Modeling void abundance in modified gravity

Abstract

Reprinted with permission from the American Physical Society: Physical Review D, 95, 024018 c (2017) by the American Physical Society. Readers may view, browse, and/or download material for temporary copying purposes only, provided these uses are for noncommercial personal purposes. Except as provided by law, this material may not be further reproduced, distributed, transmitted, modied, adapted, performed, displayed, published, or sold in whole or part, without prior written permission from the American Physical Society.Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. We use a spherical model and an extended excursion set formalism with drifting diffusive barriers to predict the abundance of cosmic voids in the context of general relativity as well as fðRÞ and symmetron models of modified gravity. We detect spherical voids from a suite of N-body simulations of these gravity theories and compare the measured void abundance to theory predictions. We find that our model correctly describes the abundance of both dark matter and galaxy voids, providing a better fit than previous proposals in the literature based on static barriers. We use the simulation abundance results to fit for the abundance model free parameters as a function of modified gravity parameters, and show that counts of dark matter voids can provide interesting constraints on modified gravity. For galaxy voids, more closely related to optical observations, we find that constraining modified gravity from void abundance alone may be significantly more challenging. In the context of current and upcoming galaxy surveys, the combination of void and halo statistics including their abundances, profiles and correlations should be effective in distinguishing modified gravity models that display different screening mechanisms.

Cosmic voids in modified gravity scenarios

“…A.5. -As was shown by Voivodic et al (2017), the linear power spectrum is larger in MG at small scales. This effect translates into a matter correlation function that is also larger at intermediate and small scales in stronger MG cases.…”

“…In this section we present the phenomenological expressions we used to describe the void abundance f (σ), the void density profile ρ(r , r 0.2 ), and the void-matter linear bias b(σ). Here, σ 2 = σ 2 (R) is the variance of the linear matter power spectrum smoothed on a scale R, which was computed for the ΛCDM and MG cases as described in Voivodic et al (2017).…”

“…It has been shown (e.g., Voivodic et al 2017) that the abundance of spherical voids is well described by the excursion set formalism and parameters δ v and δ c that come from spherical expansion or collapse theories. The voids of Voivodic et al were grown centered on positions given by particle coordinates of the minimum of the density field given by the Voronoi volume of each particle.…”

“…The study of voids in the context of modified gravity has recently gained strength. This includes mainly the effect of MG on the void abundance Jennings et al 2013;Lam et al 2015;Cai et al 2015;Voivodic et al 2017) and in the lensing signature around voids Winther & Ferreira 2015;Baker et al 2018). In these scenarios, the galaxy distribution is modified by the fifth force associated with MG, and in turn, this also affects the shape and abundance of voids (Zivick et al 2015).…”

Non-linear phenomenology of disformally coupled quintessence

“…32 may be important in specific situations and thus cannot be taken by granted in general. This may be important in particular because voids and their outer limits, where ∇ · F Ψ approaches zero, were discussed in several opportunities as relevant probes of modified gravity (Llinares 2011;Cai et al 2015;Barreira et al 2015;Voivodic et al 2017;Falck et al 2018). An additional result that comes from Eq.…”