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Voids in Modified Gravity Reloaded: Eulerian Void Assignment

Lam, T.Y.; Clampitt, J.; Cai, Y.; Li, B.

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T.Y. Lam

J. Clampitt

Y. Cai


We revisit the excursion set approach to calculate void abundances in chameleon-type modified gravity theories, which was previously studied by Clampitt, Cai & Li. We focus on properly accounting for the void-in-cloud effect, i.e. the growth of those voids sitting in overdense regions may be restricted by the evolution of their surroundings. This effect may change the distribution function of voids hence affect predictions on the differences between modified gravity (MG) and general relativity (GR). We show that the thin-shell approximation usually used to calculate the fifth force is qualitatively good but quantitatively inaccurate. Therefore, it is necessary to numerically solve the fifth force in both overdense and underdense regions. We then generalize the Eulerian-void-assignment method of Paranjape, Lam & Sheth to our modified gravity model. We implement this method in our Monte Carlo simulations and compare its results with the original Lagrangian methods. We find that the abundances of small voids are significantly reduced in both MG and GR due to the restriction of environments. However, the change in void abundances for the range of void radii of interest for both models is similar. Therefore, the difference between models remains similar to the results from the Lagrangian method, especially if correlated steps of the random walks are used. As Clampitt et al., we find that the void abundance is much more sensitive to MG than halo abundances. Our method can then be a faster alternative to N-body simulations for studying the qualitative behaviour of a broad class of theories. We also discuss the limitations and other practical issues associated with its applications.


Lam, T., Clampitt, J., Cai, Y., & Li, B. (2015). Voids in Modified Gravity Reloaded: Eulerian Void Assignment. Monthly Notices of the Royal Astronomical Society, 450(3), 3319-3330.

Journal Article Type Article
Acceptance Date Apr 9, 2015
Publication Date Jul 1, 2015
Deposit Date Oct 2, 2014
Publicly Available Date Jun 29, 2015
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 450
Issue 3
Pages 3319-3330
Keywords Methods: numerical, Cosmology: theory, Dark energy, Large-scale structure of Universe.
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Published Journal Article (744 Kb)

Copyright Statement
This article has been accepted for publication in Monthly notices of the Royal Astronomical Society. ©: 2015 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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