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GR: Fachverband Gravitation und Relativitätstheorie

GR 18: Cosmology

GR 18.1: Vortrag

Freitag, 23. März 2018, 09:20–09:40, Phys-SR-SE1

Turn back time: Gaussianising the late-time matter density field — •Cora Uhlemann — DAMTP, University of Cambridge

Since the matter distribution in the early universe is nearly perfectly Gaussian, one can extract almost all of the statistical information from the two-point correlation function of densities. However, the growth of structures over time causes significant deviations from Gaussianity which arise due to the nonlinear dynamics of gravitational clustering. This complicates the analysis of late-time observables such as the galaxy distribution extracted from large-scale structure surveys. I will explain how one can infer a gaussianising transformation from recent theoretical insights into the statistics of densities in spheres. This Gaussianisation maps the late-time density to an almost Gaussian field which is in better correspondence to the linear density field - hence essentially turns back time.