Collisionless Dynamics and the Cosmic Web

TL;DR

This paper reviews the role of the Zeldovich approximation in understanding the hierarchical formation of cosmic structures, discusses classifications of large-scale structure, and explores new tessellation-based methods for analyzing dark matter dynamics.

Contribution

It introduces novel tessellation-based approaches to analyze the non-linear regime of collisionless dark matter dynamics, enhancing information extraction from simulations.

Findings

Hierarchical structure formation from voids to halos

Classification of cosmic structures using modified Zeldovich approximations

Development of tessellation methods for detailed dark matter analysis

Abstract

I review the nature of three-dimensional collapse in the Zeldovich approximation, how it relates to the underlying nature of the three-dimensional Lagrangian manifold and naturally gives rise to a hierarchical structure formation scenario that progresses through collapse from voids to pancakes, filaments and then halos. I then discuss how variations of the Zeldovich approximation (based on the gravitational or the velocity potential) have been used to define classifications of the cosmic large-scale structure into dynamically distinct parts. Finally, I turn to recent efforts to devise new approaches relying on tessellations of the Lagrangian manifold to follow the fine-grained dynamics of the dark matter fluid into the highly non-linear regime and both extract the maximum amount of information from existing simulations as well as devise new simulation techniques for cold collisionless dynamics.