UK Cosmo, NAM 2014, Portsmouth

Abstract:

Screening mechanisms allow modified gravity theories to meet stringent constraints from solar system tests of gravity while allowing the low-density or large scale behavior to produce accelerated expansion. Unlike chameleon and symmetron screening, which come into effect in regions of high density, Vainshtein screening instead depends on the dimensionality of the system, and screened bodies can still feel external fields. This suggests that instead of depending on local environmental density, the Vainshtein mechanism may relate to the cosmic web of large scale structure, containing halos, voids, one-dimensional filaments, and two-dimensional walls. The ORIGAMI method of identifying the features of the cosmic web in simulations is well-suited to this problem because it defines morphologies according to the dimensionality of the collapsing structure, and it does not depend on a smoothing scale or density threshold parameter.  In this talk I will describe the ORIGAMI method and our Vainshtein simulations, and I will present results on the morphological dependence of the Vainshtein mechanism for both dark matter particles and halos.