paper

On the use of semi-numerical simulations in predicting the 21-cm signal from the epoch of reionization

arXiv:1403.0941 · doi:10.1093/mnras/stu1342

Abstract

We present a detailed comparison of three different simulations of the epoch of reionization (EoR). The radiative transfer simulation (-RAY) among them is our benchmark. Radiative transfer codes can produce realistic results, but are computationally expensive. We compare it with two semi-numerical techniques: one using the same halos as -RAY as its sources (Sem-Num), and one using a conditional Press-Schechter scheme (CPS+GS). These are vastly more computationally efficient than -RAY, but use more simplistic physical assumptions. We evaluate these simulations in terms of their ability to reproduce the history and morphology of reionization. We find that both Sem-Num and CPS+GS can produce an ionization history and morphology that is very close to -RAY, with Sem-Num performing slightly better compared to CPS+GS. We also study different redshift space observables of the 21-cm signal from EoR: the variance, power spectrum and its various angular multipole moments. We find that both semi-numerical models perform reasonably well in predicting these observables at length scales relevant for present and future experiments. However, Sem-Num performs slightly better than CPS+GS in producing the reionization history, which is necessary for interpreting the future observations.

20 pages, 14 figures, 1 table. Accepted for publication in MNRAS. Replaced to match the accepted version

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