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DES Y3 cosmic shear down to small scales: constraints on cosmology and baryons
Speaker
Giaovanni Aricò ICS, University of Zürich (Zürich, Switzerland)
Abstract
In this seminar, I will present a reanalysis of DES Y3 cosmic shear data, which, for the first time, includes all angular scales measured. I will introduce the theoretical model used, BACCOemu, which relies on a combination of N-body simulations, physical models of baryonic processes, and neural networks. I will discuss how the additional data produce cosmological parameters that are tighter but consistent with those obtained from larger scales, while also constraining the distribution of baryons. Our constraint on S8 is statistically compatible with the value inferred from the data collected by the Planck satellite, with a confidence level of 0.9σ. However, we observe a shift of 1.4σ compared to the results of the official DES Y3 cosmic shear analysis, which can be attributed to different modelling choices regarding intrinsic alignment, non-linearities, baryons, and lensing shear ratios. We conclude that small scales in cosmic shear data contain valuable astrophysical and cosmological information and thus should be included in standard analyses.
Date and Time
October 5 2023 4pm KST (= 7am UTC) Zoom link (active once the seminar starts)