Rapid calculation of theoretical cosmic microwave background angular power spectra

We have developed a fast method for predicting the angular power spectrum C-l of the cosmic microwave background given cosmological parameters and a primordial power spectrum of perturbations. After precomputing the radiation temperature and gravitational potential transfer functions over a small subspace of the total model parameter space, the rest of the model space (six or more cosmological parameters and arbitrarily many primordial power spectrum parameters) is reached via rapid analytic and semianalytic approximations that are highly accurate on all angular scales for which linear perturbation theory applies. A single power spectrum can be calculated in similar to1 s on a desktop computer. We discuss applications to cosmological parameter estimation.