Cosmic Reionization on Computers: Evolution of the Flux Power Spectrum

TL;DR

This paper investigates how the flux power spectrum evolves during cosmic reionization using CROC simulations, revealing that its shape remains stable while its amplitude correlates strongly with reionization timing, enabling potential future measurements.

Contribution

It demonstrates that the flux power spectrum's shape is insensitive to reionization timing, but its amplitude evolution correlates with reionization, offering a new way to estimate reionization redshift.

Findings

Flux power spectrum shape is insensitive to reionization timing.

Amplitude of flux power spectrum strongly correlates with reionization timing.

Potential for future measurements to determine reionization redshift.

Abstract

We explore the evolution of the flux power spectrum in the Cosmic Reionization On Computers (CROC) simulations. We find that, contrary to some previous studies, the shape of the flux power spectrum is rather insensitive to the timing of reionization. However, the amplitude of the flux power spectrum does strongly evolve with time, and that evolution is almost perfectly correlated with the timing of reionization. We show how such correlation can be used in a (futuristic) measurement to determine the redshift of overlap of ionized bubbles.