Multiple non-spherical structures from the extrema of Szekeres scalars

TL;DR

This paper analyzes the extrema of covariant scalars in Szekeres dust models, providing conditions for multiple extrema distributions that evolve without singularities, enabling detailed relativistic modeling of cosmic structures.

Contribution

It introduces conditions for multiple extrema in Szekeres models that evolve smoothly, facilitating realistic modeling of cosmic structures from initial conditions.

Findings

Existence of multiple extrema distributions in Szekeres models.

Stable evolution of these extrema without shell crossing singularities.

Potential for detailed relativistic modeling of cosmic structures.

Abstract

We examine the spatial extrema (local maxima, minima and saddle points) of the covariant scalars (density, Hubble expansion, spatial curvature and eigenvalues of the shear and electric Weyl tensors) of the quasi-spherical Szekeres dust models. Sufficient conditions are obtained for the existence of distributions of multiple extrema in spatial comoving locations that can be prescribed through initial conditions. These distributions evolve without shell crossing singularities at least for ever expanding models (with or without cosmological constant) in the full evolution range where the models are valid. By considering the local maxima and minima of the density, our results allow for setting up elaborated networks of "pancake" shaped evolving cold dark matter over-densities and density voids whose spatial distribution and amplitudes can be controlled from initial data compatible with standard early Universe initial conditions. We believe that these results have an enormous range of potential application by providing a fully relativistic non-perturbative coarse grained modelling of cosmic structure at all scales.