| After the Cosmic Microwave Background, structure above a characteristic scale length (∼10 Mpc/h) is the best probe of the power spectrum in the linear regime. Galaxy clusters' peculiar motions are responses to gradients in these large modes and, like gravitational lensing, are sensitive to all the matter present, dark and luminous. Recent technological advances in radio and submillimeter astronomy allow for the measurement of the Sunyaev-Zel'dovich effect in the largest virialized clusters, which includes a separable component due to any radial (peculiar) motion. With the prospect of galaxy cluster catalogs to deep redshift, we developed the tools to estimate how different cosmologies affect the statistics of these peculiar motions and, vice versa, how well such catalogs can constrain the actual values of cosmological parameters. In addition, we studied how peculiar velocities can be used to reconstruct the large modes of the gravitational potential. Finally, large scale N-body simulations of structure will be used to test the applicability of linear theory, and to more accurately predict the statistical distribution of what astronomers will actually measure. |
