Generalized local ansatz for scale-dependent primordial non-Gaussianities and future galaxy surveys

We revisit a possible scale-dependence of local-type primordial non-Gaussianities induced by super-horizon evolution of scalar field perturbations. We develop the formulation based on delta N formalism and derive the generalized form of the local-type bispectrum and also trispectrum which allows us to implement the scale-dependence and suitably compare model prediction with observational data. We propose simple but phenomenologically meaningful expressions, which encompass the information of a wide range of physically motivated models. We also formulate a large-scale power spectrum and bispectrum of biased objects in the presence of the scale-dependent primordial non-Gaussianities. We perform the Fisher analysis for future galaxy surveys and give the projected constraints on the parameters of the generalized local-form of primordial non-Gaussianities.

Automated summary

We investigate the scale-dependence of local-type primordial non-Gaussianities induced by the super-horizon evolution of scalar field perturbations. We develop a formulation based on the delta N formalism and derive the generalized form of the local-type bispectrum and trispectrum, allowing us to compare model predictions with observational data. We propose simple but meaningful expressions that encompass the information of various physically motivated models. We also calculate the large-scale power spectrum and bispectrum of biased objects in the presence of scale-dependent primordial non-Gaussianities. Fisher analysis for future galaxy surveys is performed, providing projected constraints on the parameters of the generalized local-form of primordial non-Gaussianities.