Models of the Cosmological 21 cm Signal from the Epoch of Reionization Calibrated with Lyman-alpha and CMB Data

Abstract

We present here 21 cm predictions from high dynamic range simulations for a range of reionization histories that have been tested against available Lyman-alpha and CMB data. We assess the observability of the predicted spatial 21 cm fluctuations by ongoing and upcoming experiments in the late stages of reionization in the limit in which the hydrogen spin temperature is significantly larger than the CMB temperature. Models consistent with the available Lyman-alpha data and CMB measurement of the Thomson optical depth predict typical values of 10--20 mK^2 for the variance of the 21 cm brightness temperature at redshifts z=7--10 at scales accessible to ongoing and upcoming experiments (k < 1 h/cMpc). This is only a factor of a few below the sensitivity claimed to have been already reached by ongoing experiments in the signal rms value. Our different models for the reionization history make markedly different predictions for the redshift evolution and thus frequency dependence of the 21 cm power spectrum and should be easily discernible by LOFAR (and later HERA and SKA1) at their design sensitivity. Our simulations have sufficient resolution to assess the effect of high-density Lyman limit systems that can self-shield against ionizing radiation and stay 21 cm bright even if the hydrogen in their surroundings is highly ionized. Our simulations predict that including the effect of the self-shielded gas in highly ionized regions reduces the large scale 21 cm power by about 30%.

18 pages, 13 figures; matches version accepted in MNRAS

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Cited by in corpus (13)

• Introducing the THESAN project: radiation-magnetohydrodynamic simulations of the epoch of reionization
• Feedback-regulated star formation and escape of LyC photons from mini-haloes during reionisation
• Relativistic N-body simulations with massive neutrinos
• The short ionizing photon mean free path at z=6 in Cosmic Dawn III, a new fully-coupled radiation-hydrodynamical simulation of the Epoch of Reionization
• Modelling the observed luminosity function and clustering evolution of Lyman-$\alpha$ emitters: growing evidence for late reionization
• Epoch of Reionisation 21cm Forecasting From MCMC-Constrained Semi-Numerical Models
• Revised estimates of CMB $B$-mode polarization induced by patchy reionization
• Late-end reionization with ATON-HE: towards constraints from Lyman-$\alpha$ emitters observed with JWST
• Synergizing 21 cm and sub-millimetre surveys during reionization: new empirical insights
• Estimation of HII Bubble Size Distribution from 21cm Power Spectrum with Artificial Neural Networks
• Estimating the Feasibility of 21cm-Ly$\alpha$ Synergies using the Hydrogen Epoch of Reionization Array
• The impact of faint AGN discovered by JWST on reionization
• Studying neutral hydrogen structures during the epoch of reionization using fractal dimensions