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The matter density PDF for modified gravity and dark energy with Large Deviations Theory

Cataneo, Matteo; Uhlemann, Cora; Arnold, Christian; Gough, Alex; Li, Baojiu; Heymans, Catherine

The matter density PDF for modified gravity and dark energy with Large Deviations Theory Thumbnail


Authors

Matteo Cataneo

Cora Uhlemann

Christian Arnold

Alex Gough

Catherine Heymans



Abstract

We present an analytical description of the probability distribution function (PDF) of the smoothed 3D matter density field for modified gravity and dark energy. Our approach, based on the principles of Large Deviations Theory, is applicable to general extensions of the standard Lambda cold dark matter (ΛCDM) cosmology. We show that late-time changes to the law of gravity and background expansion can be included through Einstein-de Sitter spherical collapse dynamics combined with linear theory calculations and a calibration measurement of the non-linear variance of the smoothed density field from a simple numerical simulation. In a comparison to N-body simulations for f(R), DGP, and evolving dark energy theories, we find per cent level accuracy around the peak of the distribution for predictions in the mildly non-linear regime. A Fisher forecast of an idealized experiment with a Euclid-like survey volume demonstrates the power of combining measurements of the 3D matter PDF with the 3D matter power spectrum. This combination is shown to halve the uncertainty on parameters for an evolving dark energy model, relative to a power spectrum analysis on its own. The PDF is also found to substantially increase the detection significance for small departures from General Relativity, with improvements of up to six times compared to the power spectrum alone. This analysis is therefore very promising for future studies including non-Gaussian statistics, as it has the potential to alleviate the reliance of these analyses on expensive high-resolution simulations and emulators.

Journal Article Type Article
Acceptance Date Mar 26, 2022
Online Publication Date Apr 7, 2022
Publication Date 2022-06
Deposit Date Oct 27, 2021
Publicly Available Date Jun 8, 2022
Journal Monthly Notices of Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 513
Issue 2
Pages 1623-1641
DOI https://doi.org/10.1093/mnras/stac904
Public URL https://durham-repository.worktribe.com/output/1227819
Related Public URLs https://arxiv.org/abs/2109.02636

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Copyright Statement
This article has been accepted for publication in Monthly notices of the Royal Astronomical Society. ©: 2021 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.






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