Constraining Scale-Dependent Non-Gaussianity with Future Large-Scale Structure and the CMB

TL;DR

This paper forecasts how future cosmic microwave background and large-scale structure data can constrain models of primordial non-Gaussianity, especially those with scale-dependent features, using principal component analysis and survey data.

Contribution

It introduces a principal component analysis method for arbitrary scale-dependent non-Gaussianity and forecasts combined constraints from future CMB and LSS surveys.

Findings

Forecasts constraints on scale-dependent f_NL(k) models.

Highlights complementarity of CMB and LSS data.

Proposes a figure of merit for non-Gaussianity measurements.

Abstract

We forecast combined future constraints from the cosmic microwave background and large-scale structure on the models of primordial non-Gaussianity. We study the generalized local model of non-Gaussianity, where the parameter f_NL is promoted to a function of scale, and present the principal component analysis applicable to an arbitrary form of f_NL(k). We emphasize the complementarity between the CMB and LSS by using Planck, DES and BigBOSS surveys as examples, forecast constraints on the power-law f_NL(k) model, and introduce the figure of merit for measurements of scale-dependent non-Gaussianity.