In our original calculation, we used a standard approximation known as the "linear bias" [e.g. Mo & White (1996)]. In a follow-up paper (Iliev et al. 2003), we improve upon that treatment by considering the effect of nonlinear clustering. To accomplish this, we develop a new analytical method for calculating the nonlinear Eulerian bias of halos, which should be useful for other applications as well. Predictions of this method are compared with the results of LambdaCDM N-body simulations, showing significantly better agreement than the standard linear bias approximation. When applied to the 21-cm background from minihalos, our formalism predicts fluctuations that differ from our original predictions by up to 30% at low frequencies and small scales. However, within the range of frequencies and angular scales at which the signal could be observable by LOFAR and SKA as currently planned, the differences are small and our original predictions prove robust. Our results indicate that while a smaller frequency bandwidth of observation leads to a higher signal that is more sensitive to nonlinear effects, this effect is counteracted by the lowered sensitivity of the radio arrays. We calculate the best frequency bandwidth for these observations to be Delta nu~2 MHz.
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