Sommaire:

The abundance of gravitationally bound objects of a given mass (the halo mass function) is an important tool to predict the effect of non-Gaussian initial conditon on the process of structure formation, and thus to constrain the amount of primordial non-Gaussianity in cosmological perturbations. In the excursion set formalism, the mass function is mapped into the first crossing rate of random walks through a barrier, each walk representing the average matter density on the volume corresponding to the mass scale of interest. The steps of the walks are cross-correlated, the correlation matrix being related to the filter function one chooses to average the density field. I will discuss how to set up an expansion scheme to deal with these correlations for a Gaussian field, and how this can easily incorporate non-Gaussianity. Some extensions to other probes of non-Gaussianity in Large Scale Structure (for instance, the scale dependence bias) will be discussed.

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Pour plus d'informations, merci de contacter Frigerio M.