The Dark Energy Survey Year 3 high-redshift sample: selection, characterization, and analysis of galaxy clustering

• Published in: Monthly Notices of the Royal Astronomical Society
• Main Authors: Sánchez, C, Alarcon, A, Bernstein, G M, Sanchez, J, Pandey, S, Raveri, M, Prat, J, Weaverdyck, N, Sevilla-Noarbe, I, Chang, C, Baxter, E, Omori, Y, Jain, B, Alves, O, Amon, A, Bechtol, K, Becker, M R, Blazek, J, Choi, A, Campos, A, Rosell, A Carnero, Kind, M Carrasco, Crocce, M, Cross, D, DeRose, J, Diehl, H T, Dodelson, S, Drlica-Wagner, A, Eckert, K, Eifler, T F, Elvin-Poole, J, Everett, S, Fang, X, Fosalba, P, Gruen, D, Gruendl, R A, Harrison, I, Hartley, W G, Huang, H, Huff, E M, Kuropatkin, N, MacCrann, N, McCullough, J, Myles, J, Krause, E, Porredon, A, Rodriguez-Monroy, M, Rykoff, E S, Secco, L F, Sheldon, E
• Other Authors: National Science Foundation, U.S. Department of Energy, Science and Technology Facilities Council, Higher Education Funding Council for England, Ohio State University, Financiadora de Estudos e Projetos, Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro
• Format: Article in Journal/Newspaper
• Language: English
• Published: Oxford University Press (OUP) 2023
• Subjects: Space and Planetary Science; Astronomy and Astrophysics; South Pole; Hubble; South pole
• Online Access: http://dx.doi.org/10.1093/mnras/stad2402; https://academic.oup.com/mnras/advance-article-pdf/doi/10.1093/mnras/stad2402/51142269/stad2402.pdf; https://academic.oup.com/mnras/article-pdf/525/3/3896/51389184/stad2402.pdf

ABSTRACT The fiducial cosmological analyses of imaging surveys like DES typically probe the Universe at redshifts z < 1. We present the selection and characterization of high-redshift galaxy samples using DES Year 3 data, and the analysis of their galaxy clustering measurements. In particular, we use galaxies that are fainter than those used in the previous DES Year 3 analyses and a Bayesian redshift scheme to define three tomographic bins with mean redshifts around z ∼ 0.9, 1.2, and 1.5, which extend the redshift coverage of the fiducial DES Year 3 analysis. These samples contain a total of about 9 million galaxies, and their galaxy density is more than 2 times higher than those in the DES Year 3 fiducial case. We characterize the redshift uncertainties of the samples, including the usage of various spectroscopic and high-quality redshift samples, and we develop a machine-learning method to correct for correlations between galaxy density and survey observing conditions. The analysis of galaxy clustering measurements, with a total signal to noise S/N ∼ 70 after scale cuts, yields robust cosmological constraints on a combination of the fraction of matter in the Universe Ωm and the Hubble parameter h, $\Omega _m h = 0.195^{+0.023}_{-0.018}$, and 2–3 per cent measurements of the amplitude of the galaxy clustering signals, probing galaxy bias and the amplitude of matter fluctuations, bσ8. A companion paper (in preparation) will present the cross-correlations of these high-z samples with cosmic microwave background lensing from Planck and South Pole Telescope, and the cosmological analysis of those measurements in combination with the galaxy clustering presented in this work.