We study cosmic reionization by the mean of numerical simulations and predict the resulting 21 cm signal. We have developed a new code, LICORICE, for 3D radiative transfer which deals with both Ly-alpha line transfer and the ionizing continuum. This is the first work including Lyman-alpha photons which are necessary to correctly predict the absorption phase of the 21 cm signal (Ly-alpha pumping i. e. Wouthuysen-Field effect). We combined N-body (DM+gas) simulations and 3D radiative transfer to estimate the ionization state of the IGM. The simulations are run with 2563 DM particles and 2563 baryon particles in two different box-sizes: 20h-1 Mpc3 and 100h-1 Mpc3. In our simulation, full reionization occurs around the redshift 6 which is in good agreement with the quasar absoption observation of SDSS. Thompson optical depth are consistent within 1-sigma value from third-year WMAP result. We find that including\r\nan accurate evaluation of the Ly-alpha pum
ping significantly modifies the 21-cm emission maps, especially in the case of the 100h-1 Mpc3 box.
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