding several ~2-3σ tensions. Only in w0waCDM, when allowing the equation of state to vary with time, we obtain fully consistent results across probes. In this model, results lie in the w0>-1 wa<0 quadrant, finding a deviation of ~3σ from the 𝝠CDM case.
Dark Energy Survey: DESI-Independent Angular BAO Measurement
Both DES BAO and DESI BAO had shown some level of preference for w0waCDM when combined with DES SN and Planck CMB. When combined, this preference is stronger; however, they have some area of overlap, possibly duplicating some information. To avoid that, in this work, we exclude the area of overlap in the DES BAO measurement and combine it with DESI BAO. We also update the constraints with the more recent DES-Dovekie calibration and DESI-DR2. The combination of DES BAO, DESI-DR2 BAO, DES-Dovikie SN and Planck CMB yields a 3.1σ deviation from 𝝠CDM.
Year 3 BAO Results
Dark Energy Survey Year 3 Results: A 2.7% measurement of Baryon Acoustic Oscillation distance scale at redshift 0.835
