Quantifying Density-Ionization Correlations with the 21cm Power Spectrum

Abstract

The Epoch of Reionization (EoR)---when neutral hydrogen in the intergalactic medium was systematically ionized---is a period in our Universe's history that is currently poorly understood. However, a key prediction of most models is a correlation between the density and ionization field during the EoR. This has consequences for the 21cm power spectrum. Here, we propose a parametrization for the density-ionization correlation and study the dependence of the 21cm power spectrum on this parameterization. We use this formalism to forecast the ability of current and future observations to constrain these correlations. We find that upper limits on the dimensionless power spectrum at redshifts $7.5<z<8.5$ using $k$ bins between $0.1{\text{Mpc}}^{-1}<k<0.75{\text{Mpc}}^{-1}$ with error bars at the level of $\sim 20{\text{mK}}^2$ about our fiducial model would rule out uncorrelated reionization at $99\%$ credibility. Beyond upper limits, we find that at its full sensitivity, the Hydrogen Epoch of Reionization Array (HERA) will be able to place strong constraints on the sign and magnitude of density-ionization correlations.

12 pages, 10 figures. Replaced to match accepted MNRAS version; added Figure 9 for Section 5.3; no qualitative changes to results. References updated

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Cited by in corpus (12)

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• Machine-learning recovery of foreground wedge-removed 21-cm light cones for high-$z$ galaxy mapping
• Forecasts and Statistical Insights for Line Intensity Mapping Cross-Correlations: A Case Study with 21cm x [CII]
• Persistent topology of the reionization bubble network. II: Evolution & Classification
• A galaxy-free phenomenological model for the 21-cm power spectrum during reionization
• Probing the intergalactic medium during the Epoch of Reionization using 21-cm signal power spectra
• Using the sample variance of 21cm maps as a tracer of the ionisation topology
• Lyman Alpha Emitters and the 21cm Power Spectrum as Probes of Density-Ionization Correlation in the Epoch of Reionization
• Topology of Reionisation times: concepts, measurements and comparisons to gaussian random field predictions
• Reionisation time fields reconstruction from 21 cm signal maps
• Reionization Parameter Inference from 3D Minkowski Functionals of the 21 cm Signals