Imprints of Oscillatory Bispectra on Galaxy Clustering

TL;DR

This paper investigates how oscillatory bispectra from inflation models influence galaxy clustering, revealing scale-dependent halo bias modulations that are challenging to detect with upcoming surveys.

Contribution

It provides a detailed analysis of halo bias oscillations caused by resonant non-Gaussianity using Conformal Fermi Coordinates, highlighting their unique scale and mass dependence.

Findings

Bias oscillates with scale similar to equilateral non-Gaussianity

Bias shows peculiar modulation with halo mass

Upcoming surveys are unlikely to detect the small amplitude signal

Abstract

Long-short mode coupling during inflation, encoded in the squeezed bispectrum of curvature perturbations, induces a dependence of the local, small-scale power spectrum on long-wavelength perturbations, leading to a scale-dependent halo bias. While this scale dependence is absent in the large-scale limit for single-field inflation models that satisfy the consistency relation, certain models such as resonant non-Gaussianity show a peculiar behavior on intermediate scales. We reconsider the predictions for the halo bias in this model by working in Conformal Fermi Coordinates, which isolate the physical effects of long-wavelength perturbations on short-scale physics. We find that the bias oscillates with scale with an envelope similar to that of equilateral non-Gaussianity. Moreover, the bias shows a peculiar modulation with the halo mass. Unfortunately, we find that upcoming surveys will be unable to detect the signal because of its very small amplitude. We also discuss non-Gaussianity due to interactions between the inflaton and massive fields: our results for the bias agree with those in the literature.