Figures 10-12

Figure 10

CDM evolution in the Compton drag epoch. If baryons contribute a significant fraction of the total matter density, CDM growth will be slowed between equality and the drag epoch. Held by Compton drag, the baryons do not contribute their self-gravity. For the numerical results, we choose a model that never recombined so that $a_d \gg a_{eq}$.

Figure 11

Velocity overshoot effect. Below the horizon at the drag epoch $k\eta_d \gg 1$, the acoustic velocity at $z_d$ dominates the growing mode and hence the final transfer function. Near the horizon, the acoustic density becomes comparable and shifts the zero points of the oscillation.

Figure 12

Adiabatic CDM transfer function in a high $\Omega_b/\Omega_0=2/3$ case. The analytic solution is essentially exact in the small scale limit. Simple fits based on the BBKS form can cause large errors at the small scale: PD (Peacock \& Dodds 1994) and S (Sugiyama 1995). The fitting function developed here [see equation \Edis\EeqnScaling] works at the $1\%$ level even for this extreme case.