Epoch of Reionization modelling and simulations for SKA

TL;DR

This paper reviews current simulation and modelling techniques for the Cosmic Dawn and Epoch of Reionization, emphasizing their physical processes, computational challenges, and the development of semi-analytical methods for efficient data interpretation.

Contribution

It provides a comprehensive overview of the state-of-the-art in reionization modelling, highlighting the integration of physical processes, computational strategies, and hybrid approaches for SKA data analysis.

Findings

Current simulations include key physical processes and reach required scales.

Semi-analytical methods can efficiently explore parameter space.

Hybrid models enable large libraries for observational interpretation.

Abstract

In this chapter we provide an overview of the current status of the simulations and modelling of the Cosmic Dawn and Epoch of Reionization. We discuss the modelling requirements as dictated by the characteristic scales of the problem and the SKA instrumental properties and the planned survey parameters. Current simulations include most of the relevant physical processes. They can follow the full nonlinear dynamics and are now reaching the required scale and dynamic range, although small-scale physics still needs to be included at sub-grid level. However, despite a significant progress in developing novel numerical methods for efficient utilization of current hardware they remain quite computationally expensive. In response, a number of alternative approaches, particularly semi-analytical/semi-numerical methods, have been developed. While necessarily more approximate, if appropriately constructed and calibrated on simulations they could be used to quickly explore the vast parameter space available. Further work is still required on including some physical processes in both simulations and semi-analytical modelling. This hybrid approach of fast, approximate modelling calibrated on numerical simulations can then be used to construct large libraries of reionization models for reliable interpretation of the observational data.