Primordial nongaussianity and large-scale structure

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Standard inflationary theory predicts that primordial fluctuations in the
universe were nearly Gaussian random. Therefore, searches for, and limits on, primordial nongaussianity are some of the most fundamental tests of inflation and the early universe in general. I first briefly review the history of its measurements from the cosmic microwave background anisotropies and large-scale structure in the universe. I then present results from recent work where effects of primordial nongaussianity on the distribution of largest virialized objects was studied numerically and analytically. We found that the bias of dark matter halos takes strong scale dependence in nongaussian cosmological models. Therefore, measurements of scale dependence of the bias, using various
tracers of large-scale structure, can - and do - constrain primordial
nongaussianity more than an order of magnitude better than previously thought.