Cosmological N-body simulations with a large-scale tidal field. Issue 1 (1st June 2018)

• Record Type: Journal Article
• Authors: Schmidt, Andreas S; White, Simon D M; Schmidt, Fabian; Stücker, Jens
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 479:Issue 1(2018)
• Page Start: 162
• Page End: 170
• Publication Date: 2018-06-01
• Subjects: methods: numerical -- large-scale structure of Universe; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/sty1430
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: In this paper we carry out anisotropic 'separate universe' simulations by including a large-scale tidal field in the N -body code gadget 4 using an anisotropic expansion factor Aij . We use the code in a pure particle-mesh mode to simulate the evolution of 16 realizations of an initial density field with and without a large-scale tidal field, which are then used to measure the response function describing how the tidal field influences structure formation in the linear and non-linear regimes. Together with the previously measured response to a large scale overdensity, this completely describes the non-linear matter bispectrum in the squeezed limit. We find that, contrary to the density response, the tidal response never significantly exceeds the large-scale perturbation-theory prediction even on non-linear scales for the redshift range we discuss. We develop a simple halo model that takes into account the effect of the tidal field and compare it with our direct measurement from the anisotropic N -body simulations.