With new detectors and dedicated efforts, the SZ effect should soon become a useful tool for probing cluster evolution and structure formation. In particular, the y distribution function may be useful for constraining the power spectrum of density perturbations, both by observing the distribution at the current epoch and by determining the sense of its evolution with redshift. Observations of the CMB anisotropy at arcminute scales also appear to be a powerful way to constrain models of structure formation. We found that, for example, unbiased CDM-like scenarios result in rather large anisotropies, perhaps in violation of existing limits. This later statement must be explored further by adequately modeling the nongaussian nature of the cluster induced perturbations.
Although we only considered the case of a lfat universe here, one must not overlook the value of the SZ effect for studying an open universe. Because of its unique distance independence, one can observe distant clusters with the same ease as those nearby. This is a significant advantage over the X-ray observations, which suffer from a lack of photons from distant clusters. Thus the SZ effect can be used to search for the high redshift clusters expected in an open universe.