Two-dimensional Topology of Cosmological Reionization
  We study the two-dimensional topology of the 21-cm differential brightness
temperature for two hydrodynamic radiative transfer simulations and two
semi-numerical models. In each model, we calculate the two dimensional genus
curve for the early, middle and late epochs of reionization. It is found that
the genus curve depends strongly on the ionized fraction of hydrogen in each
model. The genus curves are significantly different for different reionization
scenarios even when the ionized faction is the same. We find that the
two-dimensional topology analysis method is a useful tool to constrain the
reionization models. Our method can be applied to the future observations such
as those of the Square Kilometer Array.
