Physics of non-Gaussian fields and the cosmological genus statistic

We report a technique to calculate the impact of distinct physical processes inducing non-Gaussianity on the cosmological density field. A natural decomposition of the cosmic genus statistic into an orthogonal polynomial sequence allows complete expression of the scale-dependent evolution of the mor...

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Bibliographic Details
Published in:arXiv.org 2012-05
Main Author: James, J Berian
Format: Article
Language:English
Subjects:
Astronomical catalogs
Decomposition
Deformation
Galactic evolution
Galaxies
Large scale structure of the universe
Mathematical morphology
Polynomials
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Summary:We report a technique to calculate the impact of distinct physical processes inducing non-Gaussianity on the cosmological density field. A natural decomposition of the cosmic genus statistic into an orthogonal polynomial sequence allows complete expression of the scale-dependent evolution of the morphology of large-scale structure, in which effects including galaxy bias, nonlinear gravitational evolution and primordial non-Gaussianity may be delineated. The relationship of this decomposition to previous methods for analysing the genus statistic is briefly considered and the following applications are made: i) the expression of certain systematics affecting topological measurements; ii) the quantification of broad deformations from Gaussianity that appear in the genus statistic as measured in the Horizon Run simulation; iii) the study of the evolution of the genus curve for simulations with primordial non-Gaussianity. These advances improve the treatment of flux-limited galaxy catalogues for use with this measurement and further the use of the genus statistic as a tool for exploring non-Gaussianity.
ISSN:2331-8422
DOI:10.48550/arxiv.1111.1794