Using Voids to Unscreen Modified Gravity

Falck, Bridget; Koyama, Kazuya; Zhao, Gong-Bo; Cautun, Marius

Abstract

The Vainshtein mechanism, present in many models of gravity, is very effective at screening dark matter halos such that the fifth force is negligible and general relativity is recovered within their Vainshtein radii. Vainshtein screening is independent of halo mass and environment, in contrast to e.g. chameleon screening, making it difficult to test. However, our previous studies have found that the dark matter particles in filaments, walls, and voids are not screened by the Vainshtein mechanism. We therefore investigate whether cosmic voids, identified as local density minima using a watershed technique, can be used to test models of gravity that exhibit Vainshtein screening. We measure density, velocity, and screening profiles of stacked voids in cosmological N-body simulations using both dark matter particles and dark matter halos as tracers of the density field. We find that the voids are completely unscreened, and the tangential velocity and velocity dispersion profiles of stacked voids show a clear deviation from ΛCDM at all radii. Voids have the potential to provide a powerful test of gravity on cosmological scales.

Citation

Falck, B., Koyama, K., Zhao, G., & Cautun, M. (2018). Using Voids to Unscreen Modified Gravity. Monthly Notices of the Royal Astronomical Society, 475(3), 3262-3272. https://doi.org/10.1093/mnras/stx3288

• Journal Article Type: Article
• Acceptance Date: Dec 15, 2017
• Online Publication Date: Dec 22, 2017
• Publication Date: Apr 11, 2018
• Deposit Date: Jan 2, 2018
• Publicly Available Date: Jan 3, 2018
• 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: 475
• Issue: 3
• Pages: 3262-3272
• DOI: https://doi.org/10.1093/mnras/stx3288
• Public URL: https://durham-repository.worktribe.com/output/1369388