Cosmic complementarity: H-0 and Omega(m), from combining cosmic microwave background experiments and redshift surveys

We show that the detection of acoustic oscillations in both upcoming cosmic microwave background (CMB) satellite experiments and large-redshift survey s can yield 5% determinations of H-0 and Omega(m), an order-of-magnitude im provement over CMB data alone. CMB anisotropies provide the sound horizon a t recombination as a standard ruler. For reasonable baryon fractions, this scale is imprinted on the galaxy power spectrum as a series of spectral fea tures. Measuring these features in redshift space determines the Hubble con stant, which in turn yields Omega(m) once combined with CMB data. Since the oscillations in both power spectra are frozen-in at recombination, this te st is insensitive to low-redshift cosmology.