Prediction of the 21-cm signal from reionization: comparison between 3D
  and 1D radiative transfer schemes
  Three-dimensional radiative transfer simulations of the epoch of reionization
can produce realistic results, but are computationally expensive. On the other
hand, simulations relying on one-dimensional radiative transfer solutions are
faster but limited in accuracy due to their more approximate nature. Here, we
compare the performance of the reionization simulation codes grizzly and C2-ray
which use 1D and 3D radiative transfer schemes respectively. The comparison is
performed using the same cosmological density fields, halo catalogues and
source properties. We find that the ionization maps, as well as the 21-cm
signal maps from these two simulations are very similar even for complex
scenarios which include thermal feedback on low mass halos. The comparison
between the schemes in terms of the statistical quantities such as the power
spectrum of the brightness temperature fluctuation agree with each other within
10% error throughout the entire reionization history. grizzly seems to perform
slightly better than the semi-numerical approaches considered in Majumdar et
al. (2014) which are based on the excursion set principle. We argue that
grizzly can be efficiently used for exploring parameter space, establishing
observations strategies and estimating parameters from 21-cm observations.
