Radio map of redshifted 21cm emission against the CMB in an open CDM
cosmology at z = 8.5 (the results would be similar for a &Lambda CDM
cosmology). The linear size of the simulation volume is
20h-1 (comoving) Mpc. The point spread function of the
synthesized beam is assumed to be a spherical top-hat with a width of
2 arcmin. The frequency window is 1 MHz around a central frequency of
150 MHz. The color intensity runs from 1 to 6 &mu Jy per beam. For
clarity, the contour levels outline regions with signal greater than
4&mu Jy per beam. (From Tozzi et al. 2000.)