Dark Energy Survey year 1 results: Cosmological constraints from galaxy clustering and weak lensing

Abstract

We present cosmological results from a combined analysis of galaxy clustering and weak gravitational lensing, using 1321 deg 2 of griz imaging data from the first year of the Dark Energy Survey (DES Y1). We combine three two-point functions: (i) the cosmic shear correlation function of 26 million source galaxies in four redshift bins, (ii) the galaxy angular autocorrelation function of 650,000 luminous red galaxies in five redshift bins, and (iii) the galaxy-shear cross-correlation of luminous red galaxy positions and source galaxy shears. To demonstrate the robustness of these results, we use independent pairs of galaxy shape, photometric redshift estimation and validation, and likelihood analysis pipelines. To prevent confirmation bias, the bulk of the analysis was carried out while "blind" to the true results; we describe an extensive suite of systematics checks performed and passed during this blinded phase. The data are modeled in flat ΛCDM and wCDM cosmologies, marginalizing over 20 nuisance parameters, varying 6 (for ΛCDM) or 7 (for wCDM) cosmological parameters including the neutrino mass density and including the 457 × 457 element analytic covariance matrix. We find consistent cosmological results from these three two-point functions, and from their combination obtain S8 ≡ σ8(Ωm/0.3) 0.5 = 0.773 +0.026 −0.020 and Ωm = 0.267 +0.030 −0.017 for ΛCDM; for wCDM, we find S8 = 0.782 +0.036 −0.024 , Ωm = 0.284 +0.033 −0.030 , and w = −0.82 +0.

Status of Neutrino Properties and Future Prospects—Cosmological and Astrophysical Constraints

“…In particular, one can define the free-streaming length at time t as the distance that neutrinos can travel from decoupling until t. The comoving free-streaming length reaches a maximum at the time of the non-relativistic transition. This corresponds to a critical wavenumber k fs , given in equation (27) for transitions happening during matter-domination, above which perturbations in the neutrino component are erased.…”

“…WL for row no. 10 is the combination of galaxy, shear and galaxy-galaxy lensing spectra from DES Year1 [27]. SZ in row no.…”

“…BAO for row no. 9-10 are from 6dFGS [100], SDSS MGS [104], BOSS DR12 [23] (see [27] for details). BAO data for row no.…”

“…The most recent weak lensing datasets have been released by the Kilo-Degree Survey (KiDS [26,118]) and the Dark Energy Survey (DES [27,119]). It is interesting to note that all of the aforementioned datasets provide results in terms of cosmological parameters which are slightly in tension with the corresponding estimates coming from CMB data (which we remind is a highredshift probe).…”

“…Extended catalogs of galaxy clusters have been completed from several surveys (see e.g., [24] and references therein). In addition, weak lensing surveys (Canada-FranceHawaii Telescope Lensing Survey [25], Kilo-Degree Survey [26], Dark Energy Survey [27]) are mature enough to provide constraints on cosmological parameters that are competitive with those from other observables. They also allow to test the validity of the standard cosmological paradigm by comparing results obtained from high-redshift observables to those coming from measurements of the low-redshift universe.…”