Character and detectability of the dark ages and the epoch of reionization: the view from the simulations

TL;DR

This paper reviews recent simulation-based findings on the characteristics and detectability of the Dark Ages and Epoch of Reionization signals with current and upcoming low-frequency radio telescopes, highlighting optimal observational strategies.

Contribution

It provides a comprehensive analysis of EOR signal properties and observability, comparing capabilities of major radio arrays based on recent simulations.

Findings

Optimal detection frequencies are 140-160 MHz.

EOR signals are strongly non-Gaussian at late times.

Foreground cleaning is aided by short correlation widths of 300-800 kHz.

Abstract

Direct detection of the Dark Ages and the Epoch of Reionization (EOR) is among the main scientific objectives of all current and future low-frequency radio facilities. In this paper we summarize and discuss recent results, based on state-of-the-art numerical simulations, regarding the fundamental EOR properties and its observability with current and future radio arrays, like the Giant Metrewave Radio Telescope (GMRT), the Low Frequency Array (LOFAR), the 21-CM Array (21CMA), the Murchison Widefield Array (MWA) and the Square Kilometre Array (SKA). Results show that the optimal observational frequencies for statistical detection are 140-160 MHz. The signals are strongly non-Gaussian at late times. The correlation widths between 21-cm maps at neighbouring frequencies are short, of order 300-800 kHz, which should help with the cleaning of the strong foregrounds. Direct comparison of the resolutions and expected sensitivities of GMRT and MWA indicate that their optimal sensitivity ranges are similar, at scales k~0.2-0.4 h/Mpc, however, all else being equal the former should require shorter integration times due to its significantly larger collecting area.