Nicholas Kaiser

Abstract Nick Kaiser was a statistical cosmologist of rare creativity, who wrote many deeply influential papers concerning the study of large-scale inhomogeneities in the Universe. His most important achievements were: explaining the biased amplitude of galaxy clustering via the enhanced correlations of rare massive haloes of dark matter; diagnosing how the peculiar velocities associated with structure formation would generate anisotropic redshift-space distortions in galaxy clustering; and analysing the effect of weak gravitational lensing, in which small coherent distortions of the shape of galaxy images could be used to map the dark matter distribution and measure its statistical properties. These theoretical ideas are at the heart of new generations of large galaxy surveys, which aim to use Nick’s methods to probe fundamental aspects of the cosmological model, particularly measuring whether the vacuum density evolves with time, and testing whether Einstein’s relativistic theory of gravity is correct on cosmological scales.