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., Troxel, M. A., Yanny, B., Yin, B., Zhang, Y., Zuntz, J., Abbott, T. C., Aguena, M., Allam, S., Andrade-Oliveira, F., Bertin, E., Bocquet, S., Brooks, D., Burke, D. L., Carretero, J., Castander, F. J., Cawthon, R., Conselice, C., Costanzi, M., Pereira, M. S., Desai, S., Doel, P., Doux, C., Ferrero, I., Flaugher, B., Frieman, J., García-Bellido, J., Gutierrez, G., Herner, K., Hinton, S. R., Hollowood, D. L., Honscheid, K., James, D. J., Kuehn, K., Marshall, J. L., Mena-Fernández, J., Menanteau, F., Miquel, R., Ogando, R. C., Palmese, A., Paz-Chinchón, F., Pieres, A., Malagón, A. Plazas, Sanchez, E., Scarpine, V., Schubnell, M., Smith, M., Suchyta, E., Tarle, G., Thomas, D., To, C.
• Language: unknown
• Published: 2024
• Subjects: 79 ASTRONOMY AND ASTROPHYSICS; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; South pole
• Online Access: http://www.osti.gov/servlets/purl/2368750; https://www.osti.gov/biblio/2368750; https://doi.org/10.1093/mnras/stad2402

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 Ω m and the Hubble parameter h, $Ω_mh$ = ${0.915}_{-0.018}^{+0.023}$, and 2–3 per cent measurements of the amplitude of the galaxy clustering signals, probing galaxy bias and the amplitude of matter fluctuations, bσ 8 . 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.