Authors

Abstract

We present cosmological constraints from the analysis of angular power spectra of cosmicshear maps based on data from the first three years of observations by the Dark Energy Survey (DES Y3). The shape catalog contains ellipticity measurements for over 100 million galaxies within a footprint of 4143 square degrees. Our measurements are based on the pseudo- method and offer a view complementary to that of the two-point correlation functions in real space, as the two estimators are known to compress and select Gaussian information in different ways, due to scale cuts. They may also be differently affected by systematic effects and theoretical uncertainties, such as baryons and intrinsic alignments (IA), making this analysis an important cross-check. In the context of CDM, and using the same fiducial model as in the DES Y3 real space analysis, we find 8 8 m/0.3 = 0.793+0.038 0.025, which further improves to 8 = 0.784 0.026 when including shear ratios. This constraint is within expected statistical fluctuations from the real space analysis, and in agreement with DES Y3 analyses of non-Gaussian statistics, but favors a slightly higher value of 8, which reduces the tension with the Planck cosmic microwave background 2018 results from 2.3 in the real space analysis to 1.5 in this work. We explore less conservative IA models than the one adopted in our fiducial analysis, finding no clear preference for a more complex model. We also include small scales, using an increased Fourier mode cut-off up to max = 5 h Mpc1, which allows to constrain baryonic feedback while leaving cosmological constraints essentially unchanged. Finally, we present an approximate reconstruction of the linear matter power spectrum at present time, which is found to be about 20% lower than predicted by Planck 2018, as reflected by the 1.5 lower 8 value.