The observed galaxy bispectrum from single-field inflation in the squeezed limit
Abstract
Using the consistency relation in Fourier space, we derive the observed galaxy bispectrum from single-field inflation in the squeezed limit, in which one of the three modes has a wavelength much longer than the other two. This provides a non-trivial check of the full computation of the bispectrum based on second-order cosmological perturbation theory in this limit. We show that gauge modes need to be carefully removed in the second-order cosmological perturbations in order to calculate the observed galaxy bispectrum in the squeezed limit. We then give an estimate of the effective non-Gaussianity due to general relativistic lightcone effects that could mimic a primordial non-Gaussian signal.
Keywords
Cite
@article{arxiv.1805.09189,
title = {The observed galaxy bispectrum from single-field inflation in the squeezed limit},
author = {Kazuya Koyama and Obinna Umeh and Roy Maartens and Daniele Bertacca},
journal= {arXiv preprint arXiv:1805.09189},
year = {2018}
}
Comments
16 pages, 2 figures, accepted for publication in JCAP