Imprints of primordial non-Gaussianities on large-scale structure: Scale-dependent bias and abundance of virialized objects

Abstract

We study the effect of primordial non-Gaussianity on large-scale structure, focusing upon the most massive virialized objects. Using analytic arguments and $N$-body simulations, we calculate the mass function and clustering of dark matter halos across a range of redshifts and levels of non-Gaussianity. We propose a simple fitting function for the mass function valid across the entire range of our simulations. We find pronounced effects of non-Gaussianity on the clustering of dark matter halos, leading to strongly scale-dependent bias. This suggests that the large-scale clustering of rare objects may provide a sensitive probe of primordial non-Gaussianity. We very roughly estimate that upcoming surveys can constrain non-Gaussianity at the level of $|f_{\mathrm{NL}}|\lesssim 10$, which is competitive with forecasted constraints from the microwave background.