Scale-dependent non-Gaussianity as a generalization of the local model

Abstract

We generalize the local model of primordial non-Gaussianity by promoting the parameter f NL to a general scale-dependent function f NL ( k ). We calculate the resulting bispectrum and the effect on the bias of dark matter halos, and thus the extent to which f NL ( k ) can be measured from the large-scale structure observations. By calculating the principal components of f NL ( k ), we identify scales where this form of non-Gaussianity is best constrained and estimate the overlap with previously studied local and equilateral non-Gaussian models.