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The e-MANTIS emulator: fast predictions of the non-linear matter power spectrum in f(R)CDM cosmology

Sáez-Casares, Iñigo; Rasera, Yann; Li, Baojiu

The e-MANTIS emulator: fast predictions of the non-linear matter power spectrum in f(R)CDM cosmology Thumbnail


Authors

Iñigo Sáez-Casares

Yann Rasera



Abstract

In order to probe modifications of gravity at cosmological scales, one needs accurate theoretical predictions. N-body simulations
are required to explore the non-linear regime of structure formation but are very time consuming. In this work, we release a new
public emulator, dubbed E-MANTIS, that performs an accurate and fast interpolation between the predictions of f(R) modified
gravity cosmological simulations, run with ECOSMOG. We sample a wide 3D parameter space given by the current background
scalar field value 10−7 < fR0 < 10−4, matter density 0.24 < m < 0.39, and primordial power spectrum normalization 0.6 < σ8 < 1.0, with 110 points sampled from a Latin hypercube. For each model we perform pairs of f(R)CDM and CDM simulations covering an effective volume of 560 h−1 Mpc3 with a mass resolution of ∼2 × 1010h−1M. We build an emulator for the matter power spectrum boost B(k) = Pf(R)(k)/PCDM(k) using a Gaussian process regression method. The boost is mostly independent of h, ns, and b, which reduces the dimensionality of the relevant cosmological parameter space. Additionally, it is more robust against statistical and systematic errors than the raw power spectrum, thus strongly reducing our computational needs. According to our dedicated study of numerical systematics, the resulting emulator has an estimated maximum error of 3 per cent across the whole cosmological parameter space, for scales 0.03 h Mpc−1 <k< 7 h Mpc−1, and redshifts 0 <z< 2, while in most cases the accuracy is better than 1 per cent. Such an emulator could be used to constrain f(R) gravity with weak lensing analyses.

Citation

Sáez-Casares, I., Rasera, Y., & Li, B. (2024). The e-MANTIS emulator: fast predictions of the non-linear matter power spectrum in f(R)CDM cosmology. Monthly Notices of the Royal Astronomical Society, 527(3), 7242-7262. https://doi.org/10.1093/mnras/stad3343

Journal Article Type Article
Acceptance Date Oct 25, 2023
Online Publication Date Nov 2, 2023
Publication Date 2024-01
Deposit Date Mar 28, 2024
Publicly Available Date Mar 28, 2024
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 527
Issue 3
Pages 7242-7262
DOI https://doi.org/10.1093/mnras/stad3343
Keywords Space and Planetary Science; Astronomy and Astrophysics
Public URL https://durham-repository.worktribe.com/output/2349590

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Licence
http://creativecommons.org/licenses/by/4.0/

Publisher Licence URL
http://creativecommons.org/licenses/by/4.0/

Copyright Statement
© The Author(s) 2023.
Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium,
provided the original work is properly cited.





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