Cosmological simulations with relativistic and primordial non-Gaussianity contributions as initial conditions [article]

Miguel Enríquez, Juan Carlos Hidalgo, Octavio Valenzuela
2021
We present a method to implement relativistic corrections to the evolution of dark matter structures in cosmological simulations of a ΛCDM universe. We take the non-linear correspondence between the Lagrangian (Newtonian) evolution of dark matter inhomogeneities and the synchronous-comoving (relativistic) matter density description, and use it to promote the relativistic constraint as the initial condition for numerical simulations of structure formation. In this method, the incorporation of
more » ... mordial non-Gaussianity (PNG) contributions as initial conditions is straightforward. We implement the relativistic, fNL and gNL contributions as initial conditions for the L-PICOLA code, and derive the power spectrum and bispectrum of the evolved matter field. We focus specifically in the case of largest values of non-Gaussianity allowed at 1σby Planck (fNL=-4.2 and gNL=-7000). As a checkup, we show consistency with the one-loop perturbative prescription in the adequate scales. Our results confirm that both relativistic and PNG features are most prominent at very large scales and for squeezed triangulations, but there is also a small relativistic effect at scales beyond the perturbative regime in the bispectrum. We discuss future prospects to probe these two contributions in the bispectrum of the matter density distribution.
doi:10.48550/arxiv.2109.13364 fatcat:jul3b45c75dyvnvt5k2q2lul7m