Non-Gaussianity from Large-Scale Structure Surveys

TL;DR

This paper reviews how upcoming large-scale galaxy and cluster surveys can constrain primordial non-Gaussianity using three complementary methods: higher-order correlations, rare object abundance, and halo clustering.

Contribution

It compares three different approaches for constraining primordial non-Gaussianity from large-scale structure data, highlighting their advantages and complementarity.

Findings

Different methods provide complementary constraints.

Large surveys can significantly improve non-Gaussianity limits.

Each approach has unique advantages in analysis.

Abstract

With the advent of galaxy surveys which provide large samples of galaxies or galaxy clusters over a volume comparable to the horizon size (SDSS-III, HETDEX, Euclid, JDEM, LSST, Pan-STARRS, CIP etc.) or mass-selected large cluster samples over a large fraction of the extra-galactic sky (Planck, SPT, ACT, CMBPol, B-Pol), it is timely to investigate what constraints these surveys can impose on primordial non-Gaussianity. I illustrate here three different approaches: higher-order correlations of the three dimensional galaxy distribution, abundance of rare objects (extrema of the density distribution), and the large-scale clustering of halos (peaks of the density distribution). Each of these avenues has its own advantages, but, more importantly, these approaches are highly complementary under many respects.